Startseite Development and performance improvement of a novel zero cross-correlation code for SAC-OCDMA systems
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Development and performance improvement of a novel zero cross-correlation code for SAC-OCDMA systems

  • Xiang Li , Qing-an Ding EMAIL logo , Bowen Nie , Changqing Liu , Xiaojuan Wang , Juan Song , Chaofan Li und Lijun Zhang
Veröffentlicht/Copyright: 8. September 2020
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Journal of Optical Communications
Aus der Zeitschrift Journal of Optical Communications Band 44 Heft s1

Abstract

In order to improve the performance of the Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) system, a zero cross-correlation (ZCC) code named double weight multi-diagonal (DW-MD) is proposed with constant weight (CW) or variable weight (VW). Mathematical results illustrate that it is feasible to reduce the number of filters without sacrificing system performance by using the CW DW-MD code instead of the multi-diagonal (MD) code. And for the VW DW-MD code, the supportable number of users for lower code weight W L (3) at bit error rate (BER) of 10−3 (voice) is 43, medium code weight W M (4) at BER of 10−9 (data) is 29, and higher code weight W H (5) at BER of 10−12 (video) is 32. Finally, the analysis about the position of chips “1” is given, and the simulation setups show that the CW DW-MD code outperforms the MD code when Gaussian optical filter is used.

Keywords: double weight multi-diagonal (DW-MD) code; spectral amplitude coding-optical code division multiple access (SAC-OCDMA); variable weight code; zero cross-correlation (ZCC) code

1 Introduction

Optical Code Division Multiple Access (OCDMA) is an attractive technology in the optical network due to the properties of asynchronous access to the entire channel and great capacity in bursty traffic [1]. In particular, Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) techniques stand out because of the ability to eliminate multiple-access interference (MAI) [2], [3], [4]. And with light-emitting diodes (LEDs) as the light source, the SAC-OCDMA network is inexpensive and simple [5], [6]. The performance of the SAC-OCDMA system depends to a large extent on the choice of coding scheme, and many Spectral-Amplitude-Coding (SAC) codes have been reported, such as modified quadratic congruence (MQC) codes [3], double weight (DW) code family [7], [8], Khazani-Syed (KS) code [9], Random Diagonal (RD) code [10], Multi-Service (MS) code [11], Enhanced multi-diagonal (EMD) code [12], Zhang finite-difference (ZFD) code [13] and a code based on construction of parity check matrix of Low density parity check (LDPC) codes [14].

In addition to these codes designed with constant code weight (CW), the variable weight (VW) codes are also reported. And with the property of higher code weight representing better performance, they can be utilized to support multimedia service (e.g., voice, video, and data transmission) and provide different quality of service (QoS) for the various requirements in SAC-OCDMA network [15]. Some of them are VW KS code [9], VW RD code [10], VW MS code [16] and a VW code based on enhanced and modified DW codes [17].

All of the above CW and VW codes cannot avoid the impact of phase-induced intensity noise (PIIN). Thus, some zero cross-correlation (ZCC) codes along with the spectral direct detection (SDD) [18] technique has been reported to eliminate the PIIN for the SAC-OCDMA system. Such as ZCC code [19], Multi-Diagonal (MD) code based on the orthogonal matrix [20], new ZCC code with satisfactory code lengths [21], VW ZCC Code [22] and Zero Cross Correlation Code (ZCCC) with CW and VW [23].

There are also some two dimensional spectral/spatial codes have been proposed in order to improve the system capacity. Such as Two Dimensional-Single Weight Zero Cross Correlation (2D-SWZCC) code [24], two-dimensional hybrid ZCC/MD code [25], two-dimensional Fixed Right Shift (FRS) code [26] and two-dimensional Enhanced multi-diagonal (2D-EMD) Code [27]. Most of the two dimensional spectral/spatial codes are usually constructed on the basis of one-dimensional codes. Therefore, it is still very important to design one-dimensional SAC-OCDMA codes with excellent performance.

The code family for SAC-OCDMA system continues to grow, and the choice of an appropriate code with CW or VW is still an open issue. However, the position of chips “1” in the code sequences, one of the important factors affecting system performance, is not analyzed in the previous works. In this paper, a new ZCC code named double weight multi-diagonal (DW-MD) code is constructed based on the DW codes and MD code. In order to reduce the number of filters used in the system and make the SAC systems more cost-effective, the DW-MD code is designed with putting two chips “1” together compared to the MD code. And using the mapping technique, the DW-MD code with VW is given for supporting multimedia service. Furthermore, the effect of chips “1” position on system performance is qualitatively analyzed and evaluated by simulation in this paper.

This paper is organized as follows. In Section 2, construction of the DW-MD code with CW and VW are presented. In Section 3, mathematical and analysis results for evaluating the performance of the DW-MD code are given. Analysis of chips “1” position and simulation setup is given in section 4. Finally, conclusions are drawn in Section 5.

2 Construction of DW-MD code

2.1 Introduction of MD and DW codes

Construction of the DW-MD code is based on the DW codes and MD code.

As reported in [20], the MD code is constructed by using V alternating M-dimensional unit diagonal matrices and anti-tangle matrices (V is code weight and M is the number of users):

(1) [ [ 1 0 ⋯ 0 0 1 ⋯ 0 ⋮ ⋮ ⋱ ⋮ 0 0 ⋯ 1 ] M × M , [ 0 ⋯ 0 1 0 ⋯ 1 0 ⋮ ⋯ ⋱ ⋮ 1 ⋯ 0 0 ] M × M , ⋯ , [ 1 0 ⋯ 0 0 1 ⋯ 0 ⋮ ⋮ ⋱ ⋮ 0 0 ⋯ 1 ] M × M ⏟ number of the matries is  V   ]

The DW codes are designed with the property that chip “1” occurs in pairs [7], [8]. Therefore, when the DW codes are used in SAC-OCDMA systems, the number of filters can be reduced by almost half. The principle of reducing the number of filters is shown in Figure 1. Here, the one filter with a bandwidth of 2∆f (central wavelength of f c  = (f 1 + f 2)/2) can be used to replace the two filters with a bandwidth of ∆ f(central wavelength of f 1 and f 2, respectively).

Figure 1: Schematic diagram for reducing the number of filters.
Figure 1:

Schematic diagram for reducing the number of filters.

2.2 Construction of DW-MD code with constant weight

Construction steps of the DW-MD with CW code are as follows.

Step 1:

Defining the code weight W and the number of users N, where W and N are positive integer numbers. And the code length L is given as L = N × W.

Step 2:

Constructing a sequence of matrices S w (w = 1, 2, 3 …, w max) with only elements “1” and “0” according to W and N, and the S w (i, j) (i = 1, 2, 3 … , N) represents the element of the ith row and the jth column of each matrix respectively.

  1. When W is an odd number, the value of w max is (W + 1)/2. S 1 is a matrix with N × N dimensions, and S w (w = 2, 3, … , w max) are matrices of power N × 2 N, the position of elements “1” in Sw is determined by

(2) { S w   =   1 ( i , j ) = 1 , for   j = i S w   =   odd number, w ≠ 1 ( i , j ) = 1 , for   j = 2 i − 1 , 2 i S w   =   even number ( i , j ) = 1 , for   j = 2 ( N + 1 − i ) − 1 , 2 ( N + 1 − i )

where, i is varied from one to N, and

(3) S 1 = [ 1 0 ⋯ 0 0 1 ⋯ 0 ⋮ ⋮ ⋱ ⋮ 0 0 ⋯ 1 ] N × N , S 2 = [ 0 0 ⋯ ⋯ 0 0 1 1 0 0 ⋯ ⋯ 1 1 0 0 ⋮ ⋮ ⋱ ⋱ ⋮ ⋮ ⋮ ⋮ 1 1 ⋯ ⋯ 0 0 0 0 ] N × 2   N , S 3 = [ 1 1 0 0 ⋯ ⋯ 0 0 0 0 1 1 ⋯ ⋯ 0 0 ⋮ ⋮ ⋮ ⋮ ⋱ ⋱ ⋮ ⋮ 0 0 0 0 ⋯ ⋯ 1 1 ] N × 2   N , ⋯ , S ( W + 1 ) / 2

  1. When W is the even number, the value of w max is W/2. S w (w = 1, 2, 3 … , w max) are matrices of N × 2 N, the position of elements “1” in S w is determined by

(4) { S w   =   odd number ( i , j ) = 1 ,   for   j = 2 i − 1 , 2 i S w   =   even number ( i , j ) = 1 ,   for   j = 2 ( N + 1 − i ) − 1 , 2 ( N + 1 − i )

where, i is varied from one to N, thus

(5) S 1 = [ 1 1 0 0 ⋯ ⋯ 0 0 0 0 1 1 ⋯ ⋯ 0 0 ⋮ ⋮ ⋮ ⋮ ⋱ ⋱ ⋮ ⋮ 0 0 0 0 ⋯ ⋯ 1 1 ] N × 2   N , S 2 = [ 0 0 ⋯ ⋯ 0 0 1 1 0 0 ⋯ ⋯ 1 1 0 0 ⋮ ⋮ ⋱ ⋱ ⋮ ⋮ ⋮ ⋮ 1 1 ⋯ ⋯ 0 0 0 0 ] N × 2   N , S 3 = [ 1 1 0 0 ⋯ ⋯ 0 0 0 0 1 1 ⋯ ⋯ 0 0 ⋮ ⋮ ⋮ ⋮ ⋱ ⋱ ⋮ ⋮ 0 0 0 0 ⋯ ⋯ 1 1 ] N × 2   N , ⋯ , S W / 2

Step 3:

The total combination of the S w (w = 1, 2, 3 … , w max) in matrices (3) or (5) represents the DW-MD code as a matrix of power N × L.

(6) DW - MD ( W ) = [ S 1 ⋮ S 2 ⋮ ⋯ ⋮ S w max ] N × L

For example, to construct a DW-MD code with W = 3 and N = 3 according to the previous steps.

Therefore, L = N × W = 9, W is an odd number and w max = 2. For i = 1, 2, 3, the matrices S w (w = 1, 2) can be expressed as:

(7) S 1 = [ 1 0 0 0 1 0 0 0 1 ] 3 × 3 , S 2 = [ 0 0 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 0 ] 3 × 6

and the DW-MD code will be:

(8) DW - MD ( 3 ) = [ S 1 ⋮ S 2 ] 3 × 9 = [ 1 0 0 ⋮ 0 0 0 0 1 1 0 1 0 ⋮ 0 0 1 1 0 0 0 0 1 ⋮ 1 1 0 0 0 0 ] 3 × 9

The DW-MD code concentrates on the advantages of MD and DW codes. On the one hand, MAI can be fully eliminated and the PIIN can be suppressed due to the property of ZCC (same as MD code). On the other hand, the number of filters and the complexity of the system can be reduced because the two chips “1” are adjacent (same as DW code). Besides, the DW-MD code can be generated easily and efficiently with any code weight and the number of users.

2.3 Construction of DW-MD code with variable weight

Construction of DW-MD code with VW for supporting multimedia service with different QoS in SAC-OCDMA network is described here. It consists of several CW DW-MD code matrices by using the mapping technique and each code weight can be chosen independently to satisfy the required service quality. The VW code with J number of service classes is described as where, N j is the number of users of the jth CW code matrix whose code weight is W j , and W 1 > W 2 > ⋯ > W J .

Thus, the total number of users N v is expressed as

(10) N v = ∑ j = 1 J N j

and the code length L v is given as

(11) L v = ∑ j = 1 J N j ⋅ W j

As shown in Figure 2, the VW DW-MD code for supporting QoS differentiation is designed. The weights of 5, 3, and 2 are chosen for representing higher, medium and lower class, respectively. There is a total of 10 subscribers (four users with higher class, three users with medium class and three users with lower class), and the total length of VW DW-MD code is 41 from the Eq. (10).

Figure 2: Generated VW DW-MD code for 10 numbers of subscribers with different weights of 5, 4, and 3.
Figure 2:

Generated VW DW-MD code for 10 numbers of subscribers with different weights of 5, 4, and 3.

3 Theoretical analysis and results

3.1 System setup

The schematic diagram of the SAC-OCDMA system with the CW DW-MD code is shown in Figure 3. The system consists of the transmitter and receiver. At the transmitter, the optical bandpass filters are used to encode the optical spectra of the three users according to the DW-MD code sequence. After being modulated with the given data by the Mach–Zehnder Modulators (MZMs), three branches of encoded optical spectra are multiplexed by the Combiner and then sent to the receiver through the Single Mode Fiber (SMF). Finally, direct detection technique is used. The divided optical signals are decoded by using the filters with unique central wavelengths respectively and retrieved by means of photo-diode and Low Pass Filter (LPF). It is noted that not all the “1” s must be detected in the SDD technique for the CW system, and the number of detected “1” s can be determined according to the actual situation.

Figure 3: Schematic diagram of SAC-OCDMA system for CW DW-MD code.
Figure 3:

Schematic diagram of SAC-OCDMA system for CW DW-MD code.

As shown in Figure 4, the system setup for VW DW-MD code is similar to the CW code and the filters at the encoder and decoder are determined by the VW code sequence. However, all the “1” s should be used in the SDD technique so as to ensure that the code weight of each class remains unequal. Here, the lower code weight (i.e., W = 1) is associated with low service demand represented as class 1, and the higher code weight is assigned to class 3 owning high QoS.

Figure 4: Schematic diagram of SAC-OCDMA system for VW DW-MD code.
Figure 4:

Schematic diagram of SAC-OCDMA system for VW DW-MD code.

3.2 Derivation of BER formula

In the following analysis, Gaussian approximation is used to evaluate the performance of the CW and VW DW-MD code. And the SAC-OCDMA system performance is characterized by referring to BER. Because the DW-MD codes have the ZCC property and there are no spectra overlapping among different users, only the effects of both shot and thermal noise are considered and the PIIN is ignored. Consequently, the total variance of noise for the system can be written as

(12) σ 2 = < i shot 2 > + < i thermal 2 > = 2 e I B + 4 K b T n B R L

where, e is the electron’s charge, I is the average photocurrent at the receiving photo-diode, B is noise-equivalent electrical bandwidth of the receiver, K b is Boltzmann’s constant, T n is receiver noise temperature and R L is receiver load resistor.

In order to evaluate the SAC-OCDMA system performance accurately, it is assumed that:

  1. The light source of each user is ideally unpolarized and its spectrum is flat over the bandwidth [v 0 − ∆v/2, v 0 + ∆v/2] where v 0 is the central optical frequency and ∆v is the optical source bandwidth expressed in Hertz.

  2. The spectral width of each power spectral component is identical.

  3. The power of each user at the transmitter is equal.

  4. The bit stream of each user is synchronized.

Moreover, power spectral density (PSD) of received optical signals at the photo-diode can be written as

(13) G ( v ) = P s r Δ v ∑ n = 1 N d n ∑ i = 1 L C n ( i ) ⋅ rec ( i )

where, P sr represents the effective power at the receiver, N is the active users, L is the DW-MD code length, d n is the data bit of the nth user that is ‘‘1’’ or ‘‘0’’, rec(i) in Eq. (13) is explained as

(14) rec ( i ) = u [ v − v 0 − Δ v 2 L ( − L + 2 i − 2 ) ] − u [ v − v 0 − Δ v 2 L ( − L + 2 i ) ] = u [ Δ v L v ]

and u(v) is the unit step function expressed as

(15) u ( v ) = { 1 ,   v ≥ 0 0 ,   v ≤ 0

Let C n (i) be the ith element of nth CW DW-MD code sequence and according to the correlation properties, the SDD technique for the DW-MD code can be represented as

(16) ∑ i = 1 L C n ( i ) ⋅ C l ( i ) = { W ,   n = l 0 ,   n ≠ l

From the Eqs. (13) and (16), the PSD at the photo-detector of the lth receiver during one period can be written as:

(17) G ( v ) = P s r Δ v ∑ n = 1 N d n ∑ i = 1 L C n ( i ) C l ( i ) ⋅ u ( Δ v L )

and then

(18) ∫ 0 ∞ G ( v ) d v = ∫ 0 ∞ P s r Δ v ∑ n = 1 N d n ∑ i = 1 L C n ( i ) C l ( i ) ⋅ u ( Δ v L ) d v = P s r Δ v ⋅ Δ v L ⋅ ∑ n = 1 N d n ∑ i = 1 L C n ( i ) C l ( i ) = P s r W L

The photocurrent I can be found as

(19) I = ℜ ∫ 0 ∞ G ( v ) d v = ℜ P s r W L

where, ℜ is the responsivity of the photo-detectors given by ℜ = μe/(hvc), μ is the quantum efficiency, h is Planck’s constant, and v c is the central frequency of the original broad-band optical pulse.

Substituting Eq. (19) in Eq. (12), it can be obtained that

(20) σ 2 = 2 e B ℜ P s r W L + 4 K b T n B R L

Noting that the probability of sending bit “1” at any time for each user is 1/2, Eq. (17) becomes

(21) σ 2 = e B ℜ P s r W L + 4 K b T n B R L

Thus, for users with code weight W, the average Signal to Noise Ratio (SNR) can be calculated as

(22) S N R = ( ℜ P s r W / L ) 2 e B ℜ P s r W / L + 4 K b T n B / R L

Using Gaussian approximation, the BER can be expressed as

(23) P e = 1 2 e r f c S N R 8

And for VW DW-MD code, the Eq. (16) can be expressed as

(24) ∑ i = 1 L v C n ( i ) ⋅ C l ( i ) = { W j ,   n = l 0 ,   n ≠ l

By the similar derivation to CW DW-MD code, the average SNR j for VW DW-MD code with code weight W j can be calculated as

(25) S N R j = ( ℜ P s r W j / L v ) 2 e B ℜ P s r W j / L v + 4 K b T n B / R L

Using Gaussian approximation, the BER j can be also expressed:

(26) P e j = 1 2 e r f c S N R j 8

3.3 Mathematical results and discussion

The parameters used in the numerical analysis are listed in Table 1. Comparison of the number of filters used at the encoder/decoder between the CW DW-MD and MD codes is given in Figure 5. For the same number of users and code weight, fewer filters are used with the DW-MD code due to the property that chip ‘1’ occurs in pairs, and half number of filters can be reduced when the code weight is an even number (e.g., W = 4). It is noted that the same number of filters (two filters per encoder) are required for the DW-MD code with W = 4 and W = 3, but both filters are double bandwidth for W = 4 while only one for W = 3.

Table 1:

System parameters description and specifications.

Symbol Parameter Value
E Electron charge 1.6 × 10−19 C
B Electrical bandwidth 311 MHz
K b Boltzmann’s constant 1.38 × 10−23 J/K
Tn Received noise temperature 300 K
R L Received load resistor 1030 Ω
Μ Photodetector quantum efficiency 0.6
∆v Linewidth of broadband source 3.7 THz
λ0 Operating wavelength 1550 nm
P sr Received optical power −10 dBm
H Planck’s constant 6.626 × 10−34 J s
Figure 5: Comparison of number of filters used at the encoder/decoder between MD and DW-MD codes.
Figure 5:

Comparison of number of filters used at the encoder/decoder between MD and DW-MD codes.

As shown in Figure 6, the performance of DW-MD code (W = 4), MD code (W = 4) [20], KS code (W = 6) [10] and MS code (W = 4 and N B  = 3) [12] are investigated as log of BER against the total number of active users operating at P sr of −10 dBm. Due to the same ZCC and no PIIN, the DW-MD code and MD code have almost the same BER performance and are superior to other codes. This further indicates that it is feasible to reduce the number of filters without sacrificing system performance by using the DW-MD code instead of the MD code.

Figure 6: Comparison of the BER performance between DW-MD code and other codes.
Figure 6:

Comparison of the BER performance between DW-MD code and other codes.

Figure 7 illustrates the variations of the BER against the number of users (each weight of VW DW-MD code). For supporting multimedia service, the lower code weight W L , medium code weight W M , and higher code weight W H are set as 3, 4 and 5, respectively. The Supportable number of users for W L at BER of 10−3 (voice) is 43, W M at BER of 10−9 (data) is 29, and W H at BER of 10−12 (video) is 32.

Figure 7: Variation of BER against number of each weight users with W L  = 3, W M  = 4 and W H  = 5.
Figure 7:

Variation of BER against number of each weight users with W L  = 3, W M  = 4 and W H  = 5.

Figure 8 depicts BER versus the number of users (each weight) for VW code by varying the W L or W H and keeping another code weight fixed. The combinations of two code weights (W L , W H ) are taken as (3, 4), (3, 5) and (4, 5). On one hand, increasing the W H from four to five and keeping the W L fixed at three leads to the worse BER for W L users and better performance for W H users. On the other hand, the BER for W L users and W H users decreased and increased respectively when the W H is fixed at five and W L increases from three to four Eq. (11) indicates whether it is to increase W L or W H , the total code length L v should be increased. And it is obvious that the BER performance becomes worse for the fixed code weight (W L or W H ) as the increase of L v according to the Eq. (26).

Figure 8: Performance of the VW DW-MD code on varying the value of W L or W H .
Figure 8:

Performance of the VW DW-MD code on varying the value of W L or W H .

In Figure 9, BER is plotted against the number of simultaneous users with the number of lower code weight users (N L ) being 10, 20, and 30, respectively. As the N L increases, both the W L and W H users have a better BER performance. Thus, the higher the proportion of users with W L , the better the system performance. This is because increasing the N L can decrease the total code length L v and provide a lower BER for the whole system according to the Eqs. (11) and (26).

Figure 9: BER against the number of active users with N L  = 10, 20, and 30.
Figure 9:

BER against the number of active users with N L  = 10, 20, and 30.

4 Simulations

4.1 Analysis of interference between two adjacent “1”s

The above mathematical analysis and discussion are based on the assumption that there is no interference between two adjacent chips “1”. However, filters used at the encoder/decoder in SAC-OCDMA systems are not ideal filters in real scenario, and there is indeed interference between the two adjacent wavelength channels. Take the Gaussian Optical Filter commonly used in SAC-OCDMA systems as an example, and its theoretical model is shown in Figure 10 (theoretical model of ideal filter can be obtained from Figure 1). According to Figure 10 where the interference is represented as ∆S, it can be concluded that the construction with two discrete “1” (MD code) has more interference than two adjacent “1”s (DW-MD) (4∆S for the former and 2∆S for the latter when the code weight is 2). If there is only one chip “1” needed at the decoder in the SDD technique, the filter with a bandwidth of ∆f and the central wavelength of f c can be the optimal choice.

Figure 10: Theoretical model of Gaussian Optical Filters used at encoder/decoder.
Figure 10:

Theoretical model of Gaussian Optical Filters used at encoder/decoder.

4.2 Simulation setup

The simulation setup for the CW DW-MD code is shown in Figure 11. There are five users in the SAC-OCDMA system, and the data rate is set as 1.25 Gbps. The a.u. value of Bias Generator (d.c. source.) is set as one. The spectral width is set as 0.8 nm for each chip and the mapping of DW-MD code (W = 4) and wavelength for each user is given in Table 2.

Figure 11: Simulation setup of SAC-OCDMA using CW DW-MD code with code weight of 4.
Figure 11:

Simulation setup of SAC-OCDMA using CW DW-MD code with code weight of 4.

Table 2:

Mapping of DW-MD code (W = 4) and wavelength (1542.8∼1558 nm) for each user.

nm 1542.8 1543.6 1544.4 1545.2 1546 1546.8 1547.6 1548.4 1549.2 1550
User 1 1 1 0 0 0 0 0 0 0 0
User 2 0 0 1 1 0 0 0 0 0 0
User 3 0 0 0 0 1 1 0 0 0 0
User 4 0 0 0 0 0 0 1 1 0 0
User 5 0 0 0 0 0 0 0 0 1 1
nm 1550.8 1551.6 1552.4 1553.2 1554 1554.8 1555.6 1556.4 1557.2 1558
User 1 0 0 0 0 0 0 0 0 1 1
User 2 0 0 0 0 0 0 1 1 0 0
User 3 0 0 0 0 1 1 0 0 0 0
User 4 0 0 1 1 0 0 0 0 0 0
User 5 1 1 0 0 0 0 0 0 0 0

At the transmitter, the LED is utilized as a broadband light source whose parameters are set as the wavelength of 1550 nm and bandwidth of 3.75 THz (30 nm), WDM Demux and Mux are used for encoding the optical spectra, a pseudo-random bit sequence (PRBS) generator and a non-return-zero (NRZ) pulse generator are used to generate the data signal for each user, and the Mach–Zehnder Modulator is utilized as external intensity modulator. According to ITU-T G.652 standard, the 20 km standard single mode optical fiber (SMF) with the dispersion of 16.75 ps/nm/km and attenuation of 0.2 dB/km is chosen to connect the transmitter and receiver.

And at the receiver, the SDD technique is applied to detect signals. The Gaussian Optical Filter with the bandwidth of 0.8 nm is utilized to filter the unique wavelength chips for each user, and the photo-detector with dark current value being 5 nA and 0.75 GHz. Low Pass Bessel Filter is applied for recovering the original electrical signal. It is noted that the channel bandwidth of WDM Demux and Mux are set as 1.6 nm (represent two “1” s with the bandwidth of 0.8 nm) for reducing the number of filters at the encoder. And the wavelength of Gaussian Optical Filter is set as the center of two adjacent wavelengths for mitigating interference from other users.

The simulation setup for MD code is shown in Figure 12, and all the parameters are the same as that shown in Figure 11 except for the encoder and decoder corresponding to the code sequence. The mapping of MD code (W = 4) and wavelength for each user is given in Table 3.

Figure 12: Simulation setup of SAC-OCDMA using MD code with code weight of 4.
Figure 12:

Simulation setup of SAC-OCDMA using MD code with code weight of 4.

Table 3:

Mapping of MD code (W = 4) and wavelength (1542.8∼1558 nm) for each user.

nm 1542.8 1543.6 1544.4 1545.2 1546 1546.8 1547.6 1548.4 1549.2 1550
User 1 1 0 0 0 0 0 0 0 0 1
User 2 0 1 0 0 0 0 0 0 1 0
User 3 0 0 1 0 0 0 0 1 0 0
User 4 0 0 0 1 0 0 1 0 0 0
User 5 0 0 0 0 1 1 0 0 0 0
nm 1550.8 1551.6 1552.4 1553.2 1554 1554.8 1555.6 1556.4 1557.2 1558
User 1 1 0 0 0 0 0 0 0 0 1
User 2 0 1 0 0 0 0 0 0 1 0
User 3 0 0 1 0 0 0 0 1 0 0
User 4 0 0 0 1 0 0 1 0 0 0
User 5 0 0 0 0 1 1 0 0 0 0

4.3 Simulation results and discussion

4.3.1 Simulation with Gaussian Optical Filter

Performance of the system with the DW-MD and the MD codes is characterized in terms of the BER and eye pattern. As shown in Figure 13, eye patterns of one user using (a) DW-MD and (b) MD code clearly depict that the DW-MD code gives a more open eye and a better BER. Furthermore, Table 4 lists the BER values of the five users in the simulation systems using the DW-MD and MD codes, and the BER values of the two codes differ by 8∼14 orders of magnitude. This is because the DW-MD code can reduce the interference by the structure of two adjacent “1” s (analysis of the Figure 10).

Figure 13: Eye diagram for one user of SAC-OCDMA system with (a) DW-MD code and (b) MD code when using Gaussian Optical Filter.
Figure 13:

Eye diagram for one user of SAC-OCDMA system with (a) DW-MD code and (b) MD code when using Gaussian Optical Filter.

Table 4:

BER values of five users with the DW-MD and MD codes when using Gaussian Optical Filters.

BER value of User 1 User 2 User 3 User 4 User 5
DW-MD 2.293 × 10−17 2.559 × 10−17 4.670 × 10−19 6.095 × 10−16 5.068 × 10−18
MD 5.218 × 10−9 4.254 × 10−5 1.414 × 10−5 2.459 × 10−5 4.555 × 10−10

In order to further analyze the performance of DW-MD and MD codes, the fiber length between the transmitter and receiver is changed from 10 to 50 km. And the BER of the two codes versus fiber length is observed at two different data rates (622 Mbps and 1.25 Gbps). Figure 14 shows that BER increases with increasing SMF length, which can be attributed to the increasing attenuation and dispersion of SMF.

Figure 14: BER of DW-MD and MD codes versus Fiber Length at two different data rates.
Figure 14:

BER of DW-MD and MD codes versus Fiber Length at two different data rates.

Moreover, it is observed that the performance advantages of DW-MD code are obvious. In the range of 10–40 km, the SAC-OCDMA system with DW-MD code transmitted at higher rate (1.25 Gbps) performs better than that with MD code transmitted at lower rate (622 Mbps). And for lengths of up to 40 km, the proposed DW-MD has the ability to provide nominal performance for an acceptable BER of 10–9 at 1.25 Gbps of data.

4.3.2 Simulation with rectangle optical filter

In the next simulation, the Rectangle Optical Filters are utilized to replace the Gaussian Optical Filters at the encoder and decoder and other settings and parameters remain unchanged. The BER values of the five users in the SAC-OCDMA systems using the DW-MD and MD codes are given in Table 5, and the BER difference between two corresponding users does not exceed two orders of magnitude. Furthermore, as a sample, the eye diagrams for one user using DW-MD code and MD code are shown in Figure 15 (a) and (b), respectively. Obviously, the two users have a very close eye quality. This is because when using the Rectangle Optical Filters, there is no interference between adjacent filter channels and the effect of chips “1” position on system performance does not exist (theoretical model of ideal Rectangle Optical Filter is shown in Figure 1).

Table 5:

BER values of five users with the DW-MD and MD codes when using Rectangle Optical Filters.

BER value of User 1 User 2 User 3 User 4 User 5
DW-MD 2.293 × 10−17 3.771 × 10−21 5.488 × 10−17 1.186 × 10−18 1.656 × 10−17
MD 4.604 × 10−18 2.033 × 10−19 1.783 × 10−17 2.991 × 10−17 5.163 × 10−19
Figure 15: Eye diagram for one user of SAC-OCDMA system with (a) DW-MD code and (b) MD code when using Rectangle Optical Filters.
Figure 15:

Eye diagram for one user of SAC-OCDMA system with (a) DW-MD code and (b) MD code when using Rectangle Optical Filters.

From the above analysis, it can be easy to conclude that the DW-MD and MD codes have a similar performance when the ideal Rectangle Optical Filters are utilized, which indirectly reveal that the effect of chips “1” position on system performance cannot be ignored when the non-ideal optical filter (e.g., Gaussian Optical Filter) is used at the encoder/decoder in the real scenario.

5 Conclusions

A new ZCC code named DW-MD code has been developed to reduce the number of filters used in the SAC-OCDMA system with the feature of two adjacent chips “1”. And the DW-MD code with variable weight is also constructed to support multimedia in SAC-OCDMA system by associating several different CW code matrices and using the mapping technique. The VW DW-MD code can be chosen independently for each code weight to satisfy the required service quality. Theoretical analysis shows that the DW-MD code can be used instead of the MD code to reduce the number of filters without sacrificing system performance under the ideal conditions. Here, one filter with a larger bandwidth (doubled) can be used instead of using two filters (represent two distinct chips ‘1’). The ability of VW DW-MD code to support multimedia service is also verified, and results indicate that the users with lower code weight W L , medium code weight W M , and higher code weight W H have the higher BER, medium BER and lower BER, respectively. In terms of changing the W L or W H and keeping another code weight fixed, increasing W L or W H results in an increase in the total code length L v , and the performance for the fixed code weight (W H or W L ) deteriorates. In addition, the number of lower code weight users (N L ) with different values (i.e., 10, 20 and 30) are set for the VW code with the combination of (3, 5). It is shown that increasing the N L decreases the total code length and provides better performance for both the W L and W H . Finally, the performance comparison of the MD code and proposed CW code is given through qualitative analysis and simulation setups. The proposed code provides a significant performance improvement compared with the MD code when the Gaussian Optical Filters are used. In summary, the overall results demonstrate that the DW-MD code can be a code candidate that makes the SAC-OCDMA system more cost-effective, and the VW DW-MD code is suitable for supporting multimedia service in optical networks.

Corresponding author: Qing-an Ding, College of Electronic and Information Engineering, Shandong University of Science and Technology, Qingdao, 266590, China, E-mail:

Funding source: Shandong Natural Science Foundation

Award Identifier / Grant number: ZR2017MF070

Funding source: Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents

Award Identifier / Grant number: 2016RCJJ012

Funding source: National Natural Science Foundation of China

Award Identifier / Grant number: 61471224

Funding source: Shandong University of Science and Technology

  1. Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: This research was funded by the Shandong Natural Science Foundation, China (No. ZR2017MF070), Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents (No. 2016RCJJ012), National Natural Science Foundation of China (No. 61471224) and the domestic visiting scholar supported by Shandong University of Science and Technology.

  3. Conflict of interest statement: The authors declare no conflicts of interest regarding this article.

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Received: 2020-04-20
Accepted: 2020-07-27
Published Online: 2020-09-08

© 2020 the author(s), published by De Gruyter, Berlin/Boston

This work is licensed under the Creative Commons Attribution 4.0 International License.

Artikel in diesem Heft

  1. Frontmatter
  2. Amplifiers
  3. Editorial
  4. Erbium/Ytterbium-Doped Waveguide Amplifier (EYDWA) for extended reach of Wavelength Division Multiplexing based free space optics system (WDM/FSO)
  5. The effect of doping on the electrons and holes in quantum dot semiconductor optical amplifiers
  6. Performance analysis and parameter optimization of all-optical encryption using the FWM effect in semiconductor optical amplifier
  7. Total gain of InTlAsSb quantum dot structures
  8. Gain-forming effect on optical signal-to-noise ratio in Raman fiber amplifier
  9. Design of EDFA based 16 channel WDM system using counter directional high pump power
  10. Polarization rotation-based all-optical AND gate using single semiconductor optical amplifier and implementation of a majority gate
  11. Performance analysis on double-pass thulium-doped fiber amplifier for 16-channel WDM system at S-band
  12. Design of optical packet switch in presence of dispersion compensation and amplifier noise
  13. Alternative method of implementation of all-optical NOR and NAND gates using quantum-dot semiconductor optical amplifiers in non-interferometer structure
  14. Detectors
  15. A long-reach radio over free space optics (Ro-FSO) system using hybrid orthogonal frequency division multiplexing (OFDM)-multibeam concept with enhanced detection
  16. BER performance analysis of FSO using hybrid-SIM technique with APD receiver over weak and strong turbulence channels
  17. High-speed and long-reach PON employing PM-DQPSK signal and coherent receiver
  18. Devices
  19. Multi-Layer Graded-Index Planar Structure for Coarse WDM Demultiplexing
  20. Photonic Crystal-Based All-Optical Half Adder with High Contrast Ratio
  21. Distributed Feedback Laser (DFB) for Signal Power Amplitude Level Improvement in Long Spectral Band
  22. Performance analysis of carrier depletion silicon PIN phase shifter
  23. Design of Optical 4 × 2 Encoder Using Cross Layered Chalcogenide2D-PC Resonator
  24. 1 × 2 plasmonic wavelength demultiplexer using rectangular MIM waveguide
  25. Compact and efficient PC-based directional coupler all-optical switch
  26. All-optical integrated 2-to-4 decoder and 1-to-4 demultiplexer circuit with enable using SOA based MZI
  27. All optical half subtractor based on threshold switching and beams interference mechanisms
  28. An All Optical Photonic Crystal Based XOR Gate for BPSK Signals
  29. Four bits data sequence generators based ytterbium doped fiber amplifiers for upgrading maximum Q factor and minimum BER
  30. Design and optimization of all-optical demultiplexer using photonic crystals for optical computing applications
  31. Hybrid buffer‐based optical packet switch with negative acknowledgment for multilevel data centers
  32. Application of photonic crystal based nonlinear ring resonators for realizing all optical 3-to-8 decoder
  33. Power conversion with complete photonic band gap in magneto-photonic crystal slab based on cerium-substituted yttrium iron garnet
  34. Performance comparison of all-optical logic gates using electro-optic effect in MZI-based waveguide switch at 1.46 µm
  35. Modelling and analysis of chirped long-period grating inscribed in a planer optical waveguide structure for sensing applications
  36. Comparative study of all-optical INVERTER and BUFFER gates using MZI structure
  37. Design of multiplexing circuit using electro-optic effect based optical waveguides
  38. Performance enhancement of ultra-dense WDM over FSO hybrid optical link by incorporating MIMO technique
  39. A novel proposal based on 2D linear resonant cavity photonic crystals for all-optical NOT, XOR and XNOR logic gates
  40. All optical NAND/NOR and majority gates using nonlinear photonic crystal ring resonator
  41. Proposed model of all optical reversible and irreversible modules on a single photonic circuit
  42. A photonic crystal based de-multiplexer with uniform channel spacing
  43. An all optical photonic crystal half adder suitable for optical processing applications
  44. Modelling of symmetrical quadrature optical ring resonator with four different topologies and performance analysis using machine learning approach
  45. Effect of misalignment on coupling efficiency in laser diode to single-mode circular core graded-index fiber coupling via cylindrical microlens on the fiber tip
  46. A critical review of optical switches
  47. An ultra-dense spacing-based PON by incorporating dual drive Mach–Zehnder modulator for comb generation
  48. Logic gates based on optical transistors
  49. Compact and ultrafast all optical 1-bit comparator based on wave interference and threshold switching methods
  50. A high speed all optical half adder using photonic crystal based nonlinear ring resonators
  51. Ultrafast all optical XOR gate using photonic crystal-based nonlinear ring resonators
  52. Investigating the performance of all-optical AND logic gate based on FWM effect in SOA at low power
  53. Nonlinear optical decoder based on photonic quasi crystal ring resonator structure
  54. Optical data center switches design and analysis
  55. Hybrid buffer and AWG based add-drop optical packet switch
  56. Solitons based optical packet switch analysis
  57. A photonic transmission link with enhanced dynamic range by incorporating phase shifters in dual drive dual parallel Mach–Zehnder modulator
  58. Using nonlinear ring resonators for designing an all optical comparator
  59. All optical half subtractor based on linear photonic crystals and phase shift keying technique
  60. Multi-input single-output (MISO) all optical logic (ALG) AND/NOR gate using FWM in dispersion compensation fibers in Mach-Zehnder configuration (DCF-MZI)
  61. Wavelength and throughput tuning of FORR-based optical filter using Sagnac effect
  62. Performance Enhancement of Encoding–Decoding Multidiagonal and Walsh Hadamard Codes for Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) Utilizing Dispersion Compensated Fiber
  63. Impact Analysis of the Number of Core on Hexagonal Multicore Fibre
  64. Effect of OPC on Fiber Nonlinearities for Dense Soliton Optical Communication Medium
  65. Sensing of Illegal Drugs by Using Photonic Crystal Fiber in Terahertz Regime
  66. On characteristic behavior and flattened chromatic dispersion properties of bent photonic crystal fibers
  67. Ultra high birefringent dispersion flattened fiber in terahertz regime
  68. Structural dependence of transmission characteristics for photonic crystal fiber with circularly distributed air-holes
  69. Numerical analysis of photonic crystal fibre with high birefringence and high nonlinearity
  70. Exploiting higher-order mode dispersion of bend M-type chalcogenide fiber in mid-IR supercontinuum generation
  71. Design of optoelectronic oscillator based on multiple-length single mode fiber and chirped fiber Bragg grating
  72. Modulation instability in nonlinear chiral fiber
  73. High birefringence and broadband dispersion compensation photonic crystal fiber
  74. Design and analysis of highly nonlinear, low dispersion AlGaAs-based photonic crystal fiber
  75. Highly negative dispersion compensating fiber with low third order dispersion
  76. Dispersion properties of single-mode optical fibers in telecommunication region: poly (methyl methacrylate) (PMMA) versus silica
  77. Influence of Kerr nonlinearity on group delay and modal dispersion parameters of single-mode graded index fibers: evaluation by a simple but accurate method
  78. Highly birefringent photonic crystal fiber with D-shaped air holes for terahertz (THz) application
  79. Simulation and analysis of ultra-low material loss of single-mode photonic crystal fiber in terahertz (THz) spectrum for communication applications
  80. Investigation of radiation induced luminescence with modulated signal transmission in optical fiber
  81. Design and analysis of uncoupled heterogeneous trench-assisted multi-core fiber (MCF)
  82. Simulative study of raised cosine impulse function with Hamming grating profile based Chirp Bragg grating fiber
  83. Highly Efficient Solar Energy Conversion Using Graded-index Metamaterial Nanostructured Waveguide
  84. Chaotic Synchronization of Mutually Coupled Lasers with Another Laser and Its Encoding Application in Secret Communication
  85. Passively Femtosecond Mode-Locked Erbium-Doped Fiber Oscillator with External Pulse Compressor for Frequency Comb Generation
  86. Conventional band demultiplexer with high quality factor and transmission power based on four optimized shaped photonic crystal resonators
  87. Different modulation schemes for direct and external modulators based on various laser sources
  88. Third order intermodulation and third order intercept in a directly modulated Fabry–Perot laser diode
  89. Evaluation of quantum dot light-emitting diodes synchronization under optically feedback
  90. Laser diode to single-mode graded index fiber coupling via cylindrical microlens on the fiber tip: evaluation of coupling efficiency by ABCD matrix formalism
  91. Enhanced Performance Analysis of 10 Gbit/s–10 GHz OFDM-Based Radio over FSO Transmission System Incorporating ODSB and OSSB Modulation Schemes
  92. An Ultra-compact Plasmonic Modulator Using Elasto-optic Effect and Resonance Phenomena
  93. Performance Comparison of Free-Space Optical (FSO) Communication Link Under OOK, BPSK, DPSK, QPSK and 8-PSK Modulation Formats in the Presence of Strong Atmospheric Turbulence
  94. Model for Performance Improvement of Blocking Probability in GMPLS Networks
  95. Study on P2P Service Bearer Method for Passive Optical Network for Long Distance and Wide Access
  96. Physical layer impairment-aware ant colony optimization approach in WDM network
  97. Analysis of Laser Linewidth on the Performance of Direct Detection OFDM Based Backhaul and Backbone Networks
  98. Radio over fiber based signal transport schemes for emerging mobile fronthaul networks – a review
  99. A Comparative Study of Performances Between the WDM PON System and the CWDM PON System in an Optical Access Network
  100. Beam divergence and operating wavelength bands effects on free space optics communication channels in local access networks
  101. Proactive link handover deploying coordinated transmission for indoor visible light communications (VLC) networks
  102. Optimized Dynamic Bandwidth Allocation Algorithm for Optical Access Networks
  103. Packet Blocking Performance of Cloud Computing Based Optical Data Centers Networks under Contention Resolution Mechanisms
  104. Optimization of an EYDWA Amplifier Parameters for a Gigabit Passive Optical Network (GPON)
  105. Research on Power Optimization Based on Adaptive Passive Optical Networks
  106. Towards cloud transport using IP-multiservices access network (MSAN)
  107. Enhanced redirection strategy for peer to peer services in high-speed and large-capacity ethernet passive optical networks
  108. Transmission challenges in metropolitan area optical networks
  109. Performance evaluation of a multihop WDM network with share-per-node L-WIXC architecture
  110. Performance analysis of hybrid optical amplifiers for multichannel wavelength division multiplexed (WDM) optical networks
  111. Time-domain Measurement and Analysis of Differential Mode Delay and Modal Bandwidth of Graded-Index Multimode Fiber in SDM Networks
  112. Seven-channel 1 Gbps TWDM coexistence architecture supporting 65 Gbps optical link for next-generation passive optical network 2–based FTTX access networks
  113. Link failure recovery using p-cycles in wavelength division multiplex (WDM) mesh networks
  114. Cascadability analysis of WDM recirculating loop buffer-based switch in optical data networks
  115. Evolution of optical networks: from legacy networks to next-generation networks
  116. A novel framework for content connectivity through optical data centers
  117. Performance of different hybrid dispersion compensation modules (DCMs) in long reach ultra dense WDM passive optical networks
  118. Performance investigation of PM-based wavelength remodulation scheme in bidirectional TWDM-PON
  119. Physical layer analysis of optical wireless data centers
  120. Novel approach to jointly optimize working and spare capacity of survivable optical networks
  121. A QoS provisioning architecture of fiber wireless network based on XGPON and IEEE 802.11ac
  122. Radio over fiber on gigabit passive optical network using QPSK modulation scheme
  123. Blocking performance of optically switched data networks
  124. Devices, communication techniques and networks for all optical communication: research issues
  125. Design and investigation of N1-class next-generation passive optical network-2 (NG-PON2) coexistence architecture in the presence of Kerr effect and four-wave mixing (FWM) for fiber to the home (FTTX) access networks
  126. Improved algorithm for enhance robustness of IPTV based on GEPON
  127. Simultaneous distribution of wired and two 2 × 2 MIMO wireless OFDM signals over an integrated RoF-PON system
  128. Analyzing optical TDMA to mitigate interference in downlink LiFi optical attocell networks
  129. Light fidelity optical network a comparative performance evaluation
  130. Theory of chaos synchronization and quasi-period synchronization of an all optic 2n-D LAN
  131. Performance of high scalability hybrid system of 10G-TDM-OCDMA-PON based on 2D-SWZCC code
  132. Performance analysis of APD and PIN diode with and without EDFA in GPON
  133. Improved Performance Investigation of 10 Gb/s–10 GHz 4-QAM Based OFDM-Ro-FSO Transmission Link
  134. Feasibility Analysis of Optical Wireless Communication for Indian Tropical and Subtropical Climates
  135. 40 Gb/s High-speed mode-division multiplexing transmission employing NRZ modulation format
  136. Performance Analysis of Shift ZCC Codes and Multi Diagonal Codes in 100 Gbps MDM-FSO System
  137. Combined Envelope Scaling with Modified SLM Method for PAPR Reduction in OFDM-Based VLC Systems
  138. Empirical Evaluation of High-speed Cost-effective Ro-FSO System by Incorporating OCDMA-PDM Scheme under the Presence of Fog
  139. Satellite-to-Ground FSO System Based on Multiaperture Receivers as an Optimization Solution for Strong Turbulence and Fog Conditions
  140. Performance analysis of NRZ and RZ variants for FSO communication system under different weather conditions
  141. Free space optics communication system design using iterative optimization
  142. Optical wireless systems with ASK & PSK using coupler-based delay line filter
  143. Probing of nonlinear impairments in long range optical transmission systems
  144. Design and Investigation of Free Space Optical System for Diverse Atmospheric Transmission Windows
  145. The performance comparison of hybrid WDM/TDM, TDM and WDM PONs with 128 ONUs
  146. Performance evaluation of a multiple optical link FSO–FSO
  147. Analysis the flat gain/noise figure using RAMAN-Reflective Semiconductor Hybrid Optical Amplifier in C + L + U triple band for super dense wavelength division multiplexing system
  148. Design improvement to reduce noise effect in CDMA multiple access optical systems based on new (2-D) code using spectral/spatial half-matrix technique
  149. High-speed signal processing and wide band optical semiconductor amplifier in the optical communication systems
  150. 2 × 20 Gbit/s OFDM-based FSO transmission system for HAP-to-ground links incorporating mode division multiplexing with enhanced detection
  151. Radio-over-fiber front-haul link design using optisystem
  152. A 2 × 20 Gbps hybrid MDM-OFDM–based high-altitude platform-to-satellite FSO transmission system
  153. Analysis of hybrid integrated-alternate mark inversion (I-AMI) modulation and symmetrical-symmetrical-post (SSP) dispersion compensation technique in single-tone radio over fiber (RoF) system
  154. Peak to average power ratio (PAPR) reduction in filter bank multicarrier (FBMC) and orthogonal frequency division multicarrier (OFDM) based visible light communication systems
  155. Development and performance improvement of a novel zero cross-correlation code for SAC-OCDMA systems
  156. Comparative analysis of SISO and wavelength diversity-based FSO systems at different transmitter power levels
  157. Effect of adverse weather conditions and pointing error on the performance of 2-D WH/TS OCDMA over FSO link
  158. Performance of LED for line-of-sight (LoS) underwater wireless optical communication system
  159. Underwater wireless optical communication: a case study of chlorophyll effect
  160. Subcarrier multiplexed radio over fiber system with optical single sideband modulation
  161. Performance investigation of free space optics link employing polarization division multiplexing and coherent detection-orthogonal frequency division multiplexing under different link parameters
  162. Performance analysis of FSO link under the effect of fog in Delhi region, India
  163. Design and analysis of full duplex RoF system with efficient phase noise cancellation from a coherent RoF system
  164. Mathematical modeling of optical impairments in DSP based WDM coherent system
  165. Analysis of 64 channels based IS-OWC system using different intereference reduction techniques
  166. Effects of local oscillator on the performance of DP-QPSK WDM system with channel spacing of 37.5 GHz
  167. Dual band radio-over-fibre millimetre–wave system utilizing optical frequency combs
  168. Full duplex dispersion compensating system based on chromatic dispersion in analog RoF links
  169. Performance enhancement of Raman + EYDFA HOA for UD-WDM system applications
  170. Crosstalk characterization in homogeneous multicore fiber using discrete changes model under bidirectional propagation
  171. Analysis three dispersion compensation techniques using DCF
  172. Electrocardiogram transmission over OFDM system
  173. A multilayers adaptive ALACO-OFDM for spectral efficiency improvement using PSO algorithm in visible light communication systems
  174. A comprehensive road map of modern communication through free-space optics
  175. Performance of orthogonal frequency division multiplexing based 60-GHz transmission over turbulent free-space optical link
  176. Design of 16 × 40 Gbps hybrid PDM-WDM FSO communication system and its performance comparison with the traditional model under diverse weather conditions of Bangladesh
  177. Next generation optical wireless communication: a comprehensive review
  178. A companding approach for PAPR suppression in OFDM based massive MIMO system
  179. Characterization of terrestrial FSO link performance for 850 and 1310 nm transmission wavelengths
  180. Analysis of nonlinear behavior of multimode spatial laser beams with high stability and coherence for medical applications
  181. Performance of a free space optical link employing DCO-OFDM modulated Gaussian-beam
  182. Nonlinear/dispersion compensation in dual polarization 128-QAM system incorporating optical backpropagation
  183. New encoding/decoding design of SAC-OCDMA system with fixed correlation zone code
  184. Theoretical investigation of multiple input–multiple output (MIMO) technique for line of sight (LoS) underwater wireless optical communications system
  185. Dimming controlled multi header pulse position modulation (MH-PPM) for visible light communication system
  186. 40 Gb/s wavelength division multiplexing-passive optical network (WDM-PON) for undersea wireless optical communication
  187. Analyzing of UVLC system considering the effect of water depth
  188. On the transmission of data packets through fiber-optic cables of uniform index
  189. Performance analysis of WDM free space optics transmission system using MIMO technique under various atmospheric conditions
  190. Review on nonlinearity effect in radio over fiber system and its mitigation
  191. Improving the optical link for UVLC using MIMO technique
  192. A review on signal generation techniques in radio over fiber systems
  193. FBMC OQAM: novel variant of OFDM
  194. A 120 Mbps WDM-based VLC system for implementation of Internet of Things
  195. Physical layer security analysis of a dual-hop hybrid RF-VLC system
  196. Application scheme and performance analysis of free space optical communication technology in INMARSAT
  197. Artificial intelligence based optical performance monitoring
  198. Mobility aware of WDM-based CMO OFDM communication system
  199. Design and performance analysis of spectral-efficient hybrid CPDM-CO-OFDM FSO communication system under diverse weather conditions
  200. An approach to ensure joint illumination & communication performance of a forward error corrected indoor visible light communication (VLC) system in presence of ambient light interference
  201. A Large-Capacity Optical Switch Design for High-Speed Optical Data Centers
  202. Performance Analysis of OWC Using NOP Technique
  203. Performance Evaluation of a Hybrid Buffer-Based Optical Packet Switch Router
  204. Modeling C2 n by Inclusion of Rainfall Parameter and Validate Modified Log Normal and Gamma-Gamma Model on FSO Communication Link
  205. Enhancement of reliability and security in spatial diversity FSO-CDMA wiretap channel
  206. FSO-Based Analysis of LTE-A MAC Protocols to Achieve Improved QoS
  207. Dynamic routing and wavelength assignment for efficient traffic grooming
  208. High Birefringence and Negative Dispersion Based Modified Decagonal Photonic Crystal Fibers: A Numerical Study
  209. Impact of Pointing Error on the BER Performance of an OFDM Optical Wireless Communication Link over Turbulent Condition
  210. A receiver intensity for Super Lorentz Gaussian beam (SLG) propagation via the moderate turbulent atmosphere using a novelty mathematical model
  211. Performances of BICM-ID system using CRSC code in optical transmissions
  212. 128-QAM dual-polarization chaotic long-haul system performance evaluation
  213. Suppression of nonlinear noise in a high-speed optical channel with variable dispersion compensation
  214. Radio over fiber (RoF) link modelling using cross term memory polynomial
  215. An investigation of 16-QAM signal transmission over turbulent RoFSO link modeled by gamma–gamma distribution
  216. Design of 320 Gbps hybrid AMI-PDM-WDM FSO link and its performance comparison with traditional models under diverse weather conditions
  217. Non-linear companding scheme for peak-to-average power ratio (PAPR) reduction in generalized frequency division multiplexing
  218. Implementation of wavelet transform based non-Hermitian symmetry OFDM for indoor VLC system using Raspberry Pi
  219. PAPR reduction scheme for optical OFDM techniques
  220. Investigations with all optical sequential circuit at higher data rate
  221. Error performance analysis of optical communication over Lognormal-Rician turbulence channel using Gram-Charlier Series
  222. A simple but accurate method for prediction of splice loss in mono-mode dispersion shifted and dispersion flattened fibers in presence of Kerr nonlinearity
  223. Simulation modeling of free space optical communication system
  224. Digital predistortion of radio over fiber (RoF) link using hybrid Memetic algorithm
  225. Design of a low cost and power efficient 200/400 Gbps optical interconnect using DAC-less simplified PAM4 architecture
  226. Evaluation of inter-aircraft optical wireless communication system with different modulation formats
  227. Performance analysis of DP-MZM radio over fiber links against fiber impairments
https://doi.org/10.1515/joc-2020-0086
Schlagwörter für diesen Artikel
double weight multi-diagonal (DW-MD) code; spectral amplitude coding-optical code division multiple access (SAC-OCDMA); variable weight code; zero cross-correlation (ZCC) code
Creative Commons
BY 4.0

Artikel in diesem Heft

  1. Frontmatter
  2. Amplifiers
  3. Editorial
  4. Erbium/Ytterbium-Doped Waveguide Amplifier (EYDWA) for extended reach of Wavelength Division Multiplexing based free space optics system (WDM/FSO)
  5. The effect of doping on the electrons and holes in quantum dot semiconductor optical amplifiers
  6. Performance analysis and parameter optimization of all-optical encryption using the FWM effect in semiconductor optical amplifier
  7. Total gain of InTlAsSb quantum dot structures
  8. Gain-forming effect on optical signal-to-noise ratio in Raman fiber amplifier
  9. Design of EDFA based 16 channel WDM system using counter directional high pump power
  10. Polarization rotation-based all-optical AND gate using single semiconductor optical amplifier and implementation of a majority gate
  11. Performance analysis on double-pass thulium-doped fiber amplifier for 16-channel WDM system at S-band
  12. Design of optical packet switch in presence of dispersion compensation and amplifier noise
  13. Alternative method of implementation of all-optical NOR and NAND gates using quantum-dot semiconductor optical amplifiers in non-interferometer structure
  14. Detectors
  15. A long-reach radio over free space optics (Ro-FSO) system using hybrid orthogonal frequency division multiplexing (OFDM)-multibeam concept with enhanced detection
  16. BER performance analysis of FSO using hybrid-SIM technique with APD receiver over weak and strong turbulence channels
  17. High-speed and long-reach PON employing PM-DQPSK signal and coherent receiver
  18. Devices
  19. Multi-Layer Graded-Index Planar Structure for Coarse WDM Demultiplexing
  20. Photonic Crystal-Based All-Optical Half Adder with High Contrast Ratio
  21. Distributed Feedback Laser (DFB) for Signal Power Amplitude Level Improvement in Long Spectral Band
  22. Performance analysis of carrier depletion silicon PIN phase shifter
  23. Design of Optical 4 × 2 Encoder Using Cross Layered Chalcogenide2D-PC Resonator
  24. 1 × 2 plasmonic wavelength demultiplexer using rectangular MIM waveguide
  25. Compact and efficient PC-based directional coupler all-optical switch
  26. All-optical integrated 2-to-4 decoder and 1-to-4 demultiplexer circuit with enable using SOA based MZI
  27. All optical half subtractor based on threshold switching and beams interference mechanisms
  28. An All Optical Photonic Crystal Based XOR Gate for BPSK Signals
  29. Four bits data sequence generators based ytterbium doped fiber amplifiers for upgrading maximum Q factor and minimum BER
  30. Design and optimization of all-optical demultiplexer using photonic crystals for optical computing applications
  31. Hybrid buffer‐based optical packet switch with negative acknowledgment for multilevel data centers
  32. Application of photonic crystal based nonlinear ring resonators for realizing all optical 3-to-8 decoder
  33. Power conversion with complete photonic band gap in magneto-photonic crystal slab based on cerium-substituted yttrium iron garnet
  34. Performance comparison of all-optical logic gates using electro-optic effect in MZI-based waveguide switch at 1.46 µm
  35. Modelling and analysis of chirped long-period grating inscribed in a planer optical waveguide structure for sensing applications
  36. Comparative study of all-optical INVERTER and BUFFER gates using MZI structure
  37. Design of multiplexing circuit using electro-optic effect based optical waveguides
  38. Performance enhancement of ultra-dense WDM over FSO hybrid optical link by incorporating MIMO technique
  39. A novel proposal based on 2D linear resonant cavity photonic crystals for all-optical NOT, XOR and XNOR logic gates
  40. All optical NAND/NOR and majority gates using nonlinear photonic crystal ring resonator
  41. Proposed model of all optical reversible and irreversible modules on a single photonic circuit
  42. A photonic crystal based de-multiplexer with uniform channel spacing
  43. An all optical photonic crystal half adder suitable for optical processing applications
  44. Modelling of symmetrical quadrature optical ring resonator with four different topologies and performance analysis using machine learning approach
  45. Effect of misalignment on coupling efficiency in laser diode to single-mode circular core graded-index fiber coupling via cylindrical microlens on the fiber tip
  46. A critical review of optical switches
  47. An ultra-dense spacing-based PON by incorporating dual drive Mach–Zehnder modulator for comb generation
  48. Logic gates based on optical transistors
  49. Compact and ultrafast all optical 1-bit comparator based on wave interference and threshold switching methods
  50. A high speed all optical half adder using photonic crystal based nonlinear ring resonators
  51. Ultrafast all optical XOR gate using photonic crystal-based nonlinear ring resonators
  52. Investigating the performance of all-optical AND logic gate based on FWM effect in SOA at low power
  53. Nonlinear optical decoder based on photonic quasi crystal ring resonator structure
  54. Optical data center switches design and analysis
  55. Hybrid buffer and AWG based add-drop optical packet switch
  56. Solitons based optical packet switch analysis
  57. A photonic transmission link with enhanced dynamic range by incorporating phase shifters in dual drive dual parallel Mach–Zehnder modulator
  58. Using nonlinear ring resonators for designing an all optical comparator
  59. All optical half subtractor based on linear photonic crystals and phase shift keying technique
  60. Multi-input single-output (MISO) all optical logic (ALG) AND/NOR gate using FWM in dispersion compensation fibers in Mach-Zehnder configuration (DCF-MZI)
  61. Wavelength and throughput tuning of FORR-based optical filter using Sagnac effect
  62. Performance Enhancement of Encoding–Decoding Multidiagonal and Walsh Hadamard Codes for Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) Utilizing Dispersion Compensated Fiber
  63. Impact Analysis of the Number of Core on Hexagonal Multicore Fibre
  64. Effect of OPC on Fiber Nonlinearities for Dense Soliton Optical Communication Medium
  65. Sensing of Illegal Drugs by Using Photonic Crystal Fiber in Terahertz Regime
  66. On characteristic behavior and flattened chromatic dispersion properties of bent photonic crystal fibers
  67. Ultra high birefringent dispersion flattened fiber in terahertz regime
  68. Structural dependence of transmission characteristics for photonic crystal fiber with circularly distributed air-holes
  69. Numerical analysis of photonic crystal fibre with high birefringence and high nonlinearity
  70. Exploiting higher-order mode dispersion of bend M-type chalcogenide fiber in mid-IR supercontinuum generation
  71. Design of optoelectronic oscillator based on multiple-length single mode fiber and chirped fiber Bragg grating
  72. Modulation instability in nonlinear chiral fiber
  73. High birefringence and broadband dispersion compensation photonic crystal fiber
  74. Design and analysis of highly nonlinear, low dispersion AlGaAs-based photonic crystal fiber
  75. Highly negative dispersion compensating fiber with low third order dispersion
  76. Dispersion properties of single-mode optical fibers in telecommunication region: poly (methyl methacrylate) (PMMA) versus silica
  77. Influence of Kerr nonlinearity on group delay and modal dispersion parameters of single-mode graded index fibers: evaluation by a simple but accurate method
  78. Highly birefringent photonic crystal fiber with D-shaped air holes for terahertz (THz) application
  79. Simulation and analysis of ultra-low material loss of single-mode photonic crystal fiber in terahertz (THz) spectrum for communication applications
  80. Investigation of radiation induced luminescence with modulated signal transmission in optical fiber
  81. Design and analysis of uncoupled heterogeneous trench-assisted multi-core fiber (MCF)
  82. Simulative study of raised cosine impulse function with Hamming grating profile based Chirp Bragg grating fiber
  83. Highly Efficient Solar Energy Conversion Using Graded-index Metamaterial Nanostructured Waveguide
  84. Chaotic Synchronization of Mutually Coupled Lasers with Another Laser and Its Encoding Application in Secret Communication
  85. Passively Femtosecond Mode-Locked Erbium-Doped Fiber Oscillator with External Pulse Compressor for Frequency Comb Generation
  86. Conventional band demultiplexer with high quality factor and transmission power based on four optimized shaped photonic crystal resonators
  87. Different modulation schemes for direct and external modulators based on various laser sources
  88. Third order intermodulation and third order intercept in a directly modulated Fabry–Perot laser diode
  89. Evaluation of quantum dot light-emitting diodes synchronization under optically feedback
  90. Laser diode to single-mode graded index fiber coupling via cylindrical microlens on the fiber tip: evaluation of coupling efficiency by ABCD matrix formalism
  91. Enhanced Performance Analysis of 10 Gbit/s–10 GHz OFDM-Based Radio over FSO Transmission System Incorporating ODSB and OSSB Modulation Schemes
  92. An Ultra-compact Plasmonic Modulator Using Elasto-optic Effect and Resonance Phenomena
  93. Performance Comparison of Free-Space Optical (FSO) Communication Link Under OOK, BPSK, DPSK, QPSK and 8-PSK Modulation Formats in the Presence of Strong Atmospheric Turbulence
  94. Model for Performance Improvement of Blocking Probability in GMPLS Networks
  95. Study on P2P Service Bearer Method for Passive Optical Network for Long Distance and Wide Access
  96. Physical layer impairment-aware ant colony optimization approach in WDM network
  97. Analysis of Laser Linewidth on the Performance of Direct Detection OFDM Based Backhaul and Backbone Networks
  98. Radio over fiber based signal transport schemes for emerging mobile fronthaul networks – a review
  99. A Comparative Study of Performances Between the WDM PON System and the CWDM PON System in an Optical Access Network
  100. Beam divergence and operating wavelength bands effects on free space optics communication channels in local access networks
  101. Proactive link handover deploying coordinated transmission for indoor visible light communications (VLC) networks
  102. Optimized Dynamic Bandwidth Allocation Algorithm for Optical Access Networks
  103. Packet Blocking Performance of Cloud Computing Based Optical Data Centers Networks under Contention Resolution Mechanisms
  104. Optimization of an EYDWA Amplifier Parameters for a Gigabit Passive Optical Network (GPON)
  105. Research on Power Optimization Based on Adaptive Passive Optical Networks
  106. Towards cloud transport using IP-multiservices access network (MSAN)
  107. Enhanced redirection strategy for peer to peer services in high-speed and large-capacity ethernet passive optical networks
  108. Transmission challenges in metropolitan area optical networks
  109. Performance evaluation of a multihop WDM network with share-per-node L-WIXC architecture
  110. Performance analysis of hybrid optical amplifiers for multichannel wavelength division multiplexed (WDM) optical networks
  111. Time-domain Measurement and Analysis of Differential Mode Delay and Modal Bandwidth of Graded-Index Multimode Fiber in SDM Networks
  112. Seven-channel 1 Gbps TWDM coexistence architecture supporting 65 Gbps optical link for next-generation passive optical network 2–based FTTX access networks
  113. Link failure recovery using p-cycles in wavelength division multiplex (WDM) mesh networks
  114. Cascadability analysis of WDM recirculating loop buffer-based switch in optical data networks
  115. Evolution of optical networks: from legacy networks to next-generation networks
  116. A novel framework for content connectivity through optical data centers
  117. Performance of different hybrid dispersion compensation modules (DCMs) in long reach ultra dense WDM passive optical networks
  118. Performance investigation of PM-based wavelength remodulation scheme in bidirectional TWDM-PON
  119. Physical layer analysis of optical wireless data centers
  120. Novel approach to jointly optimize working and spare capacity of survivable optical networks
  121. A QoS provisioning architecture of fiber wireless network based on XGPON and IEEE 802.11ac
  122. Radio over fiber on gigabit passive optical network using QPSK modulation scheme
  123. Blocking performance of optically switched data networks
  124. Devices, communication techniques and networks for all optical communication: research issues
  125. Design and investigation of N1-class next-generation passive optical network-2 (NG-PON2) coexistence architecture in the presence of Kerr effect and four-wave mixing (FWM) for fiber to the home (FTTX) access networks
  126. Improved algorithm for enhance robustness of IPTV based on GEPON
  127. Simultaneous distribution of wired and two 2 × 2 MIMO wireless OFDM signals over an integrated RoF-PON system
  128. Analyzing optical TDMA to mitigate interference in downlink LiFi optical attocell networks
  129. Light fidelity optical network a comparative performance evaluation
  130. Theory of chaos synchronization and quasi-period synchronization of an all optic 2n-D LAN
  131. Performance of high scalability hybrid system of 10G-TDM-OCDMA-PON based on 2D-SWZCC code
  132. Performance analysis of APD and PIN diode with and without EDFA in GPON
  133. Improved Performance Investigation of 10 Gb/s–10 GHz 4-QAM Based OFDM-Ro-FSO Transmission Link
  134. Feasibility Analysis of Optical Wireless Communication for Indian Tropical and Subtropical Climates
  135. 40 Gb/s High-speed mode-division multiplexing transmission employing NRZ modulation format
  136. Performance Analysis of Shift ZCC Codes and Multi Diagonal Codes in 100 Gbps MDM-FSO System
  137. Combined Envelope Scaling with Modified SLM Method for PAPR Reduction in OFDM-Based VLC Systems
  138. Empirical Evaluation of High-speed Cost-effective Ro-FSO System by Incorporating OCDMA-PDM Scheme under the Presence of Fog
  139. Satellite-to-Ground FSO System Based on Multiaperture Receivers as an Optimization Solution for Strong Turbulence and Fog Conditions
  140. Performance analysis of NRZ and RZ variants for FSO communication system under different weather conditions
  141. Free space optics communication system design using iterative optimization
  142. Optical wireless systems with ASK & PSK using coupler-based delay line filter
  143. Probing of nonlinear impairments in long range optical transmission systems
  144. Design and Investigation of Free Space Optical System for Diverse Atmospheric Transmission Windows
  145. The performance comparison of hybrid WDM/TDM, TDM and WDM PONs with 128 ONUs
  146. Performance evaluation of a multiple optical link FSO–FSO
  147. Analysis the flat gain/noise figure using RAMAN-Reflective Semiconductor Hybrid Optical Amplifier in C + L + U triple band for super dense wavelength division multiplexing system
  148. Design improvement to reduce noise effect in CDMA multiple access optical systems based on new (2-D) code using spectral/spatial half-matrix technique
  149. High-speed signal processing and wide band optical semiconductor amplifier in the optical communication systems
  150. 2 × 20 Gbit/s OFDM-based FSO transmission system for HAP-to-ground links incorporating mode division multiplexing with enhanced detection
  151. Radio-over-fiber front-haul link design using optisystem
  152. A 2 × 20 Gbps hybrid MDM-OFDM–based high-altitude platform-to-satellite FSO transmission system
  153. Analysis of hybrid integrated-alternate mark inversion (I-AMI) modulation and symmetrical-symmetrical-post (SSP) dispersion compensation technique in single-tone radio over fiber (RoF) system
  154. Peak to average power ratio (PAPR) reduction in filter bank multicarrier (FBMC) and orthogonal frequency division multicarrier (OFDM) based visible light communication systems
  155. Development and performance improvement of a novel zero cross-correlation code for SAC-OCDMA systems
  156. Comparative analysis of SISO and wavelength diversity-based FSO systems at different transmitter power levels
  157. Effect of adverse weather conditions and pointing error on the performance of 2-D WH/TS OCDMA over FSO link
  158. Performance of LED for line-of-sight (LoS) underwater wireless optical communication system
  159. Underwater wireless optical communication: a case study of chlorophyll effect
  160. Subcarrier multiplexed radio over fiber system with optical single sideband modulation
  161. Performance investigation of free space optics link employing polarization division multiplexing and coherent detection-orthogonal frequency division multiplexing under different link parameters
  162. Performance analysis of FSO link under the effect of fog in Delhi region, India
  163. Design and analysis of full duplex RoF system with efficient phase noise cancellation from a coherent RoF system
  164. Mathematical modeling of optical impairments in DSP based WDM coherent system
  165. Analysis of 64 channels based IS-OWC system using different intereference reduction techniques
  166. Effects of local oscillator on the performance of DP-QPSK WDM system with channel spacing of 37.5 GHz
  167. Dual band radio-over-fibre millimetre–wave system utilizing optical frequency combs
  168. Full duplex dispersion compensating system based on chromatic dispersion in analog RoF links
  169. Performance enhancement of Raman + EYDFA HOA for UD-WDM system applications
  170. Crosstalk characterization in homogeneous multicore fiber using discrete changes model under bidirectional propagation
  171. Analysis three dispersion compensation techniques using DCF
  172. Electrocardiogram transmission over OFDM system
  173. A multilayers adaptive ALACO-OFDM for spectral efficiency improvement using PSO algorithm in visible light communication systems
  174. A comprehensive road map of modern communication through free-space optics
  175. Performance of orthogonal frequency division multiplexing based 60-GHz transmission over turbulent free-space optical link
  176. Design of 16 × 40 Gbps hybrid PDM-WDM FSO communication system and its performance comparison with the traditional model under diverse weather conditions of Bangladesh
  177. Next generation optical wireless communication: a comprehensive review
  178. A companding approach for PAPR suppression in OFDM based massive MIMO system
  179. Characterization of terrestrial FSO link performance for 850 and 1310 nm transmission wavelengths
  180. Analysis of nonlinear behavior of multimode spatial laser beams with high stability and coherence for medical applications
  181. Performance of a free space optical link employing DCO-OFDM modulated Gaussian-beam
  182. Nonlinear/dispersion compensation in dual polarization 128-QAM system incorporating optical backpropagation
  183. New encoding/decoding design of SAC-OCDMA system with fixed correlation zone code
  184. Theoretical investigation of multiple input–multiple output (MIMO) technique for line of sight (LoS) underwater wireless optical communications system
  185. Dimming controlled multi header pulse position modulation (MH-PPM) for visible light communication system
  186. 40 Gb/s wavelength division multiplexing-passive optical network (WDM-PON) for undersea wireless optical communication
  187. Analyzing of UVLC system considering the effect of water depth
  188. On the transmission of data packets through fiber-optic cables of uniform index
  189. Performance analysis of WDM free space optics transmission system using MIMO technique under various atmospheric conditions
  190. Review on nonlinearity effect in radio over fiber system and its mitigation
  191. Improving the optical link for UVLC using MIMO technique
  192. A review on signal generation techniques in radio over fiber systems
  193. FBMC OQAM: novel variant of OFDM
  194. A 120 Mbps WDM-based VLC system for implementation of Internet of Things
  195. Physical layer security analysis of a dual-hop hybrid RF-VLC system
  196. Application scheme and performance analysis of free space optical communication technology in INMARSAT
  197. Artificial intelligence based optical performance monitoring
  198. Mobility aware of WDM-based CMO OFDM communication system
  199. Design and performance analysis of spectral-efficient hybrid CPDM-CO-OFDM FSO communication system under diverse weather conditions
  200. An approach to ensure joint illumination & communication performance of a forward error corrected indoor visible light communication (VLC) system in presence of ambient light interference
  201. A Large-Capacity Optical Switch Design for High-Speed Optical Data Centers
  202. Performance Analysis of OWC Using NOP Technique
  203. Performance Evaluation of a Hybrid Buffer-Based Optical Packet Switch Router
  204. Modeling C2 n by Inclusion of Rainfall Parameter and Validate Modified Log Normal and Gamma-Gamma Model on FSO Communication Link
  205. Enhancement of reliability and security in spatial diversity FSO-CDMA wiretap channel
  206. FSO-Based Analysis of LTE-A MAC Protocols to Achieve Improved QoS
  207. Dynamic routing and wavelength assignment for efficient traffic grooming
  208. High Birefringence and Negative Dispersion Based Modified Decagonal Photonic Crystal Fibers: A Numerical Study
  209. Impact of Pointing Error on the BER Performance of an OFDM Optical Wireless Communication Link over Turbulent Condition
  210. A receiver intensity for Super Lorentz Gaussian beam (SLG) propagation via the moderate turbulent atmosphere using a novelty mathematical model
  211. Performances of BICM-ID system using CRSC code in optical transmissions
  212. 128-QAM dual-polarization chaotic long-haul system performance evaluation
  213. Suppression of nonlinear noise in a high-speed optical channel with variable dispersion compensation
  214. Radio over fiber (RoF) link modelling using cross term memory polynomial
  215. An investigation of 16-QAM signal transmission over turbulent RoFSO link modeled by gamma–gamma distribution
  216. Design of 320 Gbps hybrid AMI-PDM-WDM FSO link and its performance comparison with traditional models under diverse weather conditions
  217. Non-linear companding scheme for peak-to-average power ratio (PAPR) reduction in generalized frequency division multiplexing
  218. Implementation of wavelet transform based non-Hermitian symmetry OFDM for indoor VLC system using Raspberry Pi
  219. PAPR reduction scheme for optical OFDM techniques
  220. Investigations with all optical sequential circuit at higher data rate
  221. Error performance analysis of optical communication over Lognormal-Rician turbulence channel using Gram-Charlier Series
  222. A simple but accurate method for prediction of splice loss in mono-mode dispersion shifted and dispersion flattened fibers in presence of Kerr nonlinearity
  223. Simulation modeling of free space optical communication system
  224. Digital predistortion of radio over fiber (RoF) link using hybrid Memetic algorithm
  225. Design of a low cost and power efficient 200/400 Gbps optical interconnect using DAC-less simplified PAM4 architecture
  226. Evaluation of inter-aircraft optical wireless communication system with different modulation formats
  227. Performance analysis of DP-MZM radio over fiber links against fiber impairments
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