Phase Noise Influence in Coherent Optical OFDM Systems with RF Pilot Tone: Digital IFFT Multiplexing and FFT Demodulation
-
Gunnar Jacobsen,
,
Tianhua Xu,
Abstract
We present a comparative study of the influence of dispersion induced phase noise for CO-OFDM systems using Tx channel multiplexing and Rx matched filter (analogue hardware based); and digital FFT multiplexing/IFFT demultiplexing techniques (software based). An RF carrier pilot tone is used to mitigate the phase noise influence. From the analysis, it appears that the phase noise influence for the two OFDM implementations is very similar. The software based system provides a method for a rigorous evaluation of the phase noise variance caused by Common Phase Error (CPE) and Inter-Carrier Interference (ICI) and this, in turns, leads to a BER specification. Numerical results focus on a CO-OFDM system with 1 GS/s QPSK channel modulation. Worst case BER results are evaluated and compared to the BER of a QPSK system with the same capacity as the OFDM implementation. Results are evaluated as a function of transmission distance, and for the QPSK system the influence of equalization enhanced phase noise (EEPN) is included. For both types of systems, the phase noise variance increases significantly with increasing transmission distance. An important and novel observation is that the two types of systems have very closely the same BER as a function of transmission distance for the same capacity. For the high capacity QPSK implementation, the increase in BER is due to EEPN, whereas for the OFDM approach it is due to the dispersion caused walk-off of the RF pilot tone relative to the OFDM signal channels. For a total capacity of 400 Gbit/s, the transmission distance to have the BER < 10−4 is less than 277 km.
For an RF pilot located in the center of the OFDM band in a CO-OFDM implementation with n-level PSK channel modulation the current results suggest that the walk-off effect is equivalent to the EEPN impact in a single channel n-level PSK system with the same capacity. This observation is important for future design of coherent long-range systems since it shows that there is a free choice between CO-OFDM and a high capacity nPSK implementation at least as long as the phase noise influence is concerned.
©[2012] by Walter de Gruyter Berlin Boston
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- Triplexer Monitor Design for Failure Detection in FTTH System
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- Phase Noise Influence in Coherent Optical OFDM Systems with RF Pilot Tone: Digital IFFT Multiplexing and FFT Demodulation
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Articles in the same Issue
- Masthead
- Throughput of Coded Optical CDMA Systems with AND Detectors
- Thin-Layer Optical Filter for Specific Areas of Visible Spectrum Based on 1D Photonic Crystal Structure
- Design and Simulation of Photonic Crystal Based Optical Filter of Specified Flat-top Pass Bandwidth
- Eigenmodes of Simplified Square-latticed Photonic Crystal Waveguides
- A Vibration Sensor System based on Distributed Feedback Fiber Lasers and Digital Phase Generated Carrier Demodulation
- RZ-DPSK Modulation Signal Generation using Only One Mach-Zehnder Modulator for 48 × 40 Gbit/s Ultra Long Haul DWDM Transmission
- A Design of Sensor Network for Remote Communication Based on GPON
- Wavelength Rotation Graph Algorithm Based on Physical Impairment Constraints in Optical Networks
- A Novel Architecture Scheme for OFDM Passive Optical Network with Source-free ONUs
- Feed-Forward Optical Carrier Recovery for QAM Coherent Optical Receivers
- Triplexer Monitor Design for Failure Detection in FTTH System
- A Novel Scheme of Generating Optical Packets in OLS System
- Phase Noise Influence in Coherent Optical OFDM Systems with RF Pilot Tone: Digital IFFT Multiplexing and FFT Demodulation
- Investigation of Pre-, Post- and Symmetric-Dispersion Compensation Techniques (DCF) using Different Modulation Formats over High-Speed Optical Link
