Proposal and performance evaluation of an efficient RZ-DQPSK modulation scheme in all-optical OFDM transmission systems
Document Type
Article
Publication Date
9-1-2013
Abstract
A return-to-zero differential quadrature phase-shift keying (DQPSK) modulation scheme is proposed for all-optical orthogonal frequency-division multiplexing transmission systems. The system uses coupler-based inverse fast Fourier transform/fast Fourier transform to support a 700 km single-mode fiber link and a transmission rate of 40 Gb/s without any nonlinear compensation. The performance of the proposed system is evaluated using simulation and four performance measures are obtained, namely, the eye diagram, the eye-opening penalty (EOP), the power spectral broadening, and the bit error rate(BER). The effect of self-phase modulation is taken into account in the performance evaluation. In addition, the performance of the proposed system is compared to that of a traditional one adopting a non-return-to-zero DQPSK scheme. Our results reveal that the proposed system outperforms the traditional one in all four aforementioned performance measures, yet the spectral efficiency is almost preserved. Specifically, for an input average power of 12 dBm, a reduction in both the required optical-signal-to-noise ratio of about 4 dB (to achieve a BER of 10-6) and the EOP of about 5 dB are reported when adopting the proposed system, as compared to the traditional one.
Keywords
All-optical OFDM, Eye diagram, Fiber optic nonlinearity, Non-return-to-zero differential quadrature phase-shift keying (NRZ-DQPSK), Return-to-zero differential quadrature phase-shift keying (RZ-DQPSK), Self-phase modulation (SPM)
Divisions
fac_eng
Publication Title
IEEE/OSA Journal of Optical Communications and Networking
Volume
5
Issue
9
Publisher
Institute of Electrical and Electronics Engineers (IEEE)