Free spectral range optimization of return-to-zero differential phase-shift keyed demodulation in 40 Gbit/s nonlinear transmission.
For differential decoding, direct detection of DPSK signal needs a delay line interferometer with a free spectral range normally equal to the transmitted bit-rate. We numerically demonstrate that free spectral range optimization can increase tolerance to fiber Kerr nonlinearities for 40 Gbit/s RZ-DPSK transmission, especially for multi-format (RZ-DPSK and RZ-OOK) systems, in which Kerr nonlinearities is quite serious mainly due to cross-phase modulation. The optimal delay time of the delay line interferometer in DPSK signal demodulation is shorter than one bit-period. Joint optimization of free spectral range and optical filter bandwidth will further enhance system tolerance to nonlinear transmission.
State Key Laboratory of Advanced Optical Communication Systems & Networks, School of Electronics Engineering and Computer Science, Peking University, Beijing, 100871, China.
Xiaolin
X
Li
Fan
F
Zhang
Xiaoru
X
Zhang
Dechao
D
Zhang
Zhangyuan
Z
Chen
Anshi
A
Xu
D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D016247:Information Storage and Retrieval / Q000379:methods*; D008962:Models, Theoretical; D017711:Nonlinear Dynamics; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*