Title :
Design of Polarization De-Multiplexer and PMD Compensator for 112 Gb/s Direct-Detect PDM RZ-DQPSK Systems
Author :
Shen, Yunfeng ; Liu, Xiumin ; Zhong, Shan ; Zong, Lei ; Veselka, John ; Kim, Peter ; Ferment, Joseph ; Sardesai, Harshad P.
Author_Institution :
Ciena Corp., Linthicum, MD, USA
Abstract :
The design of a polarization de-multiplexer and a polarization mode dispersion compensator (PMDC) for direct-detect polarization division multiplexed (PDM) return-to-zero differential quadrature phase shift keying (RZ-DQPSK) systems are studied in detail. The impact of polarization dependent loss is studied in polarization de-multiplexers with different error detection configurations for both bit-aligned and bit-interleaved PDM systems. The level of the clock frequency of the combined pulse train of the two polarizations is proposed as the error signal for the PMDC. It enables the PMDC to work in the cancellation mode. Two separate control loops are proposed for the polarization de-multiplexer and the PMDC to allow them to work independently. The DGD tolerances for the one-stage and two-stage PMDC are measured and discussed. Finally the glitch problem in the polarization tuning algorithm is studied. An advanced dithering algorithm and the corresponding architecture of the polarization controller are proposed to solve the glitch problem.
Keywords :
demultiplexing equipment; differential phase shift keying; light polarisation; multiplexing; optical communication equipment; optical control; optical design techniques; optical dispersion; optical losses; optical tuning; quadrature phase shift keying; DGD tolerances; bit rate 112 Gbit/s; bit-aligned PDM systems; bit-interleaved PDM systems; cancellation mode; clock frequency; combined pulse train; control loops; direct-detect PDM RZ-DQPSK systems; direct-detect polarization division multiplexing; dithering algorithm; error detection configurations; error signal; glitch problem; polarization controller; polarization demultiplexer; polarization dependent loss; polarization mode dispersion compensator; polarization tuning algorithm; return-to-zero differential quadrature phase shift keying; Adaptive optics; Crosstalk; Optical fibers; Optical noise; Optical polarization; Signal to noise ratio; Glitch problem; PMDC; RZ-DQPSK; polarization control; polarization dependent loss; polarization division multiplexed; tuning algorithm;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2010.2080352
