Title :
Multi-Modulus Blind Equalizations for Coherent Quadrature Duobinary Spectrum Shaped PM-QPSK Digital Signal Processing
Author :
Junwen Zhang ; Jianjun Yu ; Nan Chi ; Ze Dong ; Jianguo Yu ; Xinying Li ; Li Tao ; Yufeng Shao
Author_Institution :
Dept. of Commun. Sci. & Eng., Fudan Univ., Shanghai, China
Abstract :
A novel digital signal processing (DSP) scheme for quadrature duobinary (QDB) spectrum shaped polarization multiplexed quadrature phase shift keying (PM-QPSK) based on multi-modulus blind equalizations (MMBE) is proposed and demonstrated with both simulation and experimental results. The key algorithms for this novel digital signal processing scheme include the cascaded multi-modulus algorithm (CMMA) for blind polarization de-multiplexing, multi-modulus QPSK partitioning frequency offset estimation (FOE) and two stage carrier phase recovery (CPR) with maximum likelihood phase estimation. The final signal is detected by maximum-likelihood sequence detection (MLSD) for data BER measurement. It shows that CMMA have better frequency response performance compared with CMA for noise compression. The performances of FOE and CPR are also investigated with different spectrum shaping bandwidth, group size and laser linewidth. Finally, the feasibility of the proposed digital signal processing scheme is demonstrated by the experiment of 112 Gb/s QDB spectrum shaped PM-QPSK signal with a 25 GHz bandwidth waveshaper for Nyquist WDM channels.
Keywords :
blind equalisers; demultiplexing; error statistics; frequency estimation; frequency response; maximum likelihood estimation; quadrature phase shift keying; wavelength division multiplexing; CPR; FOE; MLSD; Nyquist WDM channels; QDB; bandwidth 25 GHz; bit rate 112 Gbit/s; blind polarization demultiplexing; carrier phase recovery; cascaded multi-modulus algorithm; coherent quadrature duobinary spectrum shaped PM-QPSK; data BER measurement; digital signal processing; frequency offset estimation; frequency response; group size; laser linewidth; maximum likelihood phase estimation; maximum likelihood sequence detection; multimodulus blind equalizations; polarization multiplexed quadrature phase shift keying; spectrum shaping bandwidth; Bandwidth; Bit error rate; Digital signal processing; Optical filters; Optical noise; Phase shift keying; Signal to noise ratio; Duobinary shaping; PM-QPSK; QPSK partitioning; multi-modulus equalizations;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2013.2242429
