Low-Complexity Linewidth-Tolerant Carrier Phase Estimation for 64-QAM Systems Based on Constellation Transformation

A novel three-stage digital feed-forward carrier recovery algorithm based on the transformation of 64-QAM constellation into QPSK is proposed. For 1 dB penalty at BER=1e-2, it can tolerate a linewidth-times-symbol-rate product of 4.5e-5, making it possible to operate 32-Gbaud optical 64-QAM systems with current commercial tunable lasers

Coherent equalization versus direct detection for 111-Gb/s ethernet transport

We discuss coherent equalization to realize robust 111-Gb/s transmission. For 111-Gb/s POLMUX-RZDQPSK we experimentally show the advantage of coherent equalization over direction detection for compensation of both chromatic dispersion and differential group delay

Coherent equalization versus direct detection for 111-Gb/s ethernet transport

We discuss coherent equalization to realize robust 111-Gb/s transmission. For 111-Gb/s POLMUX-RZDQPSK we experimentally show the advantage of coherent equalization over direction detection for compensation of both chromatic dispersion and differential group delay

Carrier phase estimation for coherent equalization of 43-Gb/s POLMUX-NRZ-DQPSK transmission with 10.7-Gb/s NRZ neighbours

We show the influence of 10.7-Gb/s NRZ neighbors on 43-Gb/s polarization-multiplexed NRZ-DQPSK transmission combined with digital coherent equalization. The impact of XPM induced phase noise is reduced with an optimized carrier phase estimation (CPE) algorithm

Electrical PMD compensation in 43-Gb/s POLMUX-NRZ-DQPSK enabled by coherent detection and equalization

PMD compensation using coherent equalization is demonstrated experimentally. Using 43-Gb/s polarization-multiplexed NRZ-DQPSK, we show compensation of practically arbitrary amounts of DGD (>200ps) and CD with negligible penalty, even in the presence of PDL and SOPMD

Impairment tolerance of 111 Gbit/s POLMUX-RZ-DQPSK using a reduced complexity coherent receiver with a T-spaced equaliser

The tolerance to narrow spectral filtering in presence of chromatic dispersion is investigated for 111Gbit/s POLMUX-RZ-DQPSK. It is shown that the use of T-spaced equalisers is enabled by appropriate electrical filtering

Carrier phase estimation for coherent equalization of 43-Gb/s POLMUX-NRZ-DQPSK transmission with 10.7-Gb/s NRZ neighbours

We show the influence of 10.7-Gb/s NRZ neighbors on 43-Gb/s polarization-multiplexed NRZ-DQPSK transmission combined with digital coherent equalization. The impact of XPM induced phase noise is reduced with an optimized carrier phase estimation (CPE) algorithm