A comparison of electrical and optical dispersion compensation for 111-Gbit/s POLMUX-RZ-DQPSK

In this paper, we experimentally investigate the tolerance of 111-Gb/s polarization multiplexed return-to-zero differential quadrature phase-shift keying (POLMUX-RZ-DQPSK) signals with respect to nonlinear impairments in a link with either (inline) optical or (receiver-side) electrical dispersion compensation. After transmission of more than 2000 km of LEAF, a comparable nonlinear tolerance is observed for both dispersion maps. However, we observe that in the presence of differential group delay (DGD) the nonlinear tolerance of the transmission link with in-line optical dispersion compensation is reduced significantly, whereas the nonlinear tolerance of the configuration with receiver-side dispersion compensation is virtually unaffected. © 2009 IEEE.