Digital back-propagation for spectrally efficient
WDM 112 Gbit/s PM m-ary QAM transmission

Abstract

We report the performance of coherently-detected nine-channel WDM transmission over high dispersion fibers, using polarization multiplexed m-ary quadrature amplitude modulation (m=4, 16, 64, 256) at 112 Gbit/s. Compensation of fiber nonlinearities via digital back-propagation enables up to 10 dB improvement in maximum transmittable power and ~8 dB Qeff improvement which translates to a nine-fold enhancement in transmission reach for PM-256QAM, where the largest improvements are associated with higher-order modulation formats. We further demonstrate that even under strong nonlinear distortion the transmission reach only reduces by a factor of ~2.5 for a 2 unit increase in capacity (log2m) when full band DBP is employed, in proportion to the required back-to-back OSNR.

Nonlinear Penalties in Dynamic Optical Networks Employing Autonomous Transponders

“…2b) for 256QAM traffic. The ROADM spacing for 16 and 64QAM signals were scaled in proportion (approximately) to their required OSNR levels under linear transmission [7]. The two cases correspond to the red and blue boxes in Table I, respectively.…”

“…400 Gb/s) to some routes. The consequent increase in required OSNR will either reduce reach or necessitate the use of digital back-propagation (DBP) to mitigate channel nonlinearity [6][7][8].…”

Design and performance evaluation of an OPC device using a dual-pump polarization-independent FOPA

“…In this context, a renewed interest for nonlinear compensation has led to several demonstrations both in the digital and the optical domains [2][3][4] . Optical phase conjugation (OPC) is a well-known technique allowing inverting the signal spectrum, therefore enabling the compensation of dispersion and Kerr effect accumulated through propagation by further transmission of the conjugated signal.…”

Optical and Digital Phase Conjugation Techniques for Fiber Nonlinearity Compensation

“…In recent years, extensive efforts in attempting to surpass the Kerr nonlinearity limit have been made through several nonlinearity compensation techniques and nonlinear transmission schemes [2]. Digital-back-propagation (DBP) [3] is an effective nonlinearity compensation method, which removes the inter signal nonlinear distortion by inverting the distorted signal at the receiver digitally. However, DBP has some serious challenges, limiting its success in practice so far.…”