Regular Perturbation and Achievable Rates of Space-Division Multiplexed Optical Channels

TL;DR

This paper models and analyzes the achievable information rates in space-division multiplexed optical fibers using a correlated rotation-and-additive noise model, demonstrating significant gains with joint processing.

Contribution

Introduces a CRAN model for SDM optical channels and computes achievable rates using particle filters, highlighting benefits of joint processing over separate processing.

Findings

Joint processing improves rate by 0.5 bits/s/Hz for S=2 modes.

Joint processing reduces power requirement by 1.4 dB.

CRAN model captures phase noise, mode rotation, and additive noise effects.

Abstract

Regular perturbation is applied to space-division multiplexing (SDM) on optical fibers and motivates a correlated rotation-and-additive noise (CRAN) model. For S spatial modes, or 2S complex-alphabet channels, the model has 4S(S+1) hidden independent real Gauss-Markov processes, of which 2S model phase noise, 2S(2S-1) model spatial mode rotation, and 4S model additive noise. Achievable information rates of multi-carrier communication are computed by using particle filters. For S=2 spatial modes with strong coupling and a 1000 km link, joint processing of the spatial modes gains 0.5 bits/s/Hz/channel in rate and 1.4 dB in power with respect to separate processing of 2S complex-alphabet channels without considering CRAN.