On Optimum Enumerative Sphere Shaping Blocklength at Different Symbol Rates for the Nonlinear Fiber Channel

TL;DR

This paper investigates the effectiveness of short-blocklength enumerative sphere shaping in fiber-optic communication, demonstrating a 0.9 dB SNR gain at 56 GBd that diminishes at higher symbol rates and spans.

Contribution

It identifies the optimal blocklength for enumerative sphere shaping at different symbol rates in nonlinear fiber channels, highlighting conditions for maximum SNR improvement.

Findings

0.9 dB SNR gain at 56 GBd with short-blocklength shaping

Gain diminishes at higher symbol rates and multiple spans

Optimal blocklength depends on symbol rate and channel conditions

Abstract

We show that a 0.9 dB SNR improvement can be obtained via short-blocklength enumerative sphere shaping for single-span transmission at 56 GBd. This gain vanishes for higher symbol rates and a larger number of spans.