Ultimate Capacity of a Linear Time-Invariant Bosonic Channel

TL;DR

This paper calculates the maximum classical information capacity of a linear time-invariant bosonic channel with Gaussian noise, relevant for fiber-optic communications, and compares it with detection methods.

Contribution

It provides a general continuous-time formula for the ultimate capacity of such channels under power constraints, a novel theoretical result.

Findings

Derived the ultimate capacity formula for the channel

Compared capacity with heterodyne and homodyne detection

Applicable to fiber-optic communication regimes

Abstract

We determine the ultimate classical information capacity of a linear time-invariant bosonic channel with additive phase-insensitive Gaussian noise. This channel can model fiber-optic communication at power levels below the threshold for significant nonlinear effects. We provide a general continuous-time result that gives the ultimate capacity for such a channel operating in the quasimonochromatic regime under an average power constraint. This ultimate capacity is compared with corresponding results for heterodyne and homodyne detection over the same channel.