Investigation of analog signal distortion introduced by a fiber phase sensitive amplifier

TL;DR

This paper numerically investigates how a fiber phase sensitive amplifier introduces distortion to analog signals in microwave photonics links, comparing different modulation and gain saturation scenarios to identify conditions minimizing nonlinearity.

Contribution

It provides a validated numerical model for analyzing analog signal distortion in PSAs and explores conditions to reduce nonlinearity effects, including the impact of gain saturation.

Findings

Distortion varies with modulation type and PSA gain saturation.

A perfectly linear modulator reduces signal nonlinearity.

Certain conditions can minimize PSA-induced nonlinearity.

Abstract

We numerically simulate the distortion of an analog signal carried in a microwave photonics link containing a phase sensitive amplifier (PSA), focusing mainly on amplitude modulation format. The numerical model is validated by comparison with experimental measurements. By using the well known two-tone test, we compare the situations in which a standard intensity modulator is used with the one where a perfectly linear modulator would be employed. We also investigate the role of gain saturation on the nonlinearity of the PSA. Finally, we establish the conditions, in which the signal nonlinearity introduced by the PSA itself can be extremely small.