Enhanced optical communication and broadband sub-shot-noise interferometry with a stable free-running periodically-poled-KTiOPO4 squeezer

TL;DR

This paper demonstrates a stable, broadband, phase-squeezed optical source using PPKTP, achieving enhanced interferometric sensitivity and increased channel capacity in optical communication.

Contribution

It introduces a stable, free-running PPKTP-based optical parametric oscillator for broadband phase squeezing, improving interferometry and communication performance.

Findings

3.2 dB sensitivity enhancement in interferometry

Broadband squeezing over 20 MHz

Increased channel capacity beyond coherent communication

Abstract

An intrinsically stable type-I optical parametric oscillator was built with a periodically poled KTiOPO4 (PPKTP) crystal to generate a stable bright, continuous-wave, broadband phase-squeezed beam. A 3.2 dB sensitivity enhancement of optical interferometry was demonstrated on weak electrooptic modulation signals within a 20 MHz squeezing bandwidth. This also realized a channel capacity increase beyond that of coherent optical communication.