Quantum theory of Synchronously Pumped type I Optical Parametric Oscillators: characterization of the squeezed supermodes

TL;DR

This paper develops a quantum model for synchronously pumped type I optical parametric oscillators, introducing supermodes to simplify the analysis of their complex multimode dynamics and characterizing their squeezing properties.

Contribution

It presents a novel supermode-based framework for analyzing SPOPOs, enabling simplified understanding of their quantum squeezing behavior and spectral characteristics.

Findings

Derived a general squeezing spectrum expression for SPOPOs.

Characterized the spectral and temporal shapes of squeezed supermodes.

Calculated the oscillation threshold for SPOPOs.

Abstract

Quantum models for synchronously pumped type I optical parametric oscillators (SPOPO) are presented. The study of the dynamics of SPOPOs, which typically involves millions of coupled signal longitudinal modes, is significantly simplified when one considers the ?supermodes?, which are independent linear superpositions of all the signal modes diagonalizing the parametric interaction. In terms of these supermodes the SPOPO dynamics becomes that of about a hundred of independent, single mode degenerate OPOs, each of them being a squeezer. One derives a general expression for the squeezing spectrum measured in a balanced homodyne detection experiment, valid for any temporal shape of the local oscillator. Realistic cases are then studied using both analytical and numerical methods: the oscillation threshold is derived, and the spectral and temporal shapes of the squeezed supermodes are characterized.