Reduced models and design principles for half-harmonic generation in synchronously-pumped optical parametric oscillators

TL;DR

This paper introduces simplified models for half-harmonic generation in synchronously-pumped optical parametric oscillators, capturing effects of nonlinearity, dispersion, and mismatch, with analytical and experimental validation.

Contribution

It presents novel reduced models covering different power regimes, providing analytical insights into pulse behavior and stability in these oscillators.

Findings

Models accurately predict pulse compression and operation regimes.

Analytical formulas match numerical and experimental data.

Different pulse shapes are characterized across power levels.

Abstract

We develop reduced models that describe half-harmonic generation in a synchronously-pumped optical parametric oscillator above threshold, where nonlinearity, dispersion, and group-velocity mismatch are all relevant. These models are based on (1) an eigenmode expansion for low pump powers, (2) a simulton-like sech-pulse ansatz for intermediate powers, and (3) dispersionless box-shaped pulses for high powers. Analytic formulas for pulse compression, degenerate vs. nondegenerate operation, and stability are derived and compared to numerical and experimental results.