Steady states of a chi-three parametric oscillator with coupled polarisations

TL;DR

This paper models the steady states of a coupled chi-three parametric oscillator system, revealing multiple thresholds, polarization rotations, and frequency shifts, with results aligning with recent experimental observations.

Contribution

It introduces a simple coupled model for polarization effects in microcavity parametric oscillators, identifying novel thresholds and polarization behaviors not seen in uncoupled systems.

Findings

Multiple steady states exist under continuous pumping.

Discontinuous thresholds produce finite output intensities.

Coupling causes polarization rotation and frequency shifts.

Abstract

Polarisation effects in the microcavity parametric oscillator are studied using a simple model in which two chi-three optical parametric oscillators are coupled together. It is found that there are, in general, a number of steady states of the model under continuous pumping. There are both continuous and discontinuous thresholds, at which new steady-states appear as the driving intensity is increased: at the continuous thresholds, the new state has zero output intensity, whereas at the discontinuous threshold it has a finite output intensity. The discontinuous thresholds have no analog in the uncoupled device. The coupling also generates rotations of the linear polarisation of the output compared with the pump, and shifts in the output frequencies as the driving polarisation or intensity is varied. For large ratios of the interaction between polarisations to the interaction within polarisations, of the order of 5, one of the thresholds has its lowest value when the pump is elliptically polarised. This is consistent with recent experiments in which the maximum output was achieved with an elliptically polarised pump.