Photon pair generation via down-conversion in III-V semiconductor microrings: modal dispersion and quasi-phase matching

TL;DR

This paper analyzes how III-V semiconductor microring resonators can generate photon pairs efficiently through spontaneous parametric down-conversion, highlighting the role of modal dispersion and quasi-phase matching.

Contribution

It provides an analytic model for biphoton wave functions and characterizes squeezed states, including loss effects, for the first time in this context.

Findings

Conversion efficiency of 10^-5 at 39 MHz rate for 1 μW pump power

High levels of squeezing and pump depletion are possible

Potential for deterministic non-Gaussian state generation

Abstract

We explore how III-V semiconductor microring resonators can efficiently generate photon pairs and squeezed vacuum states via spontaneous parametric down-conversion by utilizing their built-in quasi phase matching and modal dispersion. We present an analytic expression for the biphoton wave function of photon pairs generated by weak pump pulses, and characterize the squeezed states that result under stronger pumping conditions. Our model includes loss, and captures the statistics of the scattered photons. A detailed sample calculation shows that for low pump powers conversion efficiencies of 10$^{-5}$, corresponding to a rate of $39$ MHz for a pump power of 1 $\mu$W, are attainable for rudimentary structures such as a simple microring coupled to a waveguide, in both the continuous wave and pulsed excitation regimes. Our results suggest that high levels of squeezing and pump depletion are attainable, possibly leading to the deterministic generation of non-Gaussian states.