Photon pair generation in hydrogenated amorphous silicon microring resonators

TL;DR

This paper demonstrates photon pair generation in hydrogenated amorphous silicon microring resonators, revealing a high Kerr coefficient and power-dependent losses, with implications for optimizing device Q factors for efficient photon pair production.

Contribution

It provides the first measurement of the Kerr coefficient in a-Si:H microrings and analyzes how power-dependent losses affect photon pair generation efficiency.

Findings

Kerr coefficient of a-Si:H measured as 3.73 ± 0.25 × 10^{-17} m^2/W.

Loss in a-Si:H microrings scales linearly with power, not from two-photon absorption.

High Kerr coefficient benefits low-Q microrings; high-Q devices experience suppressed photon pair rates.

Abstract

We generate photon pairs in a-Si:H microrings using a CW pump, and find the Kerr coefficient of a-Si:H to be $3.73 \pm 0.25 \times 10^{-17}m^2/W$. By measuring the Q factor with coupled power we find that the loss in the a-Si:H micro-rings scales linearly with power, and therefore cannot originate from two photon absorption. Theoretically comparing a-Si:H and c-Si micro-ring pair sources, we show that the high Kerr coefficient of this sample of a-Si:H is best utilized for microrings with Q factors below $10^3$, but that for higher Q factor devices the photon pair rate is greatly suppressed due to the first order loss.