Gary F. Sinclair

Effect of self- and cross-phase modulation on photon pairs generated by spontaneous four-wave mixing in integrated optical waveguides

A novel time-domain approach using the momentum operator is used to model spontaneous four-wave mixing in a lossless nonlinear waveguide. The effects of self- and cross-phase modulation on the photon-pair production rate and heralded photon purity are investigated. We show that in the special case where only one half of the photon-pair state is filtered that the generation rate and purity of the heralded photons are unmodified by the presence of self- and cross-phase modulation. The significance of this special case arises when we consider heralded single-photon sources, where future schemes are likely to only filter the herald photon to ensure a high heralding efficiency is maintained.

On-chip quantum interference with heralded photons from two independent micro-ring resonator sources in silicon photonics

High visibility on-chip quantum interference among indistinguishable single-photons from multiples sources is a key prerequisite for integrated linear optical quantum computing. Resonant enhancement in micro-ring resonators naturally enables brighter, purer and more indistinguishable single-photon production without any tight spectral filtering. The indistinguisha-bility of heralded single-photons from multiple micro-ring resonators has not been measured in any photonic platform. Here, we report on-chip indistinguishability measurements of heralded single-photons generated from independent micro-ring resonators by using an on-chip Mach-Zehnder interferometer and spectral demultiplexer. We measured the raw heralded two-photon interference fringe visibility as 72 ± 3%. This result agrees with our model, which includes device imperfections, spectral impurity and multi-pair emissions. We identify multi-pair emissions as the main factor limiting the nonclassical interference visibility, and show a route towards achieving near unity visibility in future experiments.

An on-chip homodyne detector for generating random numbers

The homodyne detector is a primitive element in many quantum optics experiments. It is primarily a characterization device, used for measuring the quantum state of the electromagnetic field[1]. Quantum integrated photonics[2], in which optical sources, circuits, and detectors are monolithically integrated on a semi-conductor chip, provides a compact, scalable, platform in which to implement quantum devices like the homodyne detector.

Comparison of photon pair generation in a-Si:H and c-Si microring resonators

We generate photon pairs via SFWM in hydrogenated amorphous silicon microring resonators, and compare the behavior to crystalline silicon.