Zhenshan Yang

Enhanced second-harmonic generation in AlGaAs microring resonators

Highly efficient second-harmonic generation can be achieved by harnessing resonance effects in microring resonator structures. We propose an angular quasi-phase-matching scheme based on the position dependence of polarization inside the ring resonator.

Spontaneous four-wave mixing in microring resonators

We consider spontaneous four-wave mixing in a microring resonator, presenting photon-pair generation rates and biphoton wave functions. We show how generation rates can be simply predicted from the performance of the device in the classical regime and that a wide variety of biphoton wave functions can be achieved by varying the pump pulse duration.

Stopping, storing, and releasing light in quantum-well Bragg structures

Stopping, storing and releasing of light in resonant photonic bandgap structures made from Bragg-spaced quantum wells is studied. The expected performance of almost ideal infinite systems is contrasted with that of existing structures.

Distortionless light pulse delay in quantum-well Bragg structures

We describe a reflection scheme that allows Bragg-spaced semiconductor quantum wells to be used to trap, store, and release light. We study the temporal and spectral distortion of delayed light pulses and show that this geometry allows multibit delays and offers a high degree of distortion compensation.

Generating entangled photons via enhanced spontaneous parametric downconversion in AlGaAs microring resonators.

Spontaneous parametric downconversion (SPDC) can be enhanced in double-channel side-coupled microring resonator structures, generating entangled photons spatially separated in different channels. The enhancement is even more drastic in single-channel side-coupled microring resonator structures, although the generated entangled photons are not spatially separated, and it might be most interesting to use a ring tuned for nondegenerate SPDC.

Increasing the delay-time--bandwidth product for microring resonator structures by varying the optical ring resonances.

We propose a scheme to increase the delay-time--bandwidth product for a periodic microring resonator structure in slowing or stopping light. The idea is based on the existence of a low group velocity and low dispersion region close to a band edge near a ring resonance. By putting different frequency components on resonance with different rings, one can drastically slow down the light without inducing large additional dispersive distortion.

Mechanism of all-optical spin-dependent polarization switching in Bragg-spaced quantum wells

The authors outline a microscopic theory of pump-induced anisotropy in the optical response of Bragg-spaced quantum wells (BSQWs). Their theory explains the manipulation of the band structure of the BSQWs by the pump through the microscopic interactions between excitons in the quantum wells. They apply their theory to understand the mechanism of an all-optical polarization switch implemented on a BSQW structure. They trace the relation between the strongly spin-dependent exciton-exciton interactions and the switching signal. Reasonably good agreement is found between their theoretical results and experimental data.

Ultra-low power frequency conversion in high-index glass micro ring resonators

We present the first demonstration of ultra-low power four-wave-mixing in a high-index glass micro-ring resonator (47.5 mum radius). By using a mW-level CW pump power we obtained an appreciable wavelength conversion in the C-band.

Integrated high order filters in AlGaAs waveguides with up to eight side-coupled racetrack microresonators

Side-coupled-integrated-spaced-sequence-of-resonators (SCISSORs) with many rings are important for controlling the behavior of light propagation. We show the linear performance of SCISSORs in high index-contrast AlGaAs in 1, 2, 4, and 8 ring configurations.

Stopping, storing and releasing light in quantum well Bragg structures

Stopping, storing and releasing of light in resonant photonic bandgap structures made from Bragg-spaced quantum wells is studied. The expected performance of almost ideal infinite systems is contrasted with that of existing structures.