Enhanced linear and nonlinear optical phase response of AlGaAs microring resonators

We have constructed and characterized several optical microring resonators with scale sizes of the order of $10 \mathit{\mu }\mathrm{m}$. These devices are intended to serve as building blocks for engineerable linear and nonlinear photonic media. Light is guided vertically by an epitaxially grown structure and transversely by deeply etched air-clad sidewalls. We report on the spectral phase transfer characteristics of such resonators. We also report the observation of a $\pi$-rad Kerr nonlinear phase shift accumulated in a single compact ring resonator evidenced by all-optical switching between output ports of a resonator-enhanced Mach–Zehnder interferometer.