In this work, we study a system of coupled resonators with saturable gain and/or saturable absorption. When biased at a nonlinear exceptional point, the steady-state lasing frequency demonstrates a cubed-root response to frequency/refractive index perturbation, despite using a binary configuration. The magnitude of this response can be further enhanced by tuning the passive losses and saturable absorption in the system. These findings are first described through a coupled mode formalism and then verified by Steady-state Ab-initial Laser Theory.

We present the design of single-etch grating couplers implemented on native and a hybrid silicon nitride (SiN) photonic platform with amorphous silicon (α-Si) overlays, operating in the telecom waveband. The SiN-only grating coupler has a coupling loss of -3.6 dB and a 1-dB bandwidth of 37 nm. A hybrid α-Si-on-SiN platform yields improved coupling loss of -1.4 dB and -1 dB for uniform and subwavelength grating apodized designs, respectively.

The realization of broadband all-optical wavelength converters and frequency synthesizers represents a key element for the development of next-generation optical communications systems. In this regard, the use of intermodal nonlinear processes in integrated waveguides has recently attracted significant interest for all-optical processing applications. Here, we present our recent results on the development of integrated and broadband wavelength converters based on the use of the Bragg scattering intermodal four-wave mixing effect in a silicon-rich silicon nitride platform.

Nonlinear optical dynamics of a microring modulator are studied using a comprehensive model capturing the coupled effects of thermal self-heating, two-photon absorption, and free carrier dispersion. The model is experimentally verified and predicts power-dependent static and dynamic performance.