Abstract: The disclosure demonstrates n-doped resistive heaters in silicon waveguides showing photoconductive effects with high responsivities on the order of 100 mA/W. These photoconductive heaters, integrated into microring resonator (MRR)-based filters, can be used to automatically tune and stabilize the filters' resonance wavelength to the input laser-wavelength. This is achieved without requiring dedicated defect implantations, additional material depositions, dedicated photodetectors, or optical power tap-outs. Series-coupled higher-order MRR-based filters can be automatically tuned by sequentially aligning the resonance of each MRR to the laser-wavelength by using photoconductive heaters to monitor the light intensity in each MRR. Embodiments allow for the automatic wavelength stabilization of MRR-based optical circuits.

Abstract: An optical device includes first and second waveguide phase arms each having optically coupled parallel sections of waveguides, the parallel sections of each one of the waveguide phase arms being dissimilar to reduce crosstalk. The device further includes a tunable element for applying a phase shift to an optical signal traversing the first phase arm. The waveguides of the parallel sections may have dissimilar dimensions, e.g. may vary in width, thickness, or both. The waveguides adjacent the tunable element may be suspended and/or underetched to improve thermal isolation and accordingly reduce power consumption of the optical device.