Ultralow-crosstalk, strictly non-blocking microring-based optical switch

We report on the first monolithically integrated microring-based optical switch in the switch-and-select architecture. The switch fabric delivers strictly non-blocking connectivity while completely canceling the first-order crosstalk. The 4 × 4 switching circuit consists of eight silicon microring-based spatial (de-)multiplexers interconnected by a Si/SiN dual-layer crossing-free central shuffle. Analysis of the on-state and off-state power transfer functions reveals the extinction ratios of individual ring resonators exceeding 25 dB, leading to switch crosstalk suppression of up to over 50 dB in the switch-and-select topology. Optical paths are assessed, showing losses as low as 0.1 dB per off-resonance ring and 0.5 dB per on-resonance ring. Photonic switching is actuated with integrated micro-heaters to give an ∼24 GHz passband. The fully packaged device is flip-chip bonded onto a printed circuit board breakout board with a UV-curved fiber array.