Reconfigurable hybrid silicon waveguide Bragg filter using ultralow-loss phase-change material

Abstract

Reconfigurable silicon photonic devices attract much research attention, and hybrid integration with tunable phase-change materials (PCMs) exhibiting large refractive index contrast between amorphous (Am) and crystalline (Cr) states is a promising way to achieve this goal. Here, we propose and numerically investigate a S b 2 S e 3 -Si hybrid waveguide Bragg filter operating in the telecom C-band on the silicon-on-insulator (SOI) platform. The proposed device consists of a Bragg grating (BG) with a thin top layer of ultralow-loss S b 2 S e 3 PCM interacting with evanescent field of the silicon waveguide mode. By harnessing the ultralow-loss and reversible index change of S b 2 S e 3 film, the spectral response of the hybrid BGs could be dynamically tuned. We also theoretically investigate the reversible phase transitions between Am and Cr states of S b 2 S e 3 film that could be attained by applying voltage pulses on the indium-tin-oxide (ITO) strip heater covered on S b 2 S e 3 film. Thermal simulations show that a 2 V (4.5 V) pulse with a duration of 400 ns (55 ns) applied to electric contacts would produce crystallization (or amorphization). The proposed structure may find great potential for on-chip phase tunable devices on a silicon platform.