Grating based interferometric devices on a silicon photonic platform

Abstract

Abstract This work presents a class of integrated photonic interferometers based on the Michelson architecture, implemented on a silicon-on-insulator platform operating at 1.5–1.6  $$\mu$$ m. The devices combine directional couplers, subwavelength gratings (SWG), and Bragg grating reflectors. Furthermore, by cascading and branching multiple Michelson units, we demonstrate more complex interferometric structures for specialized applications. The integration of SWG sections enables fine-tuning of the effective refractive index and enhances sensitivity for sensing applications through increased evanescent field interaction with the surrounding medium. Selected designs are fabricated and experimentally characterized. Fabricated Fabry-Pérot devices achieve quality factors exceeding 6,500, while Michelson-based structures exhibit extinction ratios up to 43 dB, demonstrating good qualitative agreement with simulations. Finally, we explore potential applications optical filtering, sensing, and electro-optic modulation.