Silicon photonics multi-function integrated optical circuit for miniaturized fiber optic gyroscope

Interferometric fiber optic gyroscope (IFOG) is advantageous for inertial navigation due to its high reliability as a solid-state technology with no moving parts. The size, weight, power, and cost of IFOG can be improved by employing photonic integration technology. Here, by leveraging the foundry-enabled silicon photonics platform, we demonstrate a silicon multi-function integrated optical circuit (Si-MIOC) with a fingertip size that can easily interfaces with light source and fiber coil to perform a tactical-grade gyroscope (0.1 °/hr bias instability). This achievement comes from the pros of high-index-contrast silicon waveguide that enables high polarization extinction ratio of > 60 dB and high electro-optic efficiency in silicon phase modulator, while the cons of the signature lead to non-negligible optical back-reflection at silicon/fiber interfaces and generate spurious bias voltage offset at the gyroscope outputs. Nevertheless, the results of earth rotation measurement and Allan deviation analysis confirmed that Si-MIOC based IFOG is a promising angular sensor and can be utilized to construct a compact and low-cost inertial measurement unit.