Silicon photonics multi-function integrated optical circuit with hybrid III-V photodiode for miniaturized fiber optic gyroscope applications

We present a silicon photonics multi-function integrated optical circuit (Si-MIOC) with a hybridintegrated III-V photodiode (PD) designed for miniaturized interferometric fiber optic gyroscope (IFOG) applications. The Si-MIOC integrates key IFOG components—including phase modulators, power couplers, and polarization filters—onto a single chip, while replacing the traditional Germanium PD with a back-illuminated III-V PD mounted atop a grating coupler. The PD-over-GC approach achieves high responsivity (∼0.9 A/W), extended optical bandwidth, and a bi-directional PER of 51.3 dB that significantly enhances the signal quality of the IFOG. A miniaturized thermoelectric cooler is introduced to stabilize chip temperature and the bias offset. Additionally, we demonstrate an avalanche photodiode (APD)-over-GC configuration to compensate for system insertion loss, achieving reasonable scale factor and angle random walk (ARW) even under low input power of -15 dBm. The SiMIOC-based IFOG achieves an ARW of 0.015°/√hr and a bias instability down to 0.08°/hr, while successfully detecting Earth's rotation. These results highlight a scalable and foundry-compatible approach to chip-scale IFOG systems for future inertial navigation technologies.