High-Sensitivity Compact Fiber-Optic Coherent Micro-Vibration Sensing System Based on Silicon Photonics Integrated Optical Phase Detection

A high performance and miniaturized microvibration sensing system is highly desirable for satellite payload platforms. In this paper, a compact micro-vibration sensing system assisted with silicon photonic integrated circuit is presented and experimentally demonstrated. A dedicated silicon photonic integrated circuit including IQ modulator and variable optical attenuators is designed and fabricated for high-sidebandsuppression-ratio frequency shifting and high-extinction-ratio pulse generation as the carrier for signals detection. A push-pull fiber optic micro-vibration sensor is designed for micro-vibration sensing and an integrated coherent receiver is applied for demodulation of sensing signals. This integrated scheme achieves higher average sensitivity of 49.44 dB re rad/g with the sensor's size of 25 × 25 × 25 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and lower noise level of -135 dB re g<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /Hz.