On-chip phase interrogator based on a silicon Michelson interferometer for wavelength-multiplexed FBG sensors

The feasibility of demodulating fiber Bragg grating (FBG) accelerometers using a Michelson interferometer (MI) based on a silicon-on-insulator (SOI) platform, in conjunction with phase demodulation techniques, is experimentally demonstrated. An on-chip MI structure is obtained through the integration of a multimode interferometer (MMI) with waveguide Bragg gratings (WBGs). This on-chip MI exhibits an output spectral bandwidth of 14 nm and a free spectral range (FSR) of 0.84 nm. By employing thermal tuning of the on-chip MI, wavelength division multiplexing was implemented. This work employs phase generated carrier (PGC) demodulation techniques to achieve dynamic demodulation of fiber optic accelerometers (FOAs). The performance of the system is validated by comparing it with a commercial FBG interrogator. The system ultimately demonstrates a dynamic acceleration resolution of 0.204 <i>mg</i>/<i>Hz</i>.