A system has been developed to linearize the output of most interferometric optical sensors from DC to high frequency. The system employs a broad band light source with an unbalanced MachZehnder interferometer to cancel phase changes induced by the sensor. An analog circuit is employed to produce the phase tracking signal which is linearly proportional to sensor phase. The system has demonstrated a phase resolution of 1.920 when used to track an extrinsic Fabry-Perot strain sensor. This corresponds to a strain resolution of 0.35jie. Frequency response is estimated to be greater than 100kHz for the current system and above 100MHz for an integrated optic embodiment. In addition, the system is insensitive to polarization and intensity changes induced by source drift or lead fiber perturbations.

No abstract