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 Mach-Zehnder 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 1.92 degree(s) when used to track an extrinsic Fabry-Perot strain sensor. This corresponds to a strain resolution of 0.35 (mu) (epsilon) . Frequency response is estimated to be greater than 100 kHz for the current system and above 100 MHz for an integrated optic embodiment. In addition, the system is insensitive to polarization and intensity changes induced by source drift or lead fiber perturbations.

Date Published: 12 July 1993
PDF: 9 pages
Proc. SPIE 1918, Smart Structures and Materials 1993: Smart Sensing, Processing, and Instrumentation, (12 July 1993); doi: 10.1117/12.147975

Published in SPIE Proceedings Vol. 1918:
Smart Structures and Materials 1993: Smart Sensing, Processing, and Instrumentation
Richard O. Claus, Editor(s)