We propose a new method for the simultaneous interrogation of conventional two-beam interferometers and Bragg grating sensors. The technique employs an unbalanced Mach-Zehnder interferometer illuminated by a single low-coherence source, which acts as a wavelength-tunable source for the grating and as a path-matched f ilter for the Fizeau interferometer, thus providing a high phase resolution output for each sensor. The grating sensor demonstrates a dynamic strain resolution of ~0.05 µe/vHz at 20 Hz, while the interferometric phase resolution is better than 1 mrad/vHz at 20 Hz, corresponding to an rms mirror displacement of 0.08 nm.
Bibliographical note© 1995 The Optical Society. This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/ol/abstract.cfm?URI=ol-20-11-1340. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
- simultaneous interrogation
- conventional two-beam interferometers
- Bragg grating sensors
- unbalanced Mach-Zehnder interferometer
- single low-coherence source