Optical-fiber thermal modulator

This paper describes a new device which utilizes the thermal sensitivity of optical fibers to modulate the phase of the light in an interferometric sensor. The purpose of the optical-fiber thermal modulator is to maintain the interferometer in its most sensitive (quadrature) condition, and it thus represents a potential replacement for the comparatively bulky piezoelectric transducers (PZT) customarily used. Shorter lengths of fiber and considerably lower voltages than are required for the piezoelectric devices produce phase shifts of many wavelengths in the optical-fiber thermal modulator.