The static thermal sensitivity of the optical phase in bare and jacketed fibers has been studied both analytically and experimentally. Taking into account the exact fiber composition and geometry, the strains have been determined from the thermally induced stresses using the appropriate boundary conditions, and the resulting phase shift has been calculated. The results of this analysis are found to be in agreement with experimental results obtained from measurements employing a Mach-Zehnder fiber interferometer.
N. Lagakos, J. A. Bucaro, and J. Jarzynski, "Temperature-induced optical phase shifts in fibers," Appl. Opt. 20, 2305-2308 (1981)