The Analysis of a Stabilized 1.5 Mach-Zehnder Interferometric Sensor with Enhanced Sensitivity and Common-Mode Compensation

Abstract : The design and construction of an active stabilization controller and its interface to an interferometric fiber optic sensor--the enhanced sensitivity, common-mode compensated 1.5 Mach-Zehnder is reported in this dissertation. The feasibility of employing this active stabilization circuit to maintain the operation of an enhanced sensitivity, common-mode compensated 1.5 Mach-Zehnder interferometer over the narrow operating range required for common- mode compensation and high sensitivity was demonstrated. Thus, a suitable means to minimize, even eliminate, the effects of environmental disturbances (common-mode and random) and to achieve maximum sensitivity and linearity in the presence of differential phase modulation was proven. This research shows that the incorporation of a controller into the fiber optic sensor can improve the performance of the sensor with electro-optic feedback over two orders of magnitude (100 times) more than without electro-optic feedback. More importantly, the fiber optic sensor exhibited nearly a full order of magnitude (10 times) improvements in sensitivity beyond the state-of-the-art performance reported to date for the conventional Mach-Zehnder optical circuit.