BIREFRINGENT OPTICAL TEMPERATURE SENSOR WITH ADJUSTABLE TEMPERATURE SENSITIVITY

摘要

An optical temperature sensor for use in a temperature detector system having at least two birefringent crystal elements arranged in tandem. A collimated broad band light source is transmitted via a fiber optic cable, a polarizer to a first birefringent crystal element. The first crystal element decomposes the light wave into first and second orthogonally polarized waves and transmits the wave components to a second birefringent crystal element. The linearly polarized waves propagate through the birefringent crystals, and the environmental temperature introduces a temperature dependent phase shift between the two polarized waves. The light waves exit the second crystal to a second polarizer producing a modulated light spectrum. A focusing element collects the light and transmits it down another fiber optic cable. The cable transmits the light to an opto-electronic interface where the fringe pattern is extracted and a computer compatible signal is generated for a CPU. The CPU performs a Fourier transform on the fringe pattern, where the phase term for a selected frequency is the measure of the environmental temperature experienced by the birefringent crystals.