Fiber optic sensor for spatially separated elements in a system

摘要

A fiber optic sensor employs tapered fiber optics in a tapered gun barrel. The fiber optic sensor employs a single-mode optical fiber, a light source supplying light to the single-mode fiber and at least one tapered dual-mode optical fiber secured to the barrel in a longitudinal direction. The single-mode fiber is spliced to with an end of a proximal one of the dual-mode fibers for carrying the light signal. A partial reflector is inserted between the dual-mode fibers to partially reflect and partially transmit light. A reflector is coupled to a distal end the dual-mode fiber, at the open end of the muzzle of the gun, to reflect the transmitted light. A coupler couples the single-mode fiber to the proximal dual-mode fiber. A coherent multiplexer is connected to the coupler for receiving and multiplexing the reflected light. A processor is responsive to the multiplexer for processing the multiplexed sensing information. The dual-mode fiber is tapered inversely with respect to the tapered muzzle to simplify the processing function. When two or more dual-mode fibers are employed, an offset splice is provided between the dual-mode fibers. A method is also disclosed.