Fiber optic sensor with transmission/reflection analyzer

TLDR: In this article, a fiber optic sensor with a transmission/reflection analyzer for detection and localization of a perturbation that generates additional losses in the test fiber is presented.

Abstract: Fiber optic sensor with transmission/reflection analyzer for detection and localization of a perturbation that generates additional losses in the test fiber. The sensor includes a test fiber having a first port and a second port; a light source for producing a beam of light propagating along the test fiber; a fiber optic beamsplitter having a first port connected to the light source, a second port connected to the first port of the test fiber, and a third and a fourth port; a plurality of reflectors positioned along the test fiber and a plurality of loss-inducing members positioned along the test fiber, wherein said each of the reflectors is matched to each loss-inducing members, wherein at least one reflector is placed between each consecutive loss-inducing member; an optical reflection detector to receive a light flux, the optical reflection detector connected to the third port of optic beamsplitter, wherein the reflection detector is adapted to sense changes in the power of the light reflected from the reflectors; an optical transmission detector adapted to receive the light flux, connected to the second port of test fiber, said transmission detector being operable to sense changes in the power of the light transmitted through the test fiber; and a transmission/reflection analyzer connected to reflection and transmission detectors, said analyzer adapted to measure the value and identify the location of the disturbance along the test fiber by using a unique relation between transmitted and reflected powers for different locations of the disturbance along the test fiber.