Multifunctional sensor system

Abstract

A multifunctional sensor system for an intrinsic type optical sensing fiber. A numerical aperture controlling optical input element for the excitation fiber may maximize the amount of sensing fiber modulated return light. The excitation fiber may be centered in a ring or linear array of return fibers, to inject excitation light into the return light poor center of the sensing fiber; and to capture return light from the return light rich outer parts of the sensing fiber. Tipping the return fibers with respect to the sensing fiber may increase their capture of high numerical aperture return light. The sizes and number of the adjacent ends of the excitation, return and sensing fibers may be selected to minimize the effects of any lateral displacement between the adjacent ends. The sensing fiber may generate both reference and sensor return light; and a ratiometric output signal may be derived from the reference and sensor return light which may be free of certain system errors. Ribbon-like sensor and sensing fibers may be provided; along with a transition fiber if the sensor and sensing fibers are of different sizes. An annular, possibly tapered, waveguide may be provided around the sensing fiber, to better capture the return light. The waveguide may either pass the target objective; or it may be hollow, and define a sample chamber for the target objective. The ends of the sensing fiber and/or the annular waveguide may be mirrored, to dramatically increase the output of return light, and thus, the sensitivity of the sensor system.