Multimode fiber Fabry-Perot interferometer tip sensor

We demonstrate an optical Fabry-Perot interferometer fiber tip sensor based on an etched end of multimode fiber filled with ultraviolet adhesive. The fiber device is miniature and robust, in a convenient reflection mode of operation, has a high temperature sensitivity of 213 pm/°C within the range from 55 to 85°C, a good refractive index sensitivity of ∼−73.54 nm/RIU (refractive index unit) within the range from 1.332 to 1.372, and a high gas pressure sensitivity of −40.94nm/MPa. This device has a high potential in monitoring extreme environment of high temperature and pressure when Sapphire fiber and stable high temperature glue are employed.