Competence Center for Specialty Optical Fibers

A Fabry-Pérot microcavity tip temperature sensor based on a special design double-cladding optical fiber is proposed. The produced fiber has pure silica core and outer cladding and a silica ring doped with phosphorous. The whole ring region is removed by chemical etching post-processing. Consequently, light will be guided in the core region. In a first step, the double-cladding optical fiber is spliced to single mode fiber. Afterwards, the tip is etched in a solution of 48% hydrofluoric acid. The inner cladding will be etched faster, and the core becomes suspended and surrounded by air. The Fabry-Pérot microcavity tip sensor is subjected to temperature, and a linear sensitivity of 14.6 pm/°C is obtained.