title: Sensitivity enhancement of fiber loop cavity ring-down pressure sensor.
abstract: We present a theoretical and experimental study on sensitivity enhancement of a fiber-loop cavity ring-down pressure sensor. The cladding of the sensing fiber is etched in hydrofluoric acid solution to enhance its sensitivity. The experimental results demonstrate that the pressure applied on the sensing fiber is linearly proportional to the difference between the reciprocals of the ring-down time with and without pressure, and the relative sensitivity exponentially increases with decreasing the cladding diameter. When the sensing fiber is etched to 41.15 microm, its sensitivity is about 36 times that of nonetched fiber in the range of 0 to 32.5 MPa. The measured relative standard deviation of the ring-down time is about 0.15% and, correspondingly, the least detectable loss is about 0.00069 dB.
authors.affiliation: Institute of Optical Information Science and Technology, Shaanxi Key Laboratory of Optical Information Technology, School of Science, Northwestern Polytechnical University, Xi'an 710072, China.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Jiang
authors.forename: Dexing
authors.initials: D
authors.lastname: Yang
authors.forename: Daqing
authors.initials: D
authors.lastname: Tang
authors.forename: Jianlin
authors.initials: J
authors.lastname: Zhao