Temperature-insensitive displacement sensor based on high-birefringence photonic crystal fiber loop mirror

A temperature-insensitive displacement sensor based on high-birefringence photonic crystal fiber loop mirror (Hi-Bi PCFLM) is proposed. Through the measurement of transmission peak wavelength of the Hi-Bi PCFLM, this displacement sensor quantifies the free end displacement of a uniform-strength cantilever beam, on which part of Hi-Bi PCF is pasted. We have theoretically analyzed its operation principle, which is validated by our experimental results. This displacement sensor has the sensitivity of 0.28286 nm/mm and 0.27024 nm/mm over a range from -21 mm to 21 mm for two adjacent peak wavelengths, respectively. Experimental observation indicates that this sensor has good stability through a temperature range from 40 °C to 109.5 °C.