Temperature and Pressure Sensor Based on Polished Fiber-Optic Microcavity

A single-optic-fiber temperature and pressure sensor based on a side-polished optical fiber microcavity coated with a polydimethylsiloxane (PDMS) film has been proposed and fabricated. This sensor integrates two Mach-Zehnder interferometers (MZIs), where the first MZI is formed by path 1 in the inside coating, and the second MZI is constructed by path 1 and path 2 in the waist region. The formation mechanism of the dual MZIs is simulated by using the finite-difference beam propagation method, and the sensitivities of the dual MZIs are predicted by simulations. Experimental results indicate the temperature sensitivity of −1.19 nm/°C for the first MZI and pressure sensitivity of −3.96 nm/MPa for the second MZI, respectively. By monitoring the dual wavelength shifts corresponding to the dual MZIs, temperature and pressure can be simultaneously measured. Due to the good sensitivities, simple fabrication and robust structure, the proposed sensor shows promising potential for optofluidic sensing and ocean detection.