Performance and Long-Term Reliability of Polarization-Maintaining Fiber Connectors for Fiber-Optic Current Sensors

The performance and long-term reliability of polarization-maintaining (PM) fiber-optic connectors is studied experimentally for use in interferometric fiber-optic current sensors. In particular, we investigate the effect of accelerated ageing and repeated open/close operations on the connectors' polarization extinction ratio (PER) and insertion loss between -40 and 80°C and determine the influence on sensor accuracy. The results show that PM connectors (FC/PC type with reduced mechanical tolerances for high PER) exhibit good repeatability and largely preserve their performance over extended periods of ageing. Nevertheless, the observed long-term changes in the temperature dependence of the PER can restrict the usability of these components in high-end sensor applications and call for alternative solutions.