Optical Phase-Shift Interrogation Method With a Single-Ended PM-PCF Sensor

We propose an optical phase-shift interrogation method that uses optical interferometric signals from a polarization-maintaining photonic crystal fiber (PM-PCF). The interference signal can be achieved using two different polarized beams, which propagate through the PM-PCF and the reflection coating. Since the PM-PCF has negligible thermal sensitivity, it is suitable for remote temperature-insensitive strain sensors when it is single-ended with reflection coating. Because the PM-PCF has a much lower wavelength-strain sensitivity compared with normal polarization-maintaining fibers, we developed an alternative optical phase-shift interrogation method to detect tiny strain deviations below the resolution of optical spectrum analyzer. We also demonstrated dynamic strain measurement using a wavelength-swept laser source.