SFDM/CWDM of Hollow-Core Photonic Crystal Fiber Based Etalon Strain Sensors with Long Cavity Lengths

摘要

Spatial-frequency division multiplexing (SFDM)/coarse-wavelength division multiplexing (CWDM) of in-line fiber-optic etalon (ILFE) strain sensors, formed by a section of hollow-core photonic crystal fiber (HCPCF), is reported in this paper, for the first time to the best of our knowledge. Due to the low thermal expansion coefficient of HCPCF, such a strain sensor is much less sensitive to temperature change compared with conventional ILFE sensors. In the meanwhile, as the transmission loss of HCPCF is very low, the cavity length of the HCPCF sensor can be much longer than existing ILFEs, making it ideal for use in SFDM and offering great potential to realize multiplexing of a very large number of ILFE sensors. A SFDM/CWDM system with four HCPCF-based ILFE strain sensors is demonstrated and the experimental results show that a strain accuracy of ±5μεcan be achieved.