Multi-channel curvature sensor based on fiber bending loss wavelength and SPR

摘要

Fiber Bragg gratings and interferometric curvature sen-sors are easily disturbed by axial strain and temperature, and cascaded multi-channel curvature sensing is difficult. In this letter, a curvature sensor based on fiber bending loss wavelength and the surface plasmon resonance (SPR) mech-anism is proposed, which is insensitive to axial strain and temperature. In addition, fiber bending loss valley wave-length demodulation curvature improves the accuracy of bending loss intensity sensing. Experiments show that the bending loss valley of single-mode fiber with different cut-off wavelengths has different working bands which is combined with a plastic-clad multi-mode fiber SPR curvature sensor to realize a wavelength division multiplexing multi-channel curvature sensor. The bending loss valley wavelength sensi-tivity of single-mode fiber is 0.8474 nm/m-1, and the intensity sensitivity is 0.0036 a.u./m-1. The resonance valley wave-length sensitivity of the multi-mode fiber SPR curvature sensor is 0.3348 nm/m-1, and the intensity sensitivity is 0.0026 a.u./m-1. The proposed sensor is insensitive to tem-perature and strain, and the working band is controllable, which provides a new, to the best of our knowledge, solu-tion for wavelength division multiplexing multi-channel fiber curvature sensing.

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