OPTICAL FIBER SENSORS BASED ON LONG-PERIOD GRATINGS IN PHOTONIC CRYSTAL FIBERS
Chun-Liu Zhao
Abstract:
In this paper, we investigate in detail the characteristics of a LPG written in an endlessly-single-mode (ESM) solid silica core PCF both theoretically and experimentally. By use of a dispersion factor, a deeper understanding of the behavior of LPG in the ESM-PCF is achieved. Our analysis clearly reveals the significant effect of the waveguide dispersive characteristics of the cladding modes on the strain and temperature characteristics of the LPG in the ESM-PCF. By selecting an appropriate grating period, a LPG with approximately zero temperature sensitivity but large strain sensitivity is realized. By utilizing the properties of LPGs in the PCF, we realize a simple temperature-insensitive strain sensor, a stable demodulator of a fiber Bragg grating temperature sensor, and others.
