Our technique exploits the reflection characteristics of fiber Bragg gratings written in polarization-maintaining fibers to create a frequency discriminator, which is able to convert PM/FM signals into intensity-modulated (IM) signals. We propose a simple analysis of a single-multimode-single-mode fiber (SMSMF) filter by observing the excited modes in multimode fiber (MMF). In this paper, a novel demodulation algorithm based on the variable-step-size method and cross-correlation algorithm is proposed to demodulate the wavelength of an FBG. By changing the step size of each calculation. The invention provides an array single-mode device and a fiber grating demodulator, which comprises a packaging box, input single fibers, a first optical branching chip and a second optical branching chip, wherein the second optical branching chip and the first optical branching chip are both. The XH-FBG fiber grating temperature sensing product is a sensing detection system developed based on (Bragg) grating technology. It can measure the temperature of the measured part. It has high temperature measurement accuracy, short response time, anti-electromagnetic interference, electrical. FMCW lidar offers higher sensitivity and virtually interference-free operation when compared to conventional time-of-flight lidar.
