Research on fiber grating sensing to fiber loop ringdown

A fiber loop consists of two couplers and a single mode fiber and the measured pressure is converted into ringdown time of light traveling in the fiber loop by the sensor element of FBG. When pressure is changed, the pressure will be directly proportional to the ringdown time which is identical to that of theory. This kind of system of measuring press based on the theory has advantages of simple composition and convenient measure and it provides a novel method of fiber gratting demodulation technology and has practical value. Apart from measuring press, it can measure temperature and other parameters.