干涉法interferometry原理：利用光纤受到所检测物理场感应，如，温度、压力或振动等，使相位产生延迟，经由相位的改变，造成输出光的强度改变，进而得知待测物理场的变化。Principle: the optical fiber is induced by the detected physical field, such as temperature, pressure or vibration, so that the phase of the guiding light will be delayed. Through the phase change, the intensity of the output light will be changed, and then the change of the physical field to be measured will be known.