Phase demodulator, optical fiber sound pressure demodulation system, demodulation method and manufacturing method

Abstract

The invention, which is suitable for the technical field of the sound pressure measurement device, provides a phase demodulator, an optical fiber sound pressure demodulation system, a demodulation method and a manufacturing method. The phase demodulator employing a Sagnac fiber loop structure comprises a broadband light source, a photoelectric detector, a signal analysis module connected with the photoelectric detector, a first optical fiber coupler connected with the broadband light source and the photoelectric detector, a tunable optical attenuator, a fiber delay line connected with the first optical fiber coupler, a second optical fiber coupler, an optical frequency shifter, and a fiber depolarization device. The tunable optical attenuator connected with the first optical fiber coupler is used for adjusting the intensity of CW light or adjusting the intensity of CCW light; the second optical fiber coupler connected with the fiber delay line and the tunable optical attenuator is used for realizing coupling of light reflected by a membrane type optical fiber sound pressure sensor; the optical frequency shifter connected with the second optical fiber coupler provides stable pi/2 quadrature phase biasing; and the fiber depolarization device connected with the optical frequency shifter is connected with the membrane type optical fiber sound pressure sensor externally by a fiber. According to the invention, stable phase demodulation of the membrane type optical fiber sound pressure sensor is realized. 本发明适用于声压测量装置技术领域，提供了一种相位解调器、光纤声压解调系统、解调方法及制造方法，该相位解调器，采用Sagnac光纤环的结构，包括宽带光源，光电探测器，连接光电探测器的信号分析模块，还包括：分别连接宽带光源以及光电探测器的第一光纤耦合器；连接第一光纤耦合器，调节CW光的强度，或者调节CCW光的强度的可调谐光衰减器；连接第一光纤耦合器的光纤延时线；分别连接光纤延时线以及可调谐光衰减器，耦合膜片式光纤声压传感器反射的光的第二光纤耦合器；连接第二光纤耦合器，提供稳定的π/2正交相位偏置的光移频器；连接光移频器，且通过光纤外接膜片式光纤声压传感器的光纤去偏振器。本发明实现了膜片式光纤声压传感器的稳定相位解调。