小型化四通道光纤法珀传感器解调系统设计

Design of miniaturized four channel fiber Fabry-Perot sensor demodulation system

针对目前多通道光纤法珀压力传感器解调系统体积大、功耗高的不足,提出一种通过MEMS光开关快速连续切换实现四通道解调的方法,选用了一款低功耗CMOS图像传感器S11639并搭建了以FPGA为核心的硬件解调电路,通过编写S11639及AD9826驱动程序完成多通道切换逻辑约束以及干涉光谱的采集,最后经过数据处理和传输部分将各通道所接传感器的腔长在上位机中实时显示。利用标准解调仪器确定标定系数并对4个通达所连接的压力传感器进行腔长的实际测量,腔长测量过程中均无跳点,说明设计的四通道解调系统标稳定性较好,误差较小。根据测量数据计算出每个通道的非线性度,4个通道中最大的非线性度为0.93%,同时每个通道的解调速度也能够达到10 Hz。

Considering the shortcomings of large volume and high power consumption of the current multi-channel fiber Fabry-Perot pressure sensor demodulation system,proposes a method to realize four channel demodulation through rapid and continuous switching of MEMS optical switch,selects a low-power CMOS image sensor s11639,and constructs a hardware demodulation circuit with FPGA as the core,The multi-channel switching logic constraints and the acquisition of interference spectrum are completed by writing S11639 and AD9826 drivers.Finally,the cavity length of the sensor connected to each channel is displayed in real time in the host computer through data processing and transmission.The calibration coefficient is determined by the standard demodulation instrument,and the cavity length of the four pressure sensors connected to the access is actually measured.There is no jumping point in the process of cavity length measurement,which shows that the four channel demodulation system designed has good calibration stability and small error.The nonlinearity of each channel is calculated according to the measured data.The maximum nonlinearity of the four channels is 0.93%,and the demodulation speed of each channel can also reach 10 Hz.