光纤振动传感器的信号检测电路设计

基于干涉仪的相位调制型光纤传感器具有极高的灵敏度,其中探测微弱光信号的光电信号检测电路起着重要的作用。针对光纤振动传感器系统,分析了PIN光电二极管前放电路和典型跨阻抗PIN-FET的组件电路,为减小前放I/V变换电路中跨阻阻值很大而带来的热噪声,设计了T型电阻网络。利用结构简单、性价比高的PIN光电二极管的前放检测和滤波器电路,对Sagnac干涉仪的输出的光信号进行了检测。实验表明该电路有效地降低了输出光电流噪声的均方值,其性能可靠,完全满足振动传感器的实际应用的测量要求。

Design of test circuit for fiber optic perturbation sensor

The phase modulation fiber optic sensor based on interferometer is provided with high detective sensitivity,and the testing circuit is playing an important role in receiving and detecting weak optic signals.For the fiber optic perturbation sensing system,both the preamplifier of PIN photodiode and the combination circuit of PIN-FET were analyzed.A T-type network of resistor was designed to replace the large transimpedance of current to voltage(I/V)transducer to reduce the thermal noise.A testing circuit with simple structure and high-ratio of performance to price was presented,which included the preamplifier of PIN photodiode and the filter,and was used for detecting optic signals outputting from the Sagnac interferometer.Experiment was performed in measuring the photoelectric signals.The result indicates that the circuit is available in depressing the root mean square of the optic current output noise;it can meet the demand of perturbation sensor with the stabile performance.