Differential photoelectric detection device and photoelectric test system

Abstract

The invention discloses a differential photoelectric detection device and a photoelectric test system. The device comprises a differential module and an amplification module which are connected with each other, wherein the differential module is connected with two paths of optical signals for differential operation, and outputs photocurrent signals; the amplification module is connected with the photocurrent signals output by the differential module, converts the photocurrent signals into voltage signals and amplifies the voltage signals for output. The device further comprises an output filtering module arranged at the output end of the amplification module, wherein the output filtering module filters out high-frequency noise signals in the output signals of the amplification module, or filters out high-frequency noise signals and resonance signals in the output signals of the amplification module, and outputs a final detection signal; and the system comprises an acousto-optic generating device, the differential photoelectric detection device and a demodulation module. The differential photoelectric detection device and the photoelectric test system have the advantages of simple structure, low cost, high bandwidth, low noise, no resonance, high stability and the like.

Description

technical field [0001] The invention relates to the technical field of photoelectric detection, in particular to a differential photoelectric detection device and a photoelectric test system. Background technique [0002] In laser testing and other technologies, it is often necessary to modulate the laser, such as the test of the Farad rotation angle, Bell-Bloom optical magnetic resonance test, etc. During the test, in order to obtain the photocurrent signal required for the test, it is necessary to perform differential processing on the same laser beam for photodetection. At present, photodetectors usually first differentiate the same laser beam, and then convert it into a voltage signal by the amplifier circuit and amplify it. If the feedback resistor value in the amplifier circuit is set to a small value, the bandwidth of the entire photodetector is small. In the test process, the modulation frequency is usually required to be high, such as the optical magnetic resonance...

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Problems solved by technology

[0004] 1) The output signal of the system is unstable, which will generate a resonance signal and affect the output of the effective signal;

[0005] 2) Due to the large value of the feedback resistor, increasing the amplification factor of the amplifier will also amplify the noise signal, which greatly affects the quality of the system output signal

However, the photoelectric differential detector directly uses a transimpedance amplification circuit, and a resistor is set at the front end of the amplifier, so the transimpedance resistance value must be set to a small value when used, which can only be used in the application of low frequency signals, and for high frequency signals , the combination of the resistor and the photodiode at the front end of the amplifier will oscillate, which will affect the stability of the system signal, that is, it cannot be applied to the application of high-frequency laser signals, and the bandwidth of the entire detector is very narrow

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