Multichannel parallel photoelectric detection circuit structure

Abstract

The invention relates to the technical field of optical communication, in particular to a multichannel parallel photoelectric detection circuit structure which comprises a detector, a first-stage amplification unit, a second-stage amplification unit, a filtering unit and a multichannel synchronous ADC which are connected in sequence. The detector converts the optical signal into a current signal;the first-stage amplification unit is composed of a transimpedance amplifier and amplifies the current signal into a voltage signal; the second-stage amplification unit is composed of n operational amplifiers with different amplification factors, and is connected behind the trans-impedance amplifier in parallel to form parallel n channels; the filtering unit consists of n low-pass filters with different bandwidths and is connected behind the n operational amplifiers in parallel; and the multi-channel synchronous ADC is connected behind the n low-pass filters, and synchronously acquires data under n magnification times. The circuit adopts a multi-channel parallel structure, can collect multi-gear gain signals at the same time, improves the detection efficiency, effectively reduces the noise, improves the signal-to-noise ratio, and improves the dynamic range of detection.

Description

【Technical field】 [0001] The invention relates to the technical field of optical communication, in particular to a multi-channel parallel photoelectric detection circuit structure. 【Background technique】 [0002] With the rapid development of optical communication technology, it is common to monitor the optical signal strength in the optical network system link to monitor the performance degradation or failure of the optical fiber optical path in the optical network system, thereby improving the stability and reliability of the optical network system. sex. A typical photoelectric detection circuit structure used in optical network system monitoring is as follows: figure 1 As shown, it includes a detector, a transimpedance amplifier, a low-pass filter, an analog-to-digital converter (Analog to Digital Converter, abbreviated as ADC) and a processor. Among them, the detector mainly converts the optical signal into an electrical signal; the transimpedance amplifier mainly ampl...

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Problems solved by technology

[0003] However, the above-mentioned photodetection circuit structure usually has the following disadvantages: when the detection circuit gain is small, for an optical signal with a low input optical power, the converted voltage signal may be lower than the minimum input voltage of the ADC, so that the signal is submerged in the noise However, when the gain of the detection circuit is large, the converted voltage signal may be higher than the maximum input voltage of the ADC for an optical signal with a high input optical power, causing the signal to appear saturated and distorted. Perform effective analysis and monitoring

[0005] However, the above method can only be in one gain gear at the same time. In fact, it is based on the serial method of time division multiplexing, that is, only one of the three switches SW1, SW2, and SW3 can be closed; for applications with large changes in input optical power In the scene, it is necessary to switch the gain gear frequently, that is, to switch back and forth between the three switches, resulting in low detection efficiency

At the same time, due to the serial mode, the low-pass filter before entering the ADC must meet the bandwidth corresponding to the minimum gear gain, and the bandwidth is a single fixed larger value, and since the noise is the integral of the bandwidth, the larger the bandwidth, the greater the noise The larger the , the lower the signal-to-noise ratio, affecting the dynamic range of photodetection

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