A circuit that detects the average optical power at the pina end

Abstract

The invention provides a circuit for detecting average optical power at the PINA end, comprising: a transimpedance front-end amplifier circuit and a negative feedback network whose input end is a gate; Current I PD converted to a voltage signal V OUT output, and a voltage signal V is generated at the PINK terminal PINA ; The negative feedback network includes the first operational amplifier I0 and the second operational amplifier I1; the voltage signal V OUT Input the negative input terminal of the second operational amplifier I1; the voltage signal V PINA Input the positive input terminal of the first operational amplifier I0; the first resistor R is connected between the negative input terminal of the first operational amplifier I0 and the positive input terminal of the second operational amplifier I1 f ', its resistance and transresistance R f same. The invention provides a circuit for detecting average optical power at the PINA end, which has low power consumption and high detection precision.

Description

technical field [0001] The invention relates to the field of optical communication, in particular to a circuit for detecting average optical power. Background technique [0002] In modern optical fiber communication applications, real-time monitoring of optical pulse power transmitted by optical fibers is required to realize intelligent diagnosis of communication faults. To realize the monitoring of the received optical power, the photocurrent of the photodiode can be monitored, and then the optical power can be deduced and converted backwards. In this field, monitoring the photocurrent of the photodiode in the receiving component has the following difficulties: [0003] First, the monitoring photocurrent is small: accurate monitoring of the received optical power usually requires a circuit with high sensitivity. Taking the 1.25Gbps application as an example, such a transmission rate needs to monitor the optical power below -30dBm, which is converted into a photocurrent of...

AI Technical Summary

Problems solved by technology

[0005] Furthermore, the problem of monitoring loss: the rear stage of the photodiode needs to be connected to a TIA (transimpedance amplifier). Since the TIA is a high-speed, low-noise circuit, the photocurrent monitoring device introduced cannot affect the bandwidth and low-noise characteristics of the TIA. Good enough isolation state, which is also one of the difficulties in monitoring circuit design

The input terminal of the operational amplifier is directly connected to the input terminal of the TIA, which will form a capacitive load, thereby increasing the equivalent input noise of the TIA signal channel, and reducing the bandwidth, thereby degrading the sensitivity

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