Circuit for measuring outburst mode optical signal power

Abstract

The invention discloses a burst mode optical signal power measuring circuit which comprises a photoelectric detector power supply, a mirror image current source and a subsequent circuit. The subsequent circuit is divided into a signal passage part and an optical power burst detecting part by the mirror image current source, wherein, in the signal passage part, optical current generates a burst detection signal by the photoelectric detector via a trans-impedence amplifier and a burst detection circuit, and the burst detection signal is used for triggering a time sequence generation circuit to generate a control time sequence for maintaining sampling and carrying out digital-to-analog conversion; in the optical power burst detection part, an amplifying circuit converts the mirror image current into a voltage signal; therefore, a sampling maintaining circuit and a digital-to-analog conversion circuit which are connected with the time sequence generation circuit can finish the burst detection of optical power under the control of the control time sequence. The burst mode optical signal power measuring circuit generates the mirror image current forming a proportion with the average optical current of the photoelectric detector by the mirror image current source, realizes the detection to the burst mode optical power under the control of the control time sequence, and can measure burst optical signal power with the length of hundreds of nanoseconds.

Description

technical field [0001] The invention relates to a circuit for measuring optical input power in the technical field of optical communication, and relates to a power measurement circuit of a burst mode optical signal of a point-to-multipoint optical network such as a passive optical network. technical background [0002] The construction of access network based on passive optical network technology is a bright spot in the optical communication industry in recent years. Passive optical network is a point-to-multipoint system, an optical line terminal (OLT) and multiple optical network terminals (ONT) Through the tree-shaped optical fiber link connection, not only part of the optical fiber link resources are shared, but also the cost of the optical line terminal (OLT) is shared, and the cost of the optical line terminal (OLT) does not require active devices in the middle, which greatly reduces the cost of network construction. and maintenance costs. [0003] In the passive opti...

AI Technical Summary

Problems solved by technology

[0004] In the existing technology, some methods of converting the photocurrent of the photodetector into a voltage signal and then using a comparator to set the threshold to generate a trigger condition for burst optical power input are used to perform burst sampling, but in order to ensure at least The dynamic range of the input optical signal power is above 30dB. When the full scale of the analog-to-digital conversion is 2.5V, when the system is near the sensitivity, the voltage value corresponding to the optical power is only 2.5mV. At this time, the threshold level set by the comparator has already entered noise threshold, making it difficult for the system to work stably

At the same time, the discharge circuit with single-stage gain is also difficult to meet the measurement requirements of a wide range

There is also a technical scheme of using a current-voltage type logarithmic amplifier for burst sampling, but due to the long response time of the current-voltage type logarithmic amplifier (several microseconds to hundreds of microseconds), even with a dummy load The method is also difficult to reach hundreds of nanoseconds, and it is difficult to meet the actual test requirements. Therefore, it is still difficult to effectively solve the power measurement of burst optical signals in the current technical solutions.

Images