Power equalization method and apparatus for passive optical network, terminal, unit and system

Abstract

The invention provides a power equalization method and apparatus for passive optical network, a terminal, a unit and a system, and relates to the field of communication. The method is applied to an optical line terminal OLT and comprises the following steps: detecting the power of an optical network unit ONU; and comparing the detected power of the ONU with a preset threshold, when the power is greater than or equal to the preset threshold, releasing a working waveband adjustment instruction to the ONU, so that the ONU changes the working waveband into a waveband with power smaller than the preset threshold in the ONU. The scheme provided by the invention solves the problems of poor adaptability and high cost of the existing method, and can realize the power equalization of a time division wavelength division multiplexing passive optical network TWDM PON system.

Description

technical field [0001] The present invention relates to the communication field, in particular to a method, device, terminal, unit and system for power equalization of a passive optical network. Background technique [0002] With the development of network technology, the network can be used to transmit a large number of services such as voice, data, and video, so the requirements for bandwidth continue to increase. Passive Optical Network (PON) was born under this demand. The PON system usually consists of an optical line terminal (Optical Line Terminal, OLT for short), an optical network unit (Optical Network Unit, ONU for short) on the user side, and an optical distribution network (ODN). Point-to-multipoint network structure. ODN consists of single-mode optical fiber, optical splitter, optical connector and other passive optical components, and provides optical transmission medium for the physical connection between OLT and ONU. In order to further improve the bandwidt...

AI Technical Summary

Problems solved by technology

[0007] (1) TWDM PON is a multi-wavelength wavelength division multiplexing system. The DFB (Distributed Feedback, distributed feedback) laser used works in one channel. Although the side mode suppression ratio is high, it will still be in the adjacent channel. There is a certain optical power output. If the interfered channel happens to be 20dB lower than the channel power, this will seriously deteriorate the signal quality of the interfered channel. This is the unique OOB / OOC (OUT OF BAND / OUT OF CHANNEL, Out-of-band data) problem, in order to make the system work normally, the side mode suppression ratio of the laser is very high, which poses a serious challenge to the existing laser technology;

[0008] (2) The sensitivity of the current transmitter does not reach the -36.5dBm defined by the TWDM PON standard. Generally, an amplifier needs to be added to the TWDM PON network, and the stability of the gain control of the amplifier is also about 1dB. Therefore, in a single channel, the OLT The maximum difference in receiver power can reach 21dB

This has very high requirements on the receiver. The dynamic range of the TIA in the receiver must reach 21dB, which is very difficult to implement and the cost is also high.

[0009] (3) The gain flatness of the optical amplifier is about 1dB. Therefore, when the optical signals of different wavelengths reach the wavelength division multiplexer (WM), the difference in optical signal power can reach as much as 21dB. In the worst case, it takes So that the crosstalk between channels will not interfere with the signal, the isolation requirement of the wavelength division multiplexer is also very high, and the cost is greatly increased

[0010] It can be seen that the root of the above problems lies in the serious power imbalance in the TWDM PON system

However, the traditional method of solving power balance is not suitable for TWDM PON systems. At the transmission node, fast SOA (semiconductor optical amplifier, semiconductor optical amplifier) ​​is used to adjust the gain of different burst packets to solve the power balance of passive optical network. Problems, however, become completely inapplicable or costly due to the multi-wavelength multiplexing and bursty network architecture of TWDM PON

Another dynamic adjustment method requires the ONU to have an adjustable output power function, so that the output power of each ONU can be measured and adjusted at the local end through management designation. The existing technology can only allow the output power of the transmitter to be adjusted in a small range ( Such as + / -3dB), to support a wider range of adjustment, the ONU optical module needs to add a variable optical attenuator (VOA) or optical amplifier (SOA), which increases the complexity of the optical module and brings a significant increase in cost , so the defect is very obvious

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