Nonlinear encoder, encoding method and optical transmission system

Abstract

A non-linear encoder, an encoding method and an optical transmission system are disclosed. The invention relates to the field of high-speed and long-distance optical transmission networks. The non-linear encoder comprises: a non-negative conversion module, which is used for converting a real part or imaginary part signal of an input M-order QAM signal into a non-negative number x.(n) with a minimum difference value of 1, n being a number of a time sequence and being a non-negative integer; a delay feedback module, which is used for carrying out delay, feedback and summation on the x.(n) to obtain y.(n), and the linear transformation module is used for carrying out linear transformation on the y.(n) to obtain y(n). According to the method, the M-order QAM signal is coded into the 4M-order QAM signal in non-equal probability distribution, so that spectrum compression is realized, and the ISI borne by the signal after spectrum compression is greatly reduced through a bandwidth limited channel, so that the transmission performance can be effectively improved, the transmission performance loss caused by bandwidth limitation is reduced, and the transmission quality is improved.

Description

technical field [0001] The invention relates to the field of high-speed and long-distance optical transmission network, in particular to a nonlinear encoder, an encoding method and an optical transmission system. Background technique [0002] In order to achieve long-distance high-speed optical transmission with a single wavelength rate of 400Gb / s or more, the optical transmission system will use high baud rate signal transmission, which will reach more than 60Gbaud, and the digital-to-analog converter (Digital to analog converter, DAC), driver, The bandwidth of optical I / Q modulators, coherent receivers at the receiving end, analog to digital converters (Analog to digital converter, ADC) and other optoelectronic devices often cannot fully meet the requirements. Compared with the limited bandwidth of the signal baud rate, it will not be possible Avoid introducing intersymbol interference (Inter symbol interference, ISI), thereby affecting signal transmission quality. Conte...

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Problems solved by technology

[0002] In order to achieve long-distance high-speed optical transmission with a single wavelength rate of 400Gb / s or more, the optical transmission system will use high baud rate signal transmission, which will reach more than 60Gbaud, and the digital-to-analog converter (Digital to analog converter, DAC), driver, The bandwidth of optical I / Q modulators, coherent receivers at the receiving end, analog to digital converters (Analog to digital converter, ADC) and other optoelectronic devices often cannot fully meet the requirements. Compared with the limited bandwidth of the signal baud rate, it will not be possible Avoid introducing intersymbol interference (ISI), thus affecting the quality of signal transmission

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