Adaptive digital signal processing algorithm for compensating optical fiber transmission nonlinear damages

Abstract

The invention discloses an adaptive digital signal processing algorithm for compensating optical fiber transmission nonlinear damages, and relates to the field of optical fiber transmission. The algorithm comprises following steps of setting three nonlinear coefficients after a receiving end receives signals; respectively substituting into an adaptive digital backward propagation algorithm for processing, thus obtaining three signal amplitude values as initial values; estimating the nonlinear coefficients by utilizing the strength variances of the signals, wherein after many times of iteration, an optimum nonlinear coefficient gamma <opt > for nonlinear compensation can be estimated; taking the optimum nonlinear coefficient gamma <opt > as the input of adaptive digital backward propagation; then stopping iteration; carrying out CR (carrier recovery) and decode processing to the signals, thus recovering the signals of a transmitting end; and calculating a BER (bit error ratio). The algorithm provided by the invention can be applied in coherent light communication system of an M-QAM (M-ary quadrature amplitude modulation) high order modulation format; the optimum nonlinear coefficient can be determined more precisely; and the algorithm complexity is reduced.

Description

technical field [0001] The invention relates to the field of optical fiber communication, in particular to an adaptive digital signal processing algorithm for compensating nonlinear damage of optical fiber transmission. Background technique [0002] With the rapid growth of bandwidth demand and the rapid development of optical fiber communication technology, the transmission capacity of optical fiber communication system is approaching the Shannon limit, and one of the main factors limiting the transmission capacity of optical fiber is the nonlinear effect of optical fiber. It is considered a good way to use powerful DSP (digital signal processing, digital signal processing) at the receiving end to compensate the damage caused by nonlinear effects. Among them, the DBP (digital backward propagation, digital back propagation) technology has received great attention due to its advantages of being able to compensate both linear and nonlinear damages of optical fibers. However, ...

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Problems solved by technology

[0004] However, in the existing A-DBP based on signal strength variance, the signal strength variance is directly calculated

Although this method can calculate the fiber nonlinear coefficient of QPSK (quadraturephase shift keying, quadrature phase shift keying) system well, but for M-QAM (M-aryquadratureamplitudemodulation, multi-ary quadrature amplitude modulation format), the result obtained by this method Not optimal, because its algorithm is complex and the effect is not obvious

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