Research of digital compensation for optical signal Chromatic Dispersion in long-haul electric-power communication networks

In 2013, State Grid Corporation of China (SGCC) successfully implemented high capacity backbone Optical Transmission Network (OTN) for cross-province long-haul electric-power fiber communication networks, which achieved comprehensive upgrading of bandwidth capacity and carrier capability. In order to ensure low Bit Error Rate (BER) of transmission signal, OTN commonly utilizes Dispersion Compensation Module (DCM) technique to compensate optical signal distortion induced by Chromatic Dispersion (CD) in long-haul transmission. However, DCM is restricted to pre-define the value of CD during networks construction procedure referring to the employed fiber length in the optical transmission networks. Therefore, DCM is unable to process real-time adaptive optical signal transmission CD compensation. Nowadays, with the rapid developing of advanced applications for smart grid, electric-power communication networks are increasingly demanded to support not only the basic power- electric grid monitoring and controlling signal transmission but also the large capacity, high bit rate, and intensive real-time information flow transmission. In order to fulfill such severe requirements, real-time adaptive optical signal transmission CD compensation technique is strongly recommended to comply. To realize the real-time CD compensation for received signal after optic-digital conversion, we have theoretically proved the digital compensation technique for optical transmission CD based on finite impulse response (FIR) filters using minimum mean square error (MMSE) algorithm. The proposed technique is capable to avoid transmission BER performance worse induced by pre-definition the value of CD. Meanwhile, the proposed technique is able to take advantages of blind estimation property for MMSE algorithm combined with adaptive property for FIR filter to utilize high bit rate, long-haul optical signal transmission CD on-line adaptive compensation. Moreover, in this paper, Matlab simulation res- lts shown the BER performance of long-haul transmission (1000 km) signal using digital CD compensation is approaching the BER performance of back-to-back transmission. Difference between BER vs. optical-signal-to-noise ratio (OSNR) performance is less than 0.5 dB.