Effect Of Optical Source Line-width And OSNR On Phase-Estimated Optical Coherent Receiver

Next generation of optical fiber communication system is developing toward higher speed,larger capacity and longer distance. Compared with the conventional intensity modulation/directdetection system, with the aid of new type modulation technology and high-speed digital signalprocessing (DSP) technology, the coherent optical communication technology has become one ofthe most competitive technology in the next generation of high-speed optical fiber communication.Phase noise and additive noise are main influence factors in the coherent optical system, so studyingthe model and its numerical analysis method is particularly important.Firstly, based on a typical coherent optical communication system model, the noise of thedigital signal processing module of the receiver is analyzed. Considering the correlation problem ofthe phase noise and additive noise in coherent optical analogue communication, a multipleuncorrelated gaussian white noise based on parallel processing is proposed. The improvement planadds the parallel processing method in the simulation of phase noise and additive noise. Schemeshave two parallel methods to improve: block-splitting and leap-frog method. Each data streamingcalculates independently, in order to decrease the correlation between the phase analogue noise andadditive analogue noise, the simulation results are more close to the true noise in actual system.Finally, when put these noises in the coherent optical receiver system, the applicable scope ofthe traditional PE and DAML scheme is discussed, the effect of optical source linewidth and SNRon phase-estimated optical coherent receiver is analyzed, too. Simulation results verify thefeasibility of this algorithm. The simulation results show that: when using the new algorithm, boththe carrier phase estimation of Mth power and the carrier phase estimation of DAML can benefitfrom it.，it’s more close to the actual performance of the system.