Research On Parameter Monitoring Technology In Coherent Detection Of 100G DP-QPSK Optical Signal

At present,the access of massive mobile devices and the development of high-definition video,live broadcast,Internet of Things,VR/AR and other applications promote the continuous development of optical communications.The 100 G DP-QPSK coherent optical communication system has become the mainstream of current optical communication systems benifited from coherent detection technology and DSP technology.The 100 G DP-QPSK coherent detection optical module is the receiver of the coherent optical communication system.It is mainly composed of integrable tunable laser assembly,integrated coherent receiver,high-speed ADC,DSP and master chip,which can realize digital coherent detection.During the operation of the optical module,some parameters need to be monitored to ensure the effect of coherent detection.In this paper,the 100 G DP-QPSK digital coherent detection technology is studied.The influence of DSP temperature,received optical power and chromatic dispersion on coherent detection is analyzed.The monitoring schemes of these three parameters are proposed and experiments are carried out.Finally,the monitoring software of optical module is designed and tested.The main contents of this paper include:(1)Analyze the necessity of DSP temperature monitoring for coherent detection of optical modules.A platinum resistance temperature measurement circuit is designed and a platinum resistance nonlinear compensation algorithm is proposed.Finally,Multisim is used to simulate the temperature measurement circuit,and the experimental data is nonlinearly compensated.(2)Discuss the signifance of the received optical power measurement.An optical power measurement circuit including a logarithmic amplifier circuit is proposed,which is simulated by Multisim and calibrated the noise of the measurement data.(3)Firstly,the basic principle of dispersion is studied.Then the pratical significance of dispersion monitoring is expounded.A two-stage joint dispersion estimation algorithm is proposed on account of the algorithm of estimating dispersion by auto-correlation of signal power waveformand the dispersion search algorithm based on frequency domain cost function.Finally,use Optisystem and MATLAB to jointly simulate and compare the dispersion estimation algorithm.(4)The upper computer software of optical module parameter monitoring is designed and tested by 100 G coherent detection hardware platform.