Research On Key Techniques Of 100G Coherent Optical Detection

With the increasing popularity of new multimedia technologies such as high-definition television,Internet video and IPTV,the demand for network traffic and network bandwidth is increasing and 100 G DP-QPSK coherent optical communication systems are being commercialized on a large scale.In order to make 100 G DP-QPSK coherent optical detection can be better applied to the optical communication system and to a greater extent increase the network communication capacity,in this paper,the principle of 100 G DP-QPSK coherent detection is studied,and the key parts and critical factors that will impact performance of the coherent optical reception are analyzed in detail.The high-precision clock technology and high-speed calibration algorithm are researched.Finally,all above were simulated and tested on the hardware platform.Specifc work in this paper includes:(1)The basic principle of optical signal coherent detection is studied,and the importance of high-precision clock technology and ultra high speed ADC technology for 100 G DP-QPSK coherent optical detection is demonstrated.High precision clock technology and ultra high speed ADC technology are researched,preparing for the design of the clock scheme and the study of the ultra-high-speed ADC calibration algorithm.(2)Based on the analysis of the clock requirements of 100 G DP-QPSK optical signal coherent detection platform,the simulation and test results of three high-precision clock schemes are analyzed and compared for reference clock of ultra-high speed ADC.It is determined that the clock scheme based on adaptive closed-loop control has the characteristics of high precision and simple implementation.This scheme solves the problem of the reference clock of very ultra-high speed ADC.(3)The mathematic models of the three mismatched effects(offset mismatch,gain mismatch,time mismatch)of time-interleaved ADC are analyzed,and the origin and characteristics of these three mismatched effects are analyzed.The principle of calibration for of each mismatch effects is researched,and calibration algorithm of 64 G ADC is proposed for this subject.Finally,the actual calibration test are performed,which achieved the desired results.(4)Based on the hardware platform of 100 G DP-QPSK optical signal coherent detection,the control software of the hardware platform is designed and implemented.The hardware and software functions and performance of the platform were tested by using test solutions such as near-end loopback,far-end loopback and optical signal access.The results show that the hardware and software functions and performance of the 100 G DP-QPSK optical signal coherent detection platform meet the requirements.