Optimization Design Of Integrated Optical Network Unit For NGPON

The requirements of large capacity,spectrum utilization and low cost have brought great challenges to the design of the access network.On the one hand,the design of the optical access network needs to increase the transmission capacity while increasing the number of users.On the other hand,optical network units(ONUs)require the use of low-cost,largescale integrated devices.Ultra-dense wavelength division multiplexing technology has the advantages of small channel spacing and high sensitivity due to the use of coherent detection.Under the same signal transmission bit rate,it can improve the mobile fronthaul air interface rate and become a research hotspot.Semiconductor Optical Amplifier(SOA)and Electroabsorption Modulated Laser(DFB-EAM),as integrated passive nonlinear devices,have the advantages of high modulation rate,stable performance,small size,and low cost,which providing a feasible scheme for the large-scale deployment of ONUs.The main tasks are as follows:1.The structure and working principle of SOA and DFB-EAM are expounded.First,based on the SOA broadband theoretical model,a uniform buried ridge model of In PIn Ga As P is established.Then,SOA and DFB-EAM carried out characteristic analysis and obtained the optimal working range of input optical power,bias current and bias voltage selected when carrying signals,which providing certain data support for the parameter selection of ONU integrated devices.2.Based on the establishment of the SOA dynamic model,a full-duplex DWDM-PON system based on a single-chip integrated DFB-EAM-SOA under 10 Gb/s is established,and the receiving sensitivities at the standard forward error correction(FEC)level are obtained.Compared with the traditional laser,the adopted integrated DFB-EAM-SOA has wider modulation bandwidth and lower chirp parameter,which not only further increases the noise tolerance of the system and improves the signal quality in the optical access network,but also strongly proves that the advantages of integrated passive nonlinear devices in the deployment of access network systems are presented.3.The superiority of coherent detection compared to direct detection is further verified by simulation experiment,and a full-duplex UDWDM-PON system based on single-chip DFB-EAM is built.By analyzing the bit error rate and eye diagram quality of optical transmission signal,the transmission performance and signal quality of the UDWDM-PON system are higher than that of the DWDM-PON system,and it is one of the most attractive candidates for the research of the next-generation optical access network.This paper focuses on the optimization design of the integrated optical network unit for NGPON.Starting from the characteristics of the key components SOA and DFB-EAM,a lowcost,integrated optical network unit is constructed,and the transmission models of DWDMPON and UDWDM-PON full-duplex access networks are established.The modulation efficiency of the devices,the bit error rate and receiving sensitivity of the system are all analyzed in detail,which provides a certain theoretical basis for the large-scale deployment and promotion of the integrated ONU.