Control Technology For DBR Laser And Application In PON-ONU

Tunable semiconductor lasers have significant applications in the next generation passive optical networks.With their fast wavelength switching ability and wide wavelength tuning range,extensive attention have been paid from researchers.The distributed bragg reflector(DBR)laser plays an important role in the optical network unit(ONU)of the passive optical network(PON).In addition,dual-mode tunable lasers show potential applications in all optical signal processing and microwave photon generation.In this thesis,it starts from the wavelength tuning principle of the DBR lasers,and studies single mode tuning characteristics,small signal response and dual-mode lasing of the DBR lasers.Focusing on the application of DBR laser in PON-ONU,a high-speed transceiver card based on field programmable gate array(FPGA)is designed and related experiments are carried out.The specific contents are as follows:(1)Starting from the working principle of semiconductor laser,the structure and wavelength tuning principle of DBR laser are introduced,including the active region,grating section and phase section of DBR laser are discussed.The threshold condition and longitudinal mode characteristic of DBR laser are analyzed.(2)The wavelength tuning characteristics of the DBR laser are studied.The static tuning curve of output wavelength,side mode suppression ratio and optical power of DBR laser are experimentally measured.Based on the above test results,a dual-mode lasing current compensation scheme for a DBR laser is proposed.The stability and continuous tuning of the DBR laser under the current compensation are verified by experiments,and the stability is analyzed.(3)According to the above research,the DBR laser is used as the light source of the tunable transceiver in PON,and the high-speed transceiver board based on FPGA is designed.The DBR laser and receiver optical subassembly(ROSA)are designed on a single board independently.It greatly facilitates the device replacement,system upgrading and debugging.The startup,download and peripheral control circuit of the FPGA system are designed on the motherboard.A high-speed transceiver card is fabricated,the wavelength tuning and related experiments at 2.5 Gbps and 5 Gbps are performed.