Research On Reliability Of High Speed Directly Modulated Semiconductor Laser

At present,with the rapid development of big data and artificial intelligence,the 5th generation mobile communication technology(5G)has officially entered commercial use,as a key component in short-distance optical fiber communications and 5G fronthaul solutions,the market demand for high-speed direct modulation semiconductor lasers has further increased.Therefore,this thessis has carried out the reliability research based on a novel high-speed directly modulated distributed feedback lasers integrated with active Bragg reflector(ADR-DFB laser),and the main research work is as follows:According to the rate equation model,the electro-optical conversion process of semiconductor lasers is theoretically analyzed,and the laser performance parameters commonly used in reliability tests are analyzed.According to the failure model of semiconductor lasers—bathtub curve,the common failure modes and failure mechanisms of semiconductor lasers are introduced and discussed.Based on the wafer-level testing of surface emitting devices,an on-chip automatic test system is built for edge emitting devices such as ADR-DFB lasers,and the test program is mainly written in Python.The test system can test nearly 18,000 lasers on a 2-inch wafer in3 hours.Wafer-level testing and screening can greatly reduce the manufacturing cost of the device.The constant stress accelerated life test for ADR-DFB lasers has been designed and implemented according to the accelerated life test theory and the general reliability standard GR468 for communication devices.Three sets of accelerated stresses of 85℃ 85mA,85℃100mA and 100℃ 100mA are mainly selected for high-temperature and high-current timed tail-cutting accelerated tests.According to the Weibull distribution,which is commonly used in the life distribution of semiconductor lasers,the accelerated life test data is processed and analyzed.After fitting and calculating the data,it is obtained that the activation energy for failure of ADR-DFB lasers is 0.45 e V,and that the parameter value of the current acceleration model is 2.09.Then through the definition of the average life and acceleration factor in the reliability theory,it is calculated that the life of ADR-DFB laser can reach the requirements of communication applications for more than 20 years under normal working conditions(50℃ 50mA),which verifies the high reliability of ADR-DFB lasers.Finally,the failure analysis was carried out on the failed devices,and the failure reasons were discusssed.