Research On The Degradation Mechanism And Build-in Test Of Laser Diodes

Laser diode(LD)is widely used in defense and economic fields,which is one of the most universal type of lasers so far.Due to the high degree of sophistication and integration of LD,it is difficult to directly observe the damage site when degradation occurs.Therefore,how to characterize and test the degradation of LD without affecting the normal operation of LD is an urgent problem to be solved in the research of degradation mechanism and build-in test(BIT).In order to solve the problem of degradation mechanism and BIT of LD,a degradation model was established to analyze the degradation and design the BIT.Finally,the feasibility and validity of the model and BIT are verified in experiments.The main contents of this thesis include:1.Analysis and modeling of degradation mechanism of LDIn order to analyze the degradation process and influence factors of LD,two typical degradation modes,active region degeneration and cavity surface degeneration,are deeply analyzed from the physical structure level to establish the theory and circuit equivalent model and to describe the degradation degree.In order to study the degradation characteristics of LD,a method based on the intrinsic model of LD is proposed to combine the degradation characteristic model with the thermal characteristic model.2.Parameter selection and test of degradation characterization of LDIn order to solve the problem that the degraded parts of LD can not be directly observed,PSpice is used to simulate the degradation model,and the characteristic parameters of LD after degradation are analyzed.Based on the characterization and sensitivity of each characteristic parameter,the threshold current and slope efficiency are selected as the characterization parameters of degradation,and the test method is studied.3.BIT for degradation monitoring of LDIn order to overcome the shortcomings of the off-line test of degradation characterization parameters and the traditional monitoring protocols,a BIT method is proposed to increase modulating current as monitoring parameters to characterize degradation.Then,the BIT hardware and software based on ARM are designed in detail.4.Verification and modification of LD modelBased on the coaxial double-heterojunction LD,the computer control analysis module and the data transmission module are added to form the characteristic parameter testing platform on the basis of the BIT method.By testing the characteristic parameters of LD,the key parameters of the model are identified and the models and methods are modified.Experimental results show that the simulation model used to study the degradation mechanism of LD and to guide the design of BIT is valid and feasible.