Degradation analysis of 830nm laser diodes based on PSpice model

Researches on the degradation mechanisms of Laser diode (LD) widely used in the fields of laser communication, medicine and military affairs remain to be complex and difficult. Distincting from formal degradation analysis methods of complicated mathematical calculations and verifying experiments, an alternative efficient method is required. In this work, a new circuit model integrating the thermal and degraded effects is obtained, which efficiently reflects the characteristics of LD at actual work and overcomes the insufficiency of classic single component simulation model. The two main degradation modes, the active region defects growth and cavity surface oxidation, are quantitatively described in this new circuit model through improving the expression of non-radiative recombination current In and absorptive rate of cavity surface A;. The model is implemented in the circuit simulator PSpice and verified in the LD characteristic test experiment platform, then the key parameters are identified by the method of nonlinear least square fitting of experiment data. Simulation and experiment results show that, the model can effectively illustrate the degradation characteristics of LD and the parameters, threshold Ith and slope k of I-P curves, can be used to identify the active region and the cavity surface degradation.