Equivalent circuit model analysis and parameter extraction of DFB semiconductor laser based on rate equations

The output characteristics of distributed feedback (DFB) lasers are greatly affected by different values of the parameters in rate equations. However, there is a lack of simple and feasible parameter extraction methods to determine the values of these parameters. In this paper, a straightforward method for modeling and parameter extraction of the equivalent circuit model for DFB laser based on rate equations is presented which mainly combines those intrinsic parameters into new parameters that can be easily extracted from the external performance of the laser. Before extraction, a laser equivalent circuit model is established based on the transformed rate equation, which can accurately simulate the nonlinear characteristics of DFB lasers. Moreover, based on the output characteristics of semiconductor lasers, the parameters of them are extracted by formula transformation and data fitting. The extracted parameter values are comparable to the reported theoretical and experimental data, validating the accuracy of the extraction method in this paper. Additionally, good agreement is reached between the simulation results and the reference data when the extracted parameter values are used in the model. Meanwhile, it turns out that changes in different physically plausible parameter values have different effects on the external output characteristics. In summary, the method of parameter extraction described in this paper has a good guiding significance for the improvement of laser manufacturing and performance.