Estimating the parameters of semiconductor lasers based on weak optical feedback interferometry

The paper presents a new approach for measuring the linewidth enhancement factor (LEF) of semiconductor lasers (SL) and the optical feedback level factor C in SLs. The proposed approach is based on the analysis of self-mixing signals observed in self-mixing optical feedback interferometry. Unlike existing approaches, the approach tries to estimate the parameters LEF and C by a gradient-based optimization algorithm that achieves best data-to-theoretical model fitting. The effectiveness and accuracy of the method have been confirmed and tested by theoretical analysis and computer simulations.