Evaluation of an automatic method to extract the grating coupling coefficient in different types of fabricated DFB lasers

Distributed feedback (DFB) laser parameters such as grating coupling coefficient, effective indices, facet reflectances, and the phases of facet reflectances have been determined using a method based on least-square fitting of theoretical spectra to measured, subthreshold DFB laser emission spectra. The only inputs needed are geometrical parameters such as length, grating period, and internal grating phase shifts. A larger number of devices have been successfully characterized, and consistent results have been obtained in both 1.3-/spl mu/m multi-quantum-well (MQW) DFB lasers with both facets as-cleaved, and in 1.55-/spl mu/m MQW DFB lasers with no, one, or two facets as-cleaved.