Title :
Effect of residual facet reflectivity on the front-rear correlation and nonlinearity of L-I characteristics in quarter-wavelength-shifted DFB lasers
Author :
Kim, Sang-Bae ; Cho, Jong-Sup
Author_Institution :
Dept. of Electr. & Electron. Eng., Ajou Univ., Suwon, South Korea
Abstract :
Combined effects of residual facet reflection and spatial hole-burning on the front-rear correlation and nonlinearity in L-I characteristics of quarter-wavelength-shifted DFB lasers have been studied by using an effective index transfer matrix method and rate equations. Changes in front-to-rear power ratio, caused by the spatial hole-burning and asymmetric facet-reflection due to the different grating end phases at the two facets, are shown to be responsible for both the correlation and the linearity problems, while the threshold gain change causes the linearity problem only. The problems are serious even in the cases of low facet reflectivity of 0.3%.
Keywords :
diffraction gratings; distributed feedback lasers; laser theory; optical correlation; optical hole burning; optical transmitters; reflectivity; refractive index; semiconductor device models; semiconductor lasers; L-I characteristics; asymmetric facet-reflection; effective index transfer matrix method; front-rear correlation; front-to-rear power ratio; grating end phases; linearity problem; linearity problems; low facet reflectivity; nonlinearity; quarter-wavelength-shifted DFB lasers; rate equations; residual facet reflectivity; semiconductor lasers; spatial hole-burning; threshold gain change; Distributed feedback devices; Fiber lasers; Gratings; Laser feedback; Laser modes; Laser theory; Linearity; Power generation; Reflectivity; Semiconductor lasers;
Journal_Title :
Photonics Technology Letters, IEEE
