Title :
Above-threshold analysis of loss-coupled DFB lasers: threshold current and power efficiency
Author_Institution :
Dept. of Electron. Eng., Chinese Univ. of Hong Kong, Shatin, Hong Kong
Abstract :
The threshold current and power efficiency of loss-coupled DFB lasers have been calculated numerically using an above-threshold model. Compared with perfectly AR-coated devices, lasers with asymmetric facet coatings have substantially lower threshold current. However, significantly higher front-facet power efficiency is only possible at small grating-coupling coefficients. In particular, the range of loss-coupling coefficients for higher efficiency becomes narrower with larger grating duty cycle and larger index-coupling coefficient. These results can be explained by the interdependence of the reflectivity and extra loss associated with loss-coupled gratings.
Keywords :
antireflection coatings; diffraction gratings; distributed feedback lasers; laser theory; optical couplers; optical films; optical losses; reflectivity; refractive index; semiconductor lasers; above-threshold analysis; above-threshold model; asymmetric facet coatings; extra loss; front-facet power efficiency; higher efficiency; larger grating duty cycle; larger index-coupling coefficient; laser diodes; loss-coupled DFB lasers; loss-coupled gratings; loss-coupling coefficients; perfectly AR-coated devices; power efficiency; reflectivity; small grating-coupling coefficients; threshold current; Coatings; Gratings; Laser feedback; Laser modes; Optical coupling; Photonic integrated circuits; Power generation; Power lasers; Reflectivity; Threshold current;
Journal_Title :
Photonics Technology Letters, IEEE
