Title :
Improvement of single-mode gain margin in gain-coupled DFB lasers
Author :
Chen, Jianyao ; Champagne, Alain ; Maciejko, Romas ; Makino, Toshihiko
Author_Institution :
Optoelectron. Lab., Ecole Polytech., Montreal, Que., Canada
fDate :
1/1/1997 12:00:00 AM
Abstract :
Using the Bloch-wave analysis, this paper investigates the effect of the gain grating on the single-mode condition in DFB lasers. Various factors affecting the threshold gain of gain-coupled DFB lasers are analyzed in some detail. It is shown for the first time that unequal section lengths in the gain grating can have a significant effect on the single-mode gain margin of gain-coupled DFB lasers, especially when the linewidth enhancement factor αM is large, because the long and shortwavelength Bloch waves are in phase and in antiphase with the index grating of DFB lasers, respectively
Keywords :
diffraction gratings; distributed feedback lasers; laser modes; laser theory; semiconductor device models; semiconductor lasers; spectral line breadth; Bloch-wave analysis; antiphase; gain grating; gain-coupled DFB lasers; index grating; linewidth enhancement factor; longwavelength Bloch waves; shortwavelength Bloch waves; single-mode condition; single-mode gain margin; threshold gain; unequal section lengths; Coatings; Distributed feedback devices; Fiber lasers; Gratings; Laser feedback; Laser modes; Optical coupling; Optical feedback; Periodic structures; Semiconductor lasers;
Journal_Title :
Quantum Electronics, IEEE Journal of
