Title :
Reduction of effective linewidth enhancement factor alpha /sub eff/ of DFB lasers with complex coupling coefficients
Author :
Kudo, Koji ; Shim, Jong In ; Komori, Kazuhiro ; Arai, Shigehisa
Author_Institution :
Dept. of Phys. Electron., Tokyo Inst. of Technol., Japan
fDate :
6/1/1992 12:00:00 AM
Abstract :
The effective linewidth enhancement factor alpha /sub eff/ of DFB lasers which have both gain and index coupling coefficients is theoretically analyzed. The unique reduction mechanism of alpha /sub eff/ due to the optical negative feedback of modal phase and modal gain in gain coupled DFB lasers was found for the first time. The numerical result showed that alpha /sub eff/ can be reduced to almost one half of the material defined linewidth enhancement factor alpha when there exists an index coupling coefficient comparable to the gain coupling coefficient.<>
Keywords :
distributed feedback lasers; feedback; laser theory; optical constants; refractive index; semiconductor junction lasers; spectral line breadth; complex coupling coefficients; effective linewidth enhancement factor; gain coupled DFB lasers; gain coupling coefficients; index coupling coefficients; modal gain; modal phase; optical negative feedback; reduction mechanism; Laser feedback; Laser modes; Laser theory; Negative feedback; Optical coupling; Optical feedback; Optical materials; Optical refraction; Reflectivity; Refractive index;
Journal_Title :
Photonics Technology Letters, IEEE
