Title :
Ray optics determination of the DFB coupling coefficient for trapezoidal gratings
Author :
Cho, Sung-Chan ; Kim, Boo-Gyoun ; Dagli, Nadir
Author_Institution :
Dept. of Electron. Eng., SoongeSil Univ., Seoul, South Korea
fDate :
4/1/1998 12:00:00 AM
Abstract :
A ray optics technique is used to derive a closed-form expression for the first-order coupling coefficient of trapezoidal gratings in a generic five-layer separate confinement heterostructure distributed feedback (DFB) laser configuration for transverse electric (TE) mode. Expressions for a rectangular grating with the duty cycle of 0.5 and a symmetric triangular grating are also obtained as special cases of our general expressions. Based on the comparison of the coupling coefficient calculated by the ray optics technique with those calculated by the extended additional layer method, we show that the ray optics technique is very useful to calculate the coupling coefficient for most cases of realistic grating depths and profiles used in multilayer DFB devices without using any numerical techniques
Keywords :
diffraction gratings; distributed feedback lasers; laser modes; laser theory; optical films; ray tracing; semiconductor device models; semiconductor lasers; DFB coupling coefficient; TE mode; closed-form expression; coupling coefficient; duty cycle; extended additional layer method; first-order coupling coefficient; generic five-layer separate confinement heterostructure DFB laser configuration; grating depths; multilayer DFB devices; ray optics determination; ray optics technique; rectangular grating; semiconductor lasers; symmetric triangular grating; trapezoidal gratings; Charge carrier processes; Closed-form solution; Distributed feedback devices; Gratings; Laser feedback; Laser modes; Optical coupling; Optical devices; Optical feedback; Tellurium;
Journal_Title :
Lightwave Technology, Journal of
