Title :
Extremely small vertical far-field angle of InGaAs-AlGaAs quantum-well lasers with specially designed cladding structure
Author :
Gray Lin ; Shun-Tung Yen ; Chien-Ping Lee ; Der-Cherng Liu
Author_Institution :
Dept. of Electron. Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan
Abstract :
We report on a very small vertical far-field angle achieved by lasers with a specially designed structure. For an InGaAs-AlGaAs quantum-well laser with a 2.5-μm-wide ridge waveguide, the far-field pattern has a vertical far-field angle of 13/spl deg/ and a lateral far-field angle of 8/spl deg/. Meanwhile, the threshold current remains acceptably low (/spl ap/36 mA for a 500-μm-long cavity). The slope efficiency of the L-I characteristic is high (>0.9 W/A) compared to that of the conventional laser.
Keywords :
III-V semiconductors; aluminium compounds; claddings; gallium arsenide; indium compounds; laser cavity resonators; optical transmitters; quantum well lasers; ridge waveguides; waveguide lasers; /spl mu/m-long cavity; /spl mu/m-wide ridge waveguide; 2.5 mum; 36 mA; 500 mum; InGaAs-AlGaAs; InGaAs-AlGaAs quantum-well lasers; L-I characteristic; extremely small vertical far-field angle; far-field pattern; lateral far-field angle; slope efficiency; specially designed cladding structure; threshold current; Fiber lasers; Laser modes; Laser theory; Optical coupling; Optical design; Optical refraction; Optical variables control; Quantum well lasers; Semiconductor lasers; Threshold current;
Journal_Title :
Photonics Technology Letters, IEEE
