high and anti-reflection facet coating of high power GaAs/AlGaAs single quantum well lasers

• Main Authors: Chuang, ming nan, 莊敏男
• Other Authors: Kouchou Tai
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/61460001912499173835

碩士 === 國立交通大學 === 光電工程研究所 === 84 === In this thesis, we present our study on the facet coating of high power GaAs/AlGaAs lasers. Performance of the high power lasers is improved by coatings the combination of AR and HR to the two facets using E-beam evaporation. Anti-reflectivity coating which consist of a single (/4 thick SiO2 film is deposited to the front facet (the emission facet) to reduce its reflectivity from 31% (as-cleaved facet) to 6%. High reflectivity coating which consists of 3 pairs of quarter wave SiO2/TiO2 stacks on the back facet to increases the reflectivity to more than 92%. The combination of AR and HR coating increases the differential quantum efficiency of light output from the front facet from the uncoated value 0.55 W/A to 1.1 W/ A. The output power reaches as high as 2W at room temperature at 2.5 A. The threshold current changes only slightly from 235 mA to 260 mA. The front facet external quantum efficiency has increased from 0.37 to 0.72. The front facet wall plug efficiency has increased from 0.225 to 0.37.