Fabrication of Buried Heterostructure Spot-Size Converter Lasers

• Main Authors: Tsung-Hsien Wu, 吳宗憲
• Other Authors: Tsong-Sheng Lay
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/73388652702525184091

碩士 === 國立中山大學 === 光電工程研究所 === 88 === We present the fabrication of InGaAsP/InP buried heterostructure spot-size converter lasers. In the lateral conversion, we use photolithography to make tapered ridge waveguides. In the vertical conversion, we use a pair of step-index passive waveguides, namely guard waveguides (GWs), in the two sides of the step-index active waveguide region to increase optical-field profile. In order to decrease leakage current, we use a p-n-p current blocking structure by MOCVD regrowth. From numerical simulations, the far-field divergence is 21x21. The step-index GW structure shows an internal efficiency of 63%. However, the BH lasers did not lase from our fabrication processes. From the I-V characteristics, a large leakage current has bypassed through the blocking structure. The reason may relate to the high background doping concentration of our MOCVD growth.