MOVPE Grown BH-LD's Novel Self-Alignment Process

Abstruct- 1.3 pm-strained MQW BH LD's with a current blocking structure have been developed by selective MOVPE and a newly developed self-alignment process; we call these devices ASM (all selective MOVPE grown)-BH-LD's. The fabrication process, which completely eliminates semiconductor etching, is very promising to realize high-performance LD's with excellent uniformity and reproducibility. The light output power was remarkably improved by a factor of two, compared with previous selective MOVPE-LD's. OR the deployment of optical subscriber systems, high F performance laser diodes (LD's) fabricated with a cost- effective process are in high demand. In the conventional fabrication process of buried heterostructure (BH) LD's, active mesa stripes are formed by semiconductor etching followed by a regrowth process, but this is detrimental to LD uniformity and reproducibility. An alternative is selective MOVPE. With this technique, no semiconductor etching process is required, and LD's can be obtained with high uniformity and repro- ducibility. Selective MOVPE has been already demonstrated as a powerful technique in the fabrication of advanced optical devices ( 11-(3). For example, highly uniform LD character- istics have been demonstrated for selectively grown tunable DBR-LD's (4) and also for a low threshold 17-channel array of narrow active stripe LD's (5). However, due to the lack of a current blocking structure, the maximum output power of LD's has been limited to less than 20 mW. In this paper we demonstrate newly developed all-selective- MOVPE-grown (ASM)-BH LD's with a current blocking structure. The device fabrication process, completely void of semiconductor etching, consists of selective MOVPE and a self-alignment mask patterning process. A more than two-fold light output power, compared with previous selectively grown LD's, has been obtained for 1.3 pm-strained MQW-BH-LD's fabricated with this new process.