Monolithic integration of lasers and passive elements using selective QW disordering by rapid thermal annealing with SiO2 caps of different thicknesses

We have investigated the use of rapid thermal annealing of InGaAs strained quantum well structures through SiO2 caps with two different thicknesses to selectively disorder the quantum well, as a way to implement the monolithic integration of low-loss passive devices such as optical waveguides with quantum well lasers. In these investigations, we first selectively disordered a quantum well by depositing a 300-nm SiO2 cap in one region and a 30-nm SiO2 cap in another region, followed by rapid thermal annealing. We then fabricated lasers in the two regions, and found that the oscillation wavelengths of lasers fabricated in the region with the 300-nm SiO2 cap differed from the oscillation wavelengths of those in the region with the 30-nm SiO2 cap. By using this technique to integrate passive waveguides with a Fabry-Perot laser, we were able to evaluate the optical loss in the passive waveguides. We found that we could reduce the loss by a large amount, from 40 cm−1 for the case of no disordering to only 3 cm−1. We also fabricated a distributed Bragg reflector laser using selective disordering of the quantum well in the grating region, and succeeded in obtaining a remarkable improvement in the laser characteristics compared to those of an undisordered laser. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(1): 34–42, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10039