Design and analysis of high coupling efficiency spot-size converter integrated laser diodes by three-dimensional BPM

This paper discusses the coupling characteristics of a high-temperature high-output 1.3-mu m-band SS-LD, which has a spot-size conversion function realizing high coupling efficiency and helps to reduce the assembly cost of optoelectronic modules. It is intended to realize simultaneously two types of laser performance, namely, strictly high-temperature high-output, as well as high-level spot-size conversion. The butt-joint SS-LD is considered, in which these two capabilities can be optimized independently. As a means of design of waveguides to improve coupling efficiency, a three-dimensional BPM that can flexibly deal with the pn-embedded structure and with composition varying in the direction of propagation are used. Assuming that the waveguide is to be formed by the selective growth technique, we discuss a design in which the process conditions, such as the composition of the waveguide or the fabrication accuracy of the mesa width, are relaxed, and a high coupling efficiency (with a coupling loss of 2 dB or less) is achieved. (C) 1999 Scripta Technica.