Thickness Profile Simulation of Narrow Stripe Selective MOVPE and Its Application to Spot-Size-Converter Integrated Laser Diodes

Hiroyuki YAMAZAKI  Yasutaka SAKATA  Tomoaki KOUI  Kohro KOBAYASHI  

C - Abstracts of IEICE TRANSACTIONS on Electronics (Japanese Edition)   Vol.J91-C   No.5   pp.279-287
Publication Date: 2008/05/01
Online ISSN: 1881-0217
Print ISSN: 1345-2827
Type of Manuscript: PAPER
crystal growth,  selective MOVPE,  semiconductor laser,  spotsize-converter,  

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Narrow stripe selective MOVPE, which enables in plane band-gap energy control as well as waveguide thickness control, is attractive for fabrication of monolithically integrated photonic devices. For example, a spot-sizeconverter integrated laser diode (SSC-LD) requires precise profile control in order to obtain excellent lasing and coupling characteristics without additional coupling lens. In this paper, we present a simple model for selective MOVPE taking into account the vapor phase diffusion and the geometry design of the photomask. A three dimensional beam propagation method for the coupling characteristics and a density matrix theory for the optical gain spectrum has been applied to determine the optimum thickness taper profile for SSC-LDs. Furthermore, the optimum mask pattern was synthesized by iterative calculation using this model. We have demonstrated excellent agreement between experiments and numerical simulations, and have confirmed the advantage of our proposed method. We believe this method is very useful for the mask design of selective MOVPE in order to improve characteristics not only for SSC-LDs but also for other monolithically integrated photonic devices such as modulator integrated DFB lasers, wavelength tunable lasers and so on.