Title :
Design of a spotsize-converter-integrated laser diode (SS-LD) with a lateral taper, thin-film core and ridge in the 1.3-μm-wavelength region based on the 3-D BPM
Author :
Kawano, Kenji ; Kohtoku, Masaki ; Wada, Masato ; Okamoto, Hiroshi ; Itaya, Yoshio ; Naganuma, Mitsuru
Author_Institution :
NTT Opto-Electron. Labs., Kanagawa, Japan
fDate :
6/1/1996 12:00:00 AM
Abstract :
In order to develop spotsize-converter-integrated laser diodes (SS-LDs) with high efficiency and large-misalignment tolerances in the 13-μm-wavelength region, spotsize converters (SSCs), which consist of lateral taper, thin-film core and ridge, are investigated employing the three-dimensional (3-D) semivectorial finite-difference beam propagation method (FD-BPM) with nonequidistant discretization. The sum of the spot-conversion loss and coupling loss between the laser diode (LD) eigenmode and the single-mode fiber (SMF) eigenmode are calculated for various structural parameters. Small loss of around 1.5 dB can be achieved by introducing a nonlinear taper. The fabrication tolerances for the SSCs are also clarified. The calculated results agree well with the results for actually fabricated SS-LD´s. It is also shown that the radiation loss and coupling characteristics of the SS-LDs with a buried thin-film core structure can be improved using a nonlinear taper
Keywords :
convertors; finite difference methods; integrated optics; laser transitions; optical design techniques; optical fabrication; optical fibre couplers; optical losses; quantum well lasers; 1.3 mum; 1.5 dB; 3-D BPM; LD eigenmode; MQW active layer; SS-LD; buried thin-film core structure; coupling characteristics; coupling loss; design; fabrication tolerances; high efficiency; large-misalignment tolerances; lateral taper; nonequidistant discretization; nonlinear taper; ridge; single-mode fiber eigenmode; spot-conversion loss; spotsize-converter-integrated laser diode; structural parameters; thin-film core; three-dimensional semivectorial finite-difference beam propagation method; Diode lasers; Nonlinear optics; Optical coupling; Optical design; Optical device fabrication; Optical devices; Optical losses; Optical switches; Optical waveguides; Transistors;
Journal_Title :
Selected Topics in Quantum Electronics, IEEE Journal of
DOI :
10.1109/2944.577394
