Coupled-mode analysis of highly asymmetric directional couplers with periodic perturbation

Author

Borges, B.-H.V. ; Herczfeld, P.R.

Author_Institution

Sao Paulo Univ., Brazil

Volume

46

Issue

3

fYear

1998

fDate

3/1/1998 12:00:00 AM

Firstpage

215

Lastpage

226

Abstract

This paper presents an in-depth analysis of highly asymmetric grating assisted directional couplers. The directional coupler consists of a polymer waveguide with dimensions and refractive indices closely matching a single-mode fiber fabricated atop a Ga_0.6Al_0.4As/GaAs/Ga_0.4Al_0.6As waveguide. The structure is investigated analytically by means of a new orthogonal coupled-mode theory formulated in terms of the Lorentz reciprocity theorem. For the first time, the analysis includes three distinct loss mechanisms, namely, the leakage of power toward the semiconductor substrate, the power lost to radiation modes (mode mismatching), and the grating radiation loss

Keywords

Lorentz transformation; coupled mode analysis; directional couplers; optical fibre couplers; optical fibre losses; refractive index; Ga_0.6Al_0.4As-GaAs-Ga_0.4Al _0.6As; Lorentz reciprocity theorem; asymmetric directional couplers; coupled-mode analysis; grating assisted directional couplers; grating radiation loss; loss mechanisms; mode mismatching; orthogonal coupled-mode theory; periodic perturbation; polymer waveguide; radiation modes; refractive indices; single-mode fiber; Coupled mode analysis; Directional couplers; Gratings; Optical fiber couplers; Optical fibers; Optical waveguides; Polymers; Rectangular waveguides; Semiconductor waveguides; Substrates;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/22.661706

Filename

661706