Fabrication tolerances in fibre directional couplers designed to maximise coupling between fibres and diode lasers

Author

Leaver, K.D. ; Pagiatakis, G.

Author_Institution

Dept. of Electr. Eng., Imperial Coll. of Sci., Technol. & Med., London, UK

Volume

141

Issue

1

fYear

1994

fDate

2/1/1994 12:00:00 AM

Firstpage

69

Lastpage

74

Abstract

A fibre directional coupler is described that comprises one fibre with a circular core coupled to one with a suitable rectangular core, which makes it possible in principle to couple 100% of the output of a semiconductor laser or laser amplifier into a single-mode communications fibre, and vice versa. The manufacture of such a coupler depends critically on the control of dimensions, because of the differing dispersion characteristics of the two fibres. This coupler was modelled using a finite element program in a preliminary attempt to study dimensional tolerances, with a view to optimising its design. Calculations are presented of the beatlength as a function of the sizes and the refractive indices of the two cores comprising the coupler, together with estimates of the dimensional tolerances, giving coupling losses under 1 dB

Keywords

directional couplers; optical couplers; optical design techniques; optical dispersion; optical fibres; optical losses; 1 dB; beatlength; circular core; coupling losses; design optimisation; dimensional tolerances; diode lasers; dispersion characteristics; fabrication tolerances; fibre coupling; fibre directional couplers; finite element program; laser amplifier; rectangular core; refractive indices; semiconductor laser; single-mode communications fibre;

fLanguage

English

Journal_Title

Optoelectronics, IEE Proceedings -

Publisher

iet

ISSN

1350-2433

Type

jour

DOI

10.1049/ip-opt:19949848

Filename

278121