Effect of laser phase noise in Sagnac interferometers

Author

Kråkenes, Kjell ; BlØtekjaer, Kjell

Author_Institution

Dept. of Electr. Eng. & Comput. Sci., Norwegian Inst. of Technol., Trondheim, Norway

Volume

11

Issue

4

fYear

1993

fDate

4/1/1993 12:00:00 AM

Firstpage

643

Lastpage

653

Abstract

A theoretical analysis of the responsivity and the noise caused by backscattering in a Sagnac interferometer used as a sensor for reciprocal measurands, such as acoustic waves, is presented. Both Rayleigh backscattering and reflections from splices are taken into account. The noise power is found to increase proportionally to the source coherence time, and a noise equivalent phase shift in the range of 0.1×10^-6 rad r.m.s./Hz^1/2 is predicted for typical fibers and diode lasers. Experimentally, a noise equivalent phase shift of 2.5×10^-7 rad r.m.s./Hz^1/2 at 10 kHz was observed, with a detector current of 3 μA

Keywords

Rayleigh scattering; backscatter; fibre optic sensors; light interferometers; semiconductor device noise; 10 kHz; 3 muA; Rayleigh backscattering; Sagnac interferometers; acoustic waves; backscattering; detector current; diode lasers; fibre-optic interferometers; laser phase noise; noise equivalent phase shift; noise power; reciprocal measurands; reflections; responsivity; source coherence time; splices; Acoustic measurements; Acoustic noise; Acoustic sensors; Acoustic waves; Backscatter; Laser noise; Laser theory; Noise measurement; Phase noise; Sagnac interferometers;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/50.248130

Filename

248130