Beam quality factor of higher order modes in a step-index fiber

Author

Yoda, Hidehiko ; Polynkin, Pavel ; Mansuripur, Masud

Author_Institution

Fac. of Eng., Utsunomiya Univ.

Volume

24

Issue

3

fYear

2006

fDate

3/1/2006 12:00:00 AM

Firstpage

1350

Lastpage

1355

Abstract

The beam quality factor (or M²-parameter) for linearly polarized (LP)-modes of a step-index fiber is calculated in a closed form, as a function of the fiber V-number. It is shown that M² sharply peaks for all fiber modes when they are close to cutoff. Particularly simple expressions are derived in the limit Vrarrinfin. Two practically important coherent superpositions of modes are considered for which the degree of degradation of the beam quality due to the higher order mode content is calculated. The reported results can be useful for designing large-core high-power fiber lasers, amplifiers, and fiber-based beam delivery systems, when preservation of the spatial beam quality is important

Keywords

Q-factor; laser beams; optical fibre amplifiers; optical fibre polarisation; beam quality factor; coherent mode superpositions; fiber V-number; fiber amplifiers; fiber-based beam delivery systems; high order modes; high-power fiber lasers; large-core fiber lasers; linearly-polarized modes; spatial beam quality; step-index fiber; Degradation; Fiber lasers; High power fiber lasers; Laser beams; Laser modes; Optical beams; Optical design; Optical fiber polarization; Optical fibers; Q factor; Beam quality factor; fiber modes; multimode fiber;

fLanguage

English

Journal_Title

Lightwave Technology, Journal of

Publisher

ieee

ISSN

0733-8724

Type

jour

DOI

10.1109/JLT.2005.863337

Filename

1605337