Open AccessMultimode LD-pumped all-fiber Raman laser with excellent quality of 2nd-order Stokes output beam at 1019 nm
Author(s) -
A. G. Kuznetsov,
Ilya N. Nemov,
Alexey A. Wolf,
S. I. Kablukov,
Sergey A. Babin
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.425639
Subject(s) - optics , multi mode optical fiber , materials science , slope efficiency , fiber laser , laser beam quality , laser , raman spectroscopy , raman laser , fiber bragg grating , fiber , optical fiber , raman scattering , optoelectronics , laser beams , physics , composite material
A multimode all-fiber Raman laser enabling cascaded generation of high-quality 1019-nm output beam at direct pumping by highly-multimode (M 2 >30) 940-nm laser diodes has been demonstrated. The laser is made of a 100/140 graded-index fiber with special in-fiber Bragg gratings which secure sequential generation of the 1 st (976 nm) and 2 nd (1019 nm) Stokes orders. Comparing different 1019-nm cavity structures shows that the half-open cavity with one FBG and distributed feedback via random Rayleigh backscattering provides excellent quality (M 2 ∼1.3) with higher slope efficiency of pump-to-2 nd Stokes conversion than in the conventional 2-FBG cavity. The maximum achieved slope efficiency amounts to about 40% at output powers of up to 12 W limited by the 3 rd Stokes generation.