Title :
In situ spatially-resolved thermal and brillouin diagnosis of high-power ytterbium-doped fibre laser by brillouin optical time domain analysis
Author :
Jeong, Youngmo ; Jauregui, Cesar ; Richardson, D.J. ; Nilsson, Johan
Author_Institution :
Optoelectron. Res. Centre, Southampton Univ., Southampton
Abstract :
An in situ spatially-resolved diagnosis of thermal and Brillouin characteristics of a double-clad ytterbium-doped fibre (YDF) laser operating at 1.09 mum is demonstrated. For this a Brillouin optical time domain analysis technique based on 1.55 mum Brillouin pump and probe beams is utilised. A 2.4 K temperature difference across the YDF laser when it was running with 6.5 W pump power has been measured and resolved. Based on the measured thermal and Brillouin characteristics of it is expected the YDF, that the effective Brillouin gain coefficient would decrease by 20 for 1.09 m radiation if an 80 K temperature variation is built up across it, as a result of the quantum-heating by the pump power.
Keywords :
Brillouin spectra; fibre lasers; laser beams; laser variables measurement; optical fibre cladding; optical pumping; optical time-domain reflectometry; quantum optics; time-domain analysis; ytterbium; Brillouin optical time domain reflectometry; Brillouin pump power; JkJk:Yb; YDF laser temperature diagnosis; double-clad ytterbium-doped fibre laser operation; laser gain coefficient; optical time domain analysis; power 6.5 W; quantum heating; spatially-resolved Brillouin diagnosis; temperature 2.4 K; temperature 80 K; wavelength 1.09 mum; wavelength 1.55 mum;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:20093465