Abstract

High power broadband superfluorescent sources operating in the 2 μm spectral region have many applications including spectroscopy, gas sensing and medical imaging via optical coherence tomography. Over the last few years there has been very rapid progress in scaling the output power from cladding-pumped Tm-doped fibre lasers, but rather less attention has been paid to broadband 2 μm sources. The first Tm-doped fibre-based superfluorescent source at 1.91 μm was demonstrated with ~ 1 mW output power and a bandwidth of 77nm [1], Very recently, a broadband 2 μm source with a higher output power of ~100mW and a bandwidth of 40 nm based on a Tm-doped fibre was reported [2], but with a relatively low slope efficiency of ~ 3%. In this paper, we report a highly-efficient double-ended broadband 2 μm cladding-pumped Tm-doped superfluorescent fibre source with much higher output power. Over 15 W of combined output power was generated for a launched pump power of 50.3 W. The corresponding slope efficiency with respect the launched pump power was 42%. The bandwidth (FWHM) of the emission spectrum was ~ 282 nm at an output power of 8 mW and ~45nm at the highest output power of 15 W.

© 2007 IEEE