Temporal instabilities in the output of a high power Tm-doped double-clad silica fibre laser

Summary form only given. We have recently reported the operation of a high power diode-pumped Tm-doped silica fibre laser capable of producing >5 W output power at slope efficiencies of 31%. Using the double-clad pumping arrangement allows the use of high power diode lasers (operating at 790 nm) to efficiently excite Tm/sup 3+/ ions into the /sup 3/F/sub 4/ energy level and because of the relatively fast multiphonon relaxation down to the /sup 3/H/sub 4/ upper laser level, an efficient /spl sim/2 /spl mu/m laser source is produced.