A 40% slope efficiency 790nm pumped 1.9µm Tm3+: ZBLAN directly-written waveguide laser

We report here what we believe to be the highest power (40mW pump power limited) and efficient direct write depressed cladding waveguide laser at a wavelength >;1.6 μm, and the first report of a ZBLAN direct-write waveguide laser. The Tm
³⁺
:ZBLAN glass slab (which is uncoated) is 9mm long, 8mm wide and 2mm high, doped with 2.0 mol% TmF
₃
, and contains 42 depressed cladding waveguides written using a 800nm fs laser.