Single-mode UV-written buried channel waveguide lasers in direct-bonded neodymium-doped SGBN

Summary form only given. We present the first demonstration of single-mode buried channel waveguide lasers in neodymium-doped SGBN glass by a combination of direct bonding and direct UV writing techniques. Based on intersubstrate ion-exchange between specifically designed glass substrate materials we have used direct bonding to provide a region of atomic contact between Nd:SGBN and a potassium-rich borosilicate cladding substrate, between which K/sup +/-Na/sup +/ ion-exchange can occur. By taking this approach we have achieved a low-loss buried planar waveguide layer in the Nd:SGBN glass, which retains the photosensitive characteristics of the bulk material and into which single-mode channel waveguide structures can be directly written using a focussed UV beam. For this initial demonstration, a Nd:SGBN substrate containing SiO/sub 2/ (60 wt.%), GeO/sub 2/ (10 wt.%), B/sub 2/O/sub 3/ (10 wt.%), Na/sub 2/O (19 wt.%), and Nd/sub 2/O/sub 3/ (1 wt.%), was prepared and direct-bonded to a potassium-rich glass of similar composition to BK-7. Characterization of the 7.5-mm-long buried channel laser waveguide device was performed using a Ti:sapphire laser operating at 808 nm. The resultant 1059 nm laser output exhibited milliwatt-order laser thresholds, single-mode operation, propagation losses of <0.3 dB cm/sup -1/, and a maximum output power of 2 mW for 32 mW of absorbed pump power. These initial results demonstrate that optimisation of glass composition and direct UV writing parameters could lead to efficient low-loss buried waveguide devices in versatile bulk multicomponent oxide glasses for use with integrated optics.