ION-IMPLANTED WAVE-GUIDE LASERS IN INSULATORS

Optical confinement within a waveguide structure favours efficient operation of both laser and second harmonic light sources. Typical waveguides are of the order of a few microns thick. This depth of material can be influenced by ion implantation by adding dopants or by using radiation damage to define a low refractive ind'' optical barrier. Such a confinement route is widely applicable and has been used in some 40 insulator materials. Of these seven have been operated as lasers and a further five for second harmonic generation. Pump to laser output efficiencies in both cases have exceeded 30%, and for channel guides the laser thresholds can be as low as a milliwatt. Ion implantation doping using rare earth ions is equally attractive, but at present the guide losses have inhibited lasing in the examples attempted. The current state of the art and future laser possibilities are discussed.