We report what is to our knowledge the first operation of a planar dielectric tapered-waveguide laser. The waveguide laser is fabricated by potassium-ion exchange in Nd<sup>3+</sup> -doped BK7 glass and consists of a single-mode channel waveguide of a few micrometers' width followed by a linear taper up to a broad region with a width of ∼180µm . A slope efficiency of 42% is found both in the tapers and in standard channel waveguides fabricated upon the same substrate, indicating that the tapers and the channels have similar internal losses; hence the low-loss nature of the tapered beam expansion. The output from either end of the tapered structure is found to be nearly diffraction limited.
© 2000 Optical Society of America
(140.3410) Lasers and laser optics : Laser resonators
(140.3460) Lasers and laser optics : Lasers
(140.3580) Lasers and laser optics : Lasers, solid-state
(230.7370) Optical devices : Waveguides
S. J. Hettrick, J. I. Mackenzie, R. D. Harris, J. S. Wilkinson, D. P. Shepherd, and A. C. Tropper, "Ion-exchanged tapered-waveguide laser in neodymium-doped BK7 glass," Opt. Lett. 25, 1433-1435 (2000)