Abstract

Because of the low coupling efficiency (10–20%) from a diode laser to a cleaved single-mode optical fiber, discrete lenses or microlens-ended optical fibers have been widely used in laser packaging to obtain more light from the lasers. With both approaches, greater than 50% light coupling can be achieved.^1–3 The microlensed-fiber approach has an advantage of involving fewer parts for alignment in the laser package assembly. In this paper we report, for the first time to our knowledge, the formation of microlenses on the ends of planar-processed silica waveguides. As to the alignment concern for single-laser packaging, these microlensed waveguides will have the same advantage as does the microlensed fibers. For coupling light from arrayed laser diodes, the microlensed waveguides will be easier to work with than are lensed fibers because a waveguide array can be easily fabricated to line up with a laser-diode array. Moreover, we believe that the microlensed waveguides will permit the well-developed silica-waveguide technology to be better utilized in hybrid optoelectronic-integration and fiber-amplifier applications.

© 1995 Optical Society of America