Microlenses self-aligned to optical fibers fabricated using the hydrophobic effect

We report a means of fabricating microlenses on transparent spacers that are self-aligned to optical fibers. The lenses so formed have f-numbers (f/sup /s) as low as f/1.55 and can be fabricated with minimal processing steps. Lenses can be fabricated desirably "over-sized," with input apertures larger than operational beam diameters, The lenses deviate from spherical by as little as /spl plusmn/80 nm over the middle 90% of their surfaces, and are diffraction limited when used in their paraxial regions. Previous work suggests that arrays of such lenses can be fabricated in parallel with good uniformity (/spl Delta/f/f/spl sim//spl plusmn/5.9% for a 15×15 array of 500 μm f/1.4 lenses), stability, and reproducibility (average f/sup /s are reproducible to within 3.5%). Although coupling efficiencies have not been measured, these values suggest that the lenses are of sufficient quality for a variety of multimode fiber applications.