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

In this letter, 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(#)s) as low as f/1.55 and can be fabricated with minimal proc essing steps. Lenses can be fabricated desirably "over-sized," with input a pertures larger than operational beam diameters. The lenses deviate from sp herical by as little as +/- 80 mn over the middle 90% of their surfaces, an d are diffraction limited when used in their paraxial regions. Previous wor k suggests that arrays of such lenses can be fabricated in parallel with go od uniformity (Deltaf/f similar to +/-5.9% for a 15 x 15 array of 500 mum f /1.4 lenses), stability, and reproducibility (average f(#)s are reproducibl e to within 3.5%). Although coupling efficiencies have not been measured, t hese values suggest that the lenses are of sufficient quality for a variety of multimode fiber applications.