A batch-fabricated microball lens array not only provides accurate coupling distances but also replaces traditional components such as aspheric lenses and expensive graded-index lenses without sacrificing performance and reduces assembly cost. The results of extensive experiments show a critical aspect ratio of ~0.3. That is, when the aspect ratio is larger than 0.3, the final shape of a reflowed lens changes to that of a microball rather than of a mushroom. Using a laser with a 633-nm wavelength yields an optimum coupling distance of ~8 μm with an insertion loss below −1.3 dB (coupling efficiency, ~73%).
© 2004 Optical Society of America
(120.4610) Instrumentation, measurement, and metrology : Optical fabrication
(140.7240) Lasers and laser optics : UV, EUV, and X-ray lasers
(220.3630) Optical design and fabrication : Lenses
Cheng-Tang Pan, Chi-Hui Chien, and Chi-Chang Hsieh, "Technique of Microball Lens Formation for Efficient Optical Coupling," Appl. Opt. 43, 5939-5946 (2004)