Proceedings Article | 25 May 2022
KEYWORDS: Optical fibers, Fabrication, Telecommunications, Single mode fibers, Polymers, Polymer optical fibers, Polishing, Objectives, Metrology, Materials processing
Lensed optical fibers are required to collect, focus, or collimate light in many modern applications. This is the case for a wide range of applications, such as telecommunication, metrology, or material processing. To shape the fiber tip, many techniques of micro-lens fabrication exist. However, they all have limitations. The fiber tip can be melted using electric arc, or laser. It can also be mechanically polished or etched using dry or wet processes. Photo-polymerization, 3D-printing and lithography can also be used. Some of these techniques are quite easy to implement but allow a limited shape diversity to be realized. Some others are very accurate with a large variety of possible lens shapes. However, they are costly and require sophisticated equipment. The higher difficulty is undeniably for high curvature micro-lenses for fibers with small core diameters. Consequently, having the ability to simply fabricate a micro-lens for all kinds of fibers has been the focus of our newly developed technique. This technique is polymer based, and, using an optical self-alignment system, we are able to fabricate micro-lenses for multimode as well as for single mode fibers. This technique is not only compatible with all fiber types, but it also grants the ability to manipulate the size and geometry of the micro-lens, therefore giving control over the focalized spot size. Diffraction limited or even smaller spots can be easily obtained, especially by using high-curvature small-base micro lenses. Several examples will be presented: the fabricated micro-lenses, their theoretical behavior, their experimental characterizations, and their potential applications.
