Fabrication of Microlenses on Optical Fibers

This work presents mechanical nano-grinding as an alternative technique for the fabrication of optical fibers endface microlenses. It also presents a novel surface-roughness improvement technique called Loose Abrasive Blasting (LAB). Traditionally, the majority of such microlenses are made using either chemical etching or heating and pulling methods. Despite the success of these methods, they suffer some common drawbacks such as the lack of controllability on the produced lens profile. Consequently the possible variations of lens profiles that can be made by these methods are also limited. Using nanogrinding, it was possible to produce a multitude variety of lens profiles with high profile accuracy and with surfaces of optical quality without the need for exposure to any kind of hazardous chemicals. Nanogrinding experiments were conducted on a nano-grinding machine (NGM) specially built for this purpose. The machine incorporates state-of-the-art air-bearing spindles, piezo electric actuators, and capacitive displacement sensors with accuracy down to 2 nm. Such precise motion provided by this system is the key for the success of this technique.