Developing Tapered Fiber Devices

Tapered fibers with diameter on the order of one micrometer have attracted much attention during the last years. Due to the small cross section of the tapered fiber, a denoting amount of the electric field propagates outside the physical boundary of the fiber and is called the evanescent field. This field can be accessed rather easily for interaction with the environment and offers high light intensity because of the strong spatial confinement. We present two optical devices which are based on tapered fibers manufactured by a CO2 laser beam fabrication technique. 

The first device is a fiber knot with sub millimeter dimensions, where we fused the knot with a laser beam. Our post-fabrication fusing process of the micro-knot overcomes the drawbacks of fiber micro-knot and improves its robustness and stability.

The second device is a strong long period fiber grating, operating in off-resonance conditions. Our method of writing these long period fiber gratings is based on utilizing the mechanical vibrations of tapered fibers during the tapering process.

* This research was carried out towards the Masters degree in Electrical Engineering at Bar-Ilan University, under the supervision of Dr. Moti Fridman