Manipulating light by microfluidic motion in microstructured optical fibers

We review methods for manipulating light in a microstructured optical fiber by displacing and positioning microfluids along the air-holes of the fiber. To manipulate light propagating in the microstructured optical fiber, we describe two different systems where efficient interaction is obtained between the modal field and microfluids infused in the air-channels. One method involves writing a grating that couples the core to cladding modes whose field distribution is sensitive to the cladding/air-channels interface. The other method consists of tapering the fiber into smaller diameter where the mode field spreads out of the core and into the cladding and becomes sensitive to materials infused into the air-channels. To obtain tunability, microfluidic plugs incorporated into the air-channels of the microstructured optical fiber are displaced along the fiber to overlap with the mode field. In this context we review different applications such as tunable filters/attenuators,polarizers, and periodic gratings. (C) 2003 Elsevier Inc. All rights reserved.