Design and Fabrication of a Functional Fiber for Micro Flow Sensing

We designed a novel dual-core fiber with a large side air hole near the center core, which microstructure optical fiber can integrate with microchannel and interferometer in a single fiber. To fabricate this special optical fiber, first, we drill a small hole in the side of a standard single-core fiber preform, insert a thin-clad core preform into the small hole, and then heat and fuse together. Finally, we drilled a larger hole near the center core. In the process of drawing the fiber, the large hole should be filled with nitrogen at a constant pressure to prevent the hole from collapsing. The air hole of the special optical fiber can be used as a channel for microfluidic transmission, and the air hole is in close contact with the central core and away from the eccentric core, so this microstructure optical fiber is very suitable for use as a compact in-fiber integrated microfluidic sensors.