The development of negative curvature fibers is an exciting advance in optical fiber technology that combines relatively low loss over a broad bandwidth with relatively high tolerance for fabrication imperfections. Tolerance of fabrication imperfections is particularly important for chalcogenide fibers, and negative curvature geometries have made it possible to fabricate hollow-core chalcogenide fibers that can transmit light at 10 μm with a loss of 2.1 dB/m. We review theoretical and experimental work that we have carried out to determine the performance limits and to design and fabricate chalcogenide negative curvature fibers.
The coupling characteristics of fluid-filled dual-core photonic crystal fibers are numerically investigated. The
transmission spectrum is obtained in different temperatures. With the help of a vector finite element method we acquire
the properties of the minimum coupling length. Finally, the coupling characteristic is experimental studied by the way of