Hollow multilayer photonic bandgap fibers for NIR applications.

Here we report the fabrication of hollow-core cylindrical photonic bandgap fibers with fundamental photonic bandgaps at near-infrared wavelengths, from 0.85 to 2.28 microm. In these fibers the photonic bandgaps are created by an all-solid multilayer composite meso-structure having a photonic crystal lattice period as small as 260 nm, individual layers below 75 nm and as many as 35 periods. These represent, to the best of our knowledge, the smallest period lengths and highest period counts reported to date for hollow PBG fibers. The fibers are drawn from a multilayer preform into extended lengths of fiber. Light is guided in the fibers through a large hollow core that is lined with an interior omnidirectional dielectric mirror. We extend the range of materials that can be used in these fibers to include poly(ether imide) (PEI) in addition to the arsenic triselenide (As(2)Se(3)) glass and poly(ether sulfone) (PES) that have been used previously. Further, we characterize the refractive indices of these materials over a broad wavelength range (0.25 - 15 microm) and incorporated the measured optical properties into calculations of the fiber photonic band structure and a preliminary loss analysis.