Silica glass anti-resonant fibers for near- and mid-infrared wavelengths - simulations and test fiber development

Anti-resonant fibers (AR), also called tube lattice fibers (TLF), are novel air-core microstructured fibers. The light in such fibers is guided due to the anti-resonance effect, unlike the photonic bandgap effect used in hollow-core. This AR guiding effect relies on anti-resonance between the mode guided in the centrally located air-core and the modes supported by the cladding, formed by mutually isolated tubes. Due to the high air-filling fraction in AR fibers and the resulting very low interaction of the core mode with glass, they have the potential to effectively guide light at wavelengths even exceeding the glass transmission window. Moreover, the expected nonlinearity of such fibers should be negligible, which creates interesting opportunities for their application in ultrashort laser pulse handling.

Here, we report on numerical simulations of different structures of anti-resonant fibers using a finite difference method. Structures consisting of different number of lattice tubes are compared, with simulations performed under different meshing conditions, and the results are confronted with selected structures of photonic bandgap fibers.

Among simulated tube-lattice fibers, the most interesting ones are with the 7 capillary cladding fibers due to the potential of the lowest losses, having also in some cases better higher-order mode extinction ratio, than fibers with e.g. 6 capillaries. A selected 7-tube structure is optimized for operation at wavelengths exceeding 2 ┬Ám, and the obtainable width of the transmission bands in this spectral area is investigated. Initial test structures of anti-resonant fibers are developed at Institute of Electronic Materials Technology.

Author: Dominik Dobrakowski
Conference: Title