Square and hexagonal shaped hollow-core optical fibers – Novel design variations for antiresonant sensor waveguides

Large-mode optical glass fibers with hollow-core structures are promising candidates for various chemical analytical applications, e. g. UV-VIS-NIR absorption or RAMAN scattering spectroscopy. We report on design and manufacturing of new types of polygonal shaped hollow-core fibers based on antiresonant fiber concepts. In contrast to typical photonic band gap fibers these fibers are characterized by large hollow cores with about 30 µm cross section, which can be easily filled with gaseous and liquid analytes. A further advantage of the fiber design concept is its simple structure, characterized by a minimum of web bridges. We demonstrate two fiber types with square and hexagonal hollow core. In addition, we discuss correlation effects between preparation aspects (e.g. thinness and homogeneity of bridges) und optical behavior (spectral loss, spectral position of antiresonant light guiding bands, etc.).The novel fibers exhibit effective single-mode operation in several transmission bands from the near infrared to the deep UV-range with minimum attenuations of about 2 dB/m.