Towards integration of a liquid-filled fiber capillary for supercontinuum generation in the 12–24 μm range

We demonstrate supercontinuum generation in unspliced as well as in integrated CS(2)-filled capillary fibers at different pump wavelengths of 1030 nm, 1510 nm, and 1685 nm. A novel method for splicing a liquid-filled capillary fiber to a standard single-mode optical fiber is presented. This method is based on mechanical splicing using a direct-laser written polymer ferrule using a femtosecond two-photon polymerization process. We maintain mostly single-mode operation despite the multi-mode capability of the liquid-filled capillaries. The generated supercontinua exhibit a spectral width of over 1200 nm and 1000 nm for core diameters of 5 μm and 10 μm, respectively. This is an increase of more than 50 percent compared to previously reported values in the literature due to improved dispersion properties of the capillaries.