Dispersion measurement of microstructured negative curvature hollow core fiber

We present measurements of the dispersion of two negative curvature fibers at and around 1  μm. These fibers are suitable for beam delivery of both high power and ultrashort pulse lasers with one designed to operate at 1030 nm and the other designed for dual wavelength delivery at 515 and 1030 nm. Both fibers were found to exhibit anomalous dispersion measured to be 2.17±0.25  ps nm−1 km−1for the fundamental mode rising to 4.69±0.17  ps nm−1 km−1 for the first-order mode in the 1030-nm fiber. Dispersion in the double wavelength fiber was found to be higher at 3.81±0.03  ps nm−1 km−1 for the fundamental mode guiding at 1030 nm.