Accurate modeling and measurement of pressure-induced group velocity dispersion variations in anti-resonant hollow-core fibers

Precise control of group velocity dispersion (GVD) by pressure in a gas-filled hollow-core fiber (HCF) is of essential importance for many gas-based nonlinear optical applications. To accurately calculate the pressure-induced dispersion variations (∂β2/∂p) in anti-resonant types of HCF, an analytical model combining the contribution of the gas material, capillary waveguide, and cladding resonances is developed, with an insightful physical picture. Broadband (∼1000 nm) GVD measurements in a single-shot manner realize accuracy and precision as low as 0.1 ps2/km and 2 × 10-3 ps2/km, respectively, and validate our model. Consistent with our model, a pronounced negative ∂β2/∂p is observed experimentally for the first time, to our knowledge. Our model can also be extended to other HCFs with cladding resonances in predicting ∂β2/∂p, such as in photonic bandgap types of HCF.