Femtosecond pulse delivery around 1560 nm in large-core anti-resonant fibers

Hollow core, anti-resonant fiber with 65 μm core diameter is used for transmission of ultrashort laser pulses under 100 fs at a central wavelength of 1560 nm from a mode-locked laser. Meter-scale lengths of the fiber (up to 3 m) and bend radii down to 6 cm are considered. Cross-correlation frequency-resolved optical gating is used for investigation of performance of the fiber in this application. Achieved results on dispersive stretching of the pulse up to around 200 fs are compared with nonlinear propagation simulations, performed using the generalized nonlinear Schrödinger equation parametrized with measured characteristics of the fiber. Dechirping of the pulse to its original shape in the fiber under bending is observed and related to suppression of higher-order modes. As shown, the proposed fiber can be used to transmit sub-100 fs long laser pulses without spectral or temporal distortions providing a 6 cm radius loop.