Femtosecond pulse delivery around 1560  nm in large-core inhibited-coupling fibers

Dobrakowski D., Rampur A., Stępniewski G., Pysz D., Zhao L., Stepanenko Y., Buczyński R., and Klimczak M.

Journal of the Optical Society of America B

36(11), 2019, 3030-3038, 10.1364/JOSAB.36.003030

Transmission of ultrashort laser pulses under 100 fs at a central wavelength of 1560 nm from a mode-locked laser is investigated over meter-scale lengths of an inhibited-coupling fiber with 65 µm core diameter. Performance of the fiber in this application is evaluated experimentally using cross-correlation frequency-resolved optical gating, either with the fiber loosely coiled up to 3 m of length or bent over one full loop down to 6 cm radius. Experimental results on observed dispersive stretching of the pulse up to around 200 fs are compared with non-linear propagation simulations using the generalized non-linear 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. We show that the proposed fiber can be used to transmit around 90 fs long laser pulses without spectral or temporal distortions, if a 6 cm radius loop is applied.