Silica-based photonic crystal fiber infiltrated with 1,2-dibromoethane for supercontinuum generation

Van H.L., Hoang V.T., Canh T.L., Dinh Q.H., Nguyen H.T., Minh N.V.T., Klimczak M., Buczynski R. and Kasztelanic R.

Applied Optics

60(24), 2021, 7268-7278, 10.1364/AO.430843

This study proposes a photonic crystal fiber (PCF) made of fused silica glass with the core infiltrated with 1,2-dibromoethane (C2H4Br2) as a new source of supercontinuum light pulses. Due to the modifications of the PCF’s structure geometry, a number of computer simulations investigating their optimized structures has been carried out. This aimed at achieving flat near-zero dispersion and zero dispersion wavelength matching of the pump wavelength for efficient spectral broadening. Based on the obtained results, the structural geometries of two C2H4Br2-core PCFs were optimized using numerical modeling for broadband supercontinuum (SC) generation. The first fiber structure with a lattice constant 1.5 µm and filling factor 0.4 has all-normal dispersion profile. The SC with a broadened spectral bandwidth from 0.64 to 1.70 µm is generated by pump pulses centered at a wavelength of 1.03 µm, 120 fs duration, and energy of 1.5 nJ. The second proposed structure—with lattice constant 1.5 µm and filling factor 0.65—has anomalous dispersion for wavelengths longer than 1.03 µm. We obtained high coherence of the SC pulses in the anomalous dispersion range over wavelengths of 0.7–2.4 µm with the same pump pulse as the first fiber and with input energy of 0.09 nJ. These fibers would be interesting candidates for all-fiber SC sources operating with low-energy pump lasers as cost-effective alternatives to glass core fibers.