Toward mid-IR supercontinuum generation in bismuth-lead-galate glass based photonic crystal fibers

Abstract

In this paper we report a two octave spanning supercontinuum generation in the range 750-3000 nm with a newly developed photonic crystal fiber. The fibre is fabricated using an in-house synthesized lead-bismuth-galate glass PBG08 with optimised rheological and transmission properties in the range 500-4800 nm. The photonic cladding consists of 8 rings of air holes with a fibre core diameter of 3 μm and a lattice constant of 2.2 μm. The dispersion characteristic is determined mainly by the material dispersion and the first ring of holes in the cladding with a filling factor of 0.68. The filling factor of the remaining 7 rings is 0.45 which allows single mode performance of the fibre in the infrared range. The fibre has a zero dispersion wavelength of 1490 nm which allows the use of 1550 nm wavelength as an efficient pump in the anomalous dispersion regime. The 2 cm long sample of photonic crystal fiber is pumped in the femtosecond regime with a pulse energy of 10 nJ at a wavelength of 1550 nm. A flatness of 5 dB is observed in the spectral range 950-2500 nm.