Supercontinuum Generation in Suspended-Core Heavy-Metal Oxide Glass Photonic Crystal Fibers

In this paper we investigate supercontinuum (SC) generation in several suspended-core soft-glass photonic crystal fibers (PCFs) pumped by an optical parametric oscillator (OPO) tunable around 1550 nm. The fibers were drawn from leadbismuth- gallium-cadmium-oxide glass (PBG81) featuring a wide transmission window from 0.5 mu m till 2.7 mu m and a high nonlinear refractive index up to 43x10(-20) m(2)/W. They have been specifically designed with a microscale suspended hexagonal core for efficient pumping around 1550 nm. This microstructure geometry also prevents from glass recrystallization and provides higher mechanical durability. We experimentally demonstrate two SC spectra spanning from 1.07 mu m to 2.31 mu m and 0.89 mu m to 2.46 mu m by pumping two PCFs in both normal and anomalous dispersion regimes at 1550 nm and 1580 nm, respectively. We further show a number of nonlinear phenomena such as spectral broadening due to self-phase modulation, soliton generation, and Raman soliton self-frequency shift in the fiber at the pumping wavelengths. We also numerically simulate the group velocity dispersion curves for these fibers from their scanning electron microscope (SEM) images.