Bandgaps of the Chalcogenide Glass Hollow-Core Photonic Crystal Fiber

Bandgaps of chalcogenide glass hollow-core photonic crystal fibers (GLS HC-PCFs) are analyzed by using the plane-wave expansion method. A mid-infrared laser can propagate in these low confinement loss fibers when the wavelength falls into the bandgaps. For enlarging the bandgap width, an improved GLS HC-PCF is put forward, the normalized frequency kΛ of the improved fiber is from 7.2 to 8.5 in its first bandgap. The improved GLS HC−PCF with pitch of 4.2 µm can transmit the lights with wavelengths ranging from 3.1 µm to 3.7 µm .