Ge20Sb15Se65硫系玻璃光子晶体光纤的中红外色散特性

硫系玻璃与石英玻璃相比具有高折射率(2.0~3.5)、低声子能量 (<350 cm^-1)、优良的中远红外透过性能(可至25 μm)等特性.本文制备了一种在中红外具有优良透过特性的无As环保型Ge₂₀Sb₁₅Se₆₅硫系玻璃材料,以此为基质材料设计了一种三层空气孔结构光子晶体光纤,利用多极法对光纤的中红外色散特性进行了数值模拟,系统研究了结构参量孔径d、孔间距Λ 以及d/Λ 对其色散特性的影响.分析表明:通过改变包层空气孔直径d或空气孔间距Λ,可灵活的调节光子晶体光纤的零色散波长向短波或长波方向移动.通过优化结构参量发现,当Λ=3 μm,d/Λ=0.35 附近变化时,可获得3~5 μm色散平坦,且色散值小于5 ps·nm^-1·km^-1的光子晶体光纤.

Dispersion Properties of Ge20Sb15Se65 Chalcogenide Glass Photonic Crystal Fiber for Mid-IR Region

Compared with silica glass, chalcogenide glass possesses some unique advantages, such as high refractive index (2.0~3.5), low phonon energy (lower than 350 cm^-1), and large infrared transmission window (up to 25 μm). In this paper, a kind of environmental protected Ge₂₀Sb₁₅Se₆₅ chalcogenide glass was prepared, which showed good transmission in IR range. Based on this glass, a photonic crystal fiber with three rings air holes was designed. Multi-pole method was employed to study the dispersion properties of the designed photonic crystal fiber. The relationship between fiber structure parameters(the air diameter d, period Λ and the ratio d/Λ)and dispersion properties was presented. The simulation results showed that the zero dispersion point of photonic crystal fiber can be flexibility tuned to short or long wavelength region by control the fiber structure parameters. Finally, by optimizing the sturcure parameters, the dispersion flat photonic crystal fiber through of 3~5 μm was obtained, with the dispersion value less than 5 ps·nm^-1·km^-1.