A High Birefringence Large Nonlinear Photonic Crystal Fiber

Abstract

The invention provides a high birefringence and large nonlinear photonic crystal optical fiber. The optical fiber is composed of a first elliptical air hole and a second elliptical air hole. The hexagonal lattice elliptical air hole array structure works in the mid-infrared range of 3 μm to 5 μm. High birefringence large nonlinear photonic crystal fiber, including core and cladding on the fiber background material, the cladding is composed of two kinds of first elliptical air holes and second elliptical air holes with the same long axis and different short axis The six-layer hexagonal lattice elliptical air hole array is formed, the second elliptical air hole array is arranged along the y-axis direction, the first elliptical air hole array is arranged along the x-axis direction, and the center of the optical fiber background material The solid area of ​​the position is the fiber core. The fiber obtains a high birefringence of 0.1177 in the wavelength range of 3 μm to 5 μm, and the corresponding beat length is 42.4 μm. The nonlinear coefficient of the fiber in the x and y polarization directions is 38390w ‑1 km ‑1 and 49760w ‑1 km ‑1 .

Description

technical field [0001] The invention relates to the technical field of mid-infrared optical fiber communication and optical fiber sensing, in particular to a high birefringence and large nonlinear photonic crystal fiber working in the mid-infrared range of 3 μm to 5 μm. Background technique [0002] The fundamental mode transmitted in a single-mode fiber is composed of two degenerate orthogonal polarization modes. Under ideal conditions (the fiber is cylindrically symmetric and unstressed), the two orthogonal polarization modes are fully coupled . For the actual optical fiber, due to the influence of gravity and the existence of internal residual stress during the drawing process, the shape of the fiber core changes randomly along the length of the fiber, and the fiber no longer exhibits ideal cylindrical symmetry. As a result, the degenerate mode is destroyed. The resulting two orthogonal polarization states have different propagation constants, which in turn causes a diff...

AI Technical Summary

Problems solved by technology

However, the working wavelength (less than 3 μm) of the traditional photonic crystal fiber made of quartz material limits its application in the mid-infrared and far-infrared, and the nonlinear coefficient of the quartz material is small, making it difficult to realize the high nonlinear device. Miniaturization and Integration

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