High non-linear single-polarization single-mode photon crystal optical fiber

Abstract

The invention discloses a single-polarization single-mode photonic crystal fiber with high nonlinearity. The cross section of the photonic crystal fiber comprises a fiber core and a cladding. The-cladding is a peripheral region which is the same as the normal photonic crystal fiber and is formed by evenly distributed air holes (2) with the same structure. The fiber core is composed of a substrate material (1) which is arranged on the center of the optical fiber end face as well as four high-ellipticity air holes (3) which are closely arranged, not mutually overlapped and in rectangular distribution. In the photonic crystal fiber, a cut off characteristic of two polarization modes of a basic mode can be adjusted by finely adjusting distance between centers of air holes, which causes one of the polarization modes to be cut off in the applied waveband, thus realizing the wide-bandwidth single polarization transmission. Meanwhile, the air holes (3) suppress the generation of high order mode, which allows the cladding to use a higher air filling rate on the premise of not changing the single-mode transmission characteristic of the optical fiber, therefore the mode area and the confinement loss are reduced. The single-polarization single-mode photonic crystal fiber with the high nonlinearity solves the problem that the high nonlinearity, low confinement loss and wide band single-polarization single-mode characteristic can not be realized at the same time in the existing photonic crystal fiber technology.

Description

Technical field [0001] The invention relates to a photonic crystal waveguide structure, in particular to a highly nonlinear single-polarization single-mode photonic crystal fiber. Background technique [0002] Photonic crystal fiber is also called holey fiber or microstructure fiber. On the fiber end face, many regularly arranged air holes on the order of wavelength extend axially in the base material, and an air hole is missing in the center of the fiber, replaced by a solid fiber base material, or inserted with a high refractive index. Other materials other than the base material form the light-guiding core, while the peripheral air holes are uniformly arranged in the base material to form a cladding, and the light field is basically limited to the high refractive index area in the center. The principle of reflection guides light, so it is also called total internal reflection photonic crystal fiber. By adjusting the size of air holes in the cladding, the size of the hol...

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Problems solved by technology

[0008] The purpose of the present invention is to solve the problem that the current single-polarization single-mode photonic crystal fiber with asymmetric cladding structure cannot simultaneously take into account the single-polarization single-mode transmission characteristics, small mode field area and low limit loss characteristics, and provide a simple structure Highly nonlinear single-polarization single-mode photonic crystal fiber that is easy to fabricate

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