A High Birefringence and Low Confinement Loss Photonic Crystal Fiber

Abstract

A photonic crystal fiber with high birefringence and low confinement loss, including a core and a cladding, the core is located at the center of the fiber and is provided with an elliptical small air hole; the cladding is composed of an inner cladding and an outer cladding, wherein the core is surrounded by The inner cladding includes four symmetrical elliptical large air holes and two symmetrical circular air holes, and the outer cladding surrounding the inner cladding is provided with elliptical large air holes. The structure arranged according to the grid nodes is that every three phases The adjacent elliptical large air holes are arranged in an equilateral triangle structure on the optical fiber cross section. The advantages of the present invention are: the photonic crystal fiber has a novel structure, the photonic crystal fiber has double rotational symmetry by changing the configuration of the fiber structure, the orthogonal polarization mode is no longer degenerate, the birefringence is high, and the confinement loss is low; the photonic crystal fiber The birefringence of the crystal fiber is realized by changing the geometric size of each air hole, the influence of temperature and pressure is small, and the stability is good, so it is more suitable for practical applications.

Description

technical field [0001] The invention belongs to the field of optical fiber technology, in particular to a photonic crystal optical fiber with high birefringence and low limited loss. Background technique [0002] In a single-mode fiber, the fundamental mode is composed of two mutually orthogonal polarization modes, which have the same propagation constant and are degenerate with each other, so they can be regarded as a single polarization electric vector. However, the actual optical fiber has some imperfections in the process of production, cabling, laying, etc., and the internal refractive index distribution is also uneven due to the uneven internal stress. These factors will cause the refractive index of the fiber to be unequal in different directions, that is, there are differences in the propagation constants of the two orthogonal polarization modes, which destroy the mutual degeneracy of the fundamental modes, resulting in mode birefringence. The polarization-maintain...

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problem of low birefringence of the existing photonic crystal fiber, to provide a photonic crystal fiber with high birefringence and low confinement loss, which has a simple structure and is easy to manufacture. The structure of the fiber itself has double rotational symmetry, and can obtain Higher birefringence than existing birefringent photonic crystal fibers and very low confining loss

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