Coaxial double-waveguide optical fiber capable of generating vortex light and toroidal field, and preparation method of coaxial double-waveguide optical fiber

Abstract

The invention provides a coaxial double-waveguide optical fiber capable of generating vortex light and a toroidal field, and a preparation method of the coaxial double-waveguide optical fiber. The optical fiber comprises a cladding layer 1, a central round less-mode fiber core 2, a spiral fiber core 3 and a toroidal fiber core 4, wherein the less-mode fiber core 2 is located in the center of the cladding layer 1; the spiral fiber core 3 surrounds the less-mode fiber core 2; and the toroidal fiber core 4 is overlapped with the axis of the less-mode fiber core 2. On one hand, due to periodic perturbation of the spiral fiber core 3, a low-order linear polarization mode (such as an LP11 mode 5) of transmission of the less-mode fiber core 2 can be converted into a high-order phase vortex mode,and a vortex light beam 6 is generated at an optical fiber end. On the other hand, when a Gaussian light field 7 (or the toroidal light field) is input to the toroidal fiber core 4 in a coupled manner, a toroidal transmission mode can be excited in the toroidal fiber core 4, and finally the toroidal light field 8 is output at the optical fiber end. The optical fiber can be prepared through a direct hot melting, rotating and wiredrawing method or a wiredrawing, hot melting and rotating method. The optical fiber can be applied to the fields of vortex light beam and toroidal light beam generationand transmission, optical communication, optical sensing, optical manipulation and the like.

Description

(1) Technical field [0001] The invention relates to a coaxial double waveguide fiber capable of generating vortex light and ring field and its preparation method, which can be used for generation and transmission of vortex beam and ring beam, optical communication, light sensing, light manipulation, etc., and belongs to optical fiber technology field. (2) Background technology [0002] As we all know, electromagnetic waves transmit not only energy but also momentum, which is a unique property of translational motion of all objects. When the momentum of electromagnetic waves is absorbed or scattered by other objects, "radiation pressure" will be formed, thereby forming mechanical pressure on the object . Likewise, light waves have angular momentum, a property of all rotational motion. The angular momentum of light wave can be decomposed into spin angular momentum and orbital angular momentum on the optical axis. What is special is that the light wave front with optical orb...

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Problems solved by technology

Although the structure of the vortex beam generator is extremely simple, it is very difficult to fabricate such an optical fiber

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