A Programmable Fiber Mode Excitation and Coupling Method

Abstract

The invention discloses a programmable optical fiber mode stimulation and coupling method, and belongs to the field of optical communication. The programmable optical fiber mode stimulation and coupling method comprises the steps that (1) a light beam given out by a first single-mode optical fiber passes through a first collimation lens; (2) the light beam is divided into polarized light in the horizontal direction and polarized light in the perpendicular direction through a polarization beam splitter, the polarized light in the horizontal direction and polarized light in the perpendicular direction pass through a Faraday activizer, a half-wave plate and silicon-based liquid crystal to be stimulated to form high-order mode light beams in sequence; (3) the high-order mode light beams are respectively reflected to be horizontally input into the polarization beam splitter, beam combination is carried out, and a combined light beam of a high-order mode is output; (4) the combined light beam is input into a beam combiner in the horizontal direction, a light beam given out by a second single-mode optical fiber passes through a second collimation lens, and is input into the beam combiner in the perpendicular direction, and the light beam and the combined light beam which is input into the beam combiner, is input into the beam combiner in the horizontal direction and is of the high-order mode are together output from the beam combiner, and enter a few-mode optical fiber after being coupled through a focusing lens. Due to the facts that phase modulation is carried out on a light field through the silicon-based liquid crystal, and the voltage of each pixel of the silicon-based liquid crystal can be controlled through programming, high-accuracy selective stimulation of any high-order mode can be achieved, and meanwhile the function of polarization multiplexing and the function of mode multiplexing can be achieved.

Description

technical field [0001] The invention relates to the optical fiber mode selective excitation and coupling technology of the mode multiplexing system in the field of optical communication, in particular to a method for optical fiber mode selective excitation and coupling of multiple modes to the same few-mode optical fiber, which is mainly used for selectively exciting out advanced mode , and achieve low insertion loss coupling of multiple modes to the same few-mode fiber. Background technique [0002] Compared with the traditional optical fiber communication multiplexing technology, the mode multiplexing technology utilizes the spatial dimension of the optical field in the optical fiber, and uses multiple modes to transmit different information respectively, so as to achieve the purpose of improving the capacity of the optical fiber communication system; at the same time, due to the increased The effective area of ​​the fiber core reduces the damage to the optical signal ca...

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Problems solved by technology

[0003] Existing excitation schemes for fiber multiplexing include mode excitation based on long-period fiber gratings, mode excitation based on eccentric injection, etc. The writing of gratings is complex, greatly affected by temperature, and the dynamic range of working wavelength is very narrow, which is always limited Due to the accuracy, flexibility, working wavelength range and achievability of mode-selective excitation, it is not applicable to the combination of wavelength division multiplexing and mode division multiplexing

[0004] The existing multi-mode fiber to few-mode fiber mode coupling scheme adopts an all-fiber structure, but the insertion loss is large, the inter-mode interference and inter-mode crosstalk are large, and it is not suitable for exciting modes with complex mode field distributions, nor is it suitable for In the mode where the mode field distribution is circular, such as model

[0005] The existing mode excitation and coupling scheme based on multimode interference (MMI) is to realize the mode excitation by using the multimode interference generated by the connection of single-mode fiber, multimode fiber and single-mode fiber. The problem of this scheme is that the The modes that can be excited can only be some low-order modes, and are limited by the working wavelength. At the same time, the accuracy of the excited modes is affected by environmental factors, so the practicability is not strong

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