A third-order oam fiber with ultra-low attenuation, low crosstalk and weak coupling

Abstract

The invention relates to an ultra-low attenuation low crosstalk weak coupling three-order OAM optical fiber, comprising core layers and a cladding layer, characterized in that the number of the core layers is three, the delta 1 of the first core layer is -0.7% to -0.2%, R1 is 3.5 [mu]m-7 [mu]m, the delta 2 of the second core layer is 0.0% to 0.5%, R2 is 5.5 [mu]m-9 [mu]m, the delta 3 of the thirdcore layer is -0.6% to 0.1%, R3 is 7.5 [mu]m-11.5 [mu]m, and the delta 2 > the delta 3 > the delta 1, 3 [mu]m <= R3-R1 <= 6 [mu]m, the core layers are covered with the cladding layer, the cladding layer is composed of a subsidence cladding layer or two cladding layers of a subsidence cladding layer and a pure silica glass cladding layer, the subsidence cladding layer is a cladding layer closely surrounding the core layers, and the delta 4 is -0.9% to -0.6%, and R4 is 38 [mu]m-62.5 [mu]m. The invention supports up to three-order OAM modes in the 1550nm communication band, has larger effective refractive index difference and lower crosstalk between non-degenerate OAM modes of different orders, and has smaller effective refractive index difference and lower DGD between degenerate modes of thesame order.

Description

technical field [0001] The invention relates to an ultra-low attenuation, low crosstalk and weak coupling third-order OAM (orbital angular momentum) optical fiber used in an optical communication system, belonging to the technical field of optical fiber communication. Background technique [0002] Single-mode optical fibers are widely used in optical fiber communication networks due to their advantages such as fast transmission rate, large information carrying capacity, and long transmission distance. In traditional optical transmission networks, technologies such as time division multiplexing, wavelength division multiplexing, polarization multiplexing, and phase quadrature modulation have been fully applied in optical communication systems to increase the transmission capacity of a single fiber. In recent years, with the increasing demand for capacity of communication, video, big data and other services, the network bandwidth has expanded rapidly, and the capacity of optic...

AI Technical Summary

Problems solved by technology

Since MIMO processing technology needs to use expensive and complex instruments and equipment, and its complexity is proportional to the square of the number of modes supported in the fiber, if the number of modes in the fiber is large, the demodulation system will become quite complicated and Expensive, which severely limits the increase in the number of modes in the fiber, limits the increase in the capacity of a single fiber, and makes it hopeless for large-scale commercial use

Moreover, the attenuation of this kind of OAM fiber is relatively large at present, and the attenuation of the optical signal in the fiber is fast, which cannot meet the requirements of long-distance non-relay transmission, which also limits the application of this fiber in ultra-long-distance transmission.

Chinese patent CN105242347B proposes a parabolic OAM fiber, which has a small effective refractive index difference and large crosstalk between OAM modes in the fiber. In fact, although this parabolic multimode fiber can support high-order OAM modes , but the simultaneous existence of radial high-order modes makes the multiplexing of high-order OAM modes almost impossible

Chinese patents CN104003614B and CN108680990A respectively propose a ring-core OAM optical fiber. There is a large effective refractive index difference and small crosstalk between the OAM modes in the optical fiber, but the loss of the optical fiber is relatively large, reaching 2.0dB / km, respectively. 1.8dB / km

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