Ultralow-attenuation low-crosstalk weakly-coupled five-order OAM optical fiber

Abstract

The invention relates to an ultralow-attenuation low-crosstalk weakly-coupled five-order OAM optical fiber. The optical fiber comprises core layers and cladding layer, and is characterized in that thecore layers are three layers, and sequentially include a first core layer, a second core layer and a third core layer from inside to outside; delta 1 of the first core layer is -0.8w% to -0.4%, and R1 is 6-9 [mu]m; delta 2 of the second core layer is 0.0-0.55%, and R2 is 8.5-11. 5 [mu]m; delta 3 of the third core layer is -0.6% to 0.15%, and R3 is 10-13.5 [mu]m; delta 2 is larger than delta 3, delta 3 is larger than delta 1, and R3-R1 is larger than or equal to 3 [mu]m and less than or equal to 7 [mu]m; the cladding layer wraps the core layers; the cladding layer is composed of a sunken cladding layer, or is composed of two cladding layers including the sunken cladding layer and a pure silicon dioxide glass cladding layer; the sunken cladding layer is a cladding layer tightly surroundingthe core layers; and delta 4 is -0.9% to -0.6%, and R4 is 40-62.5 [mu]m. OAM modes of at most five orders is supported at a communication waveband of 1,550 nm; a relatively large effective refractiveindex difference and relatively low crosstalk exist between non-degenerate OAM modes of different orders; and a relatively small effective refractive index difference and a relatively low DGD exist between degenerate modes of the same order.

Description

technical field [0001] The invention relates to an ultra-low attenuation, low crosstalk and weak coupling fifth-order OAM (orbital angular momentum) optical fiber used in an optical fiber 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...

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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