Few-mode fiber with relatively low different group delay (DGD)

Abstract

The invention relates to a few-mode fiber with relatively low different group delay (DGD). The few-mode fiber comprises a core layer and claddings, and is characterized in that the relative refractive index difference delta 1 of the core layer is 0.24% to 0.36%; the radius R1 of the core layer is 9-12 micrometers; the claddings coating the core layer comprise an inner cladding, a sunken cladding and an outer cladding from inside to outside; the relative refractive index difference delta 2 of the inner cladding is -0.02% to 0.02%; the radius R2 of the inner cladding is 13.6-18 micrometers; the sunken cladding is divided into a first sunken cladding and a second sunken cladding; the radius R3 of the first sunken cladding is 16-30 micrometers; the difference between R3 and R2 is larger than or equal to 2 micrometers; the relative refractive index difference of the first sunken cladding is alpha-type refractive index distribution gradually reduced from delta 2 at R2 to delta 3 at R3; delta 3 is -0.8% to -0.4%; the relative refractive index difference of the second sunken cladding is delta 3; the radius R4 is 18.6-30 micrometers; R4 is larger than or equal to R3; the quotient of the difference between R3 and R2 divided by the difference between R4 and R2 is larger than or equal to 0.5 and smaller than or equal to 1; the outer cladding is a pure quartz glass layer. The few-mode fiber has lower DGD and relatively high MFD, and keeps relatively good anti-bending performance.

Description

technical field [0001] The invention relates to a few-mode optical fiber used in an optical fiber communication system, the optical fiber supports four modes in the 1550nm communication band, has a lower differential mode group delay (DGD) and a larger mode field diameter (MFD), It belongs 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 recent years, with the increasing demand for capacity of communication and big data services, the network bandwidth has rapidly expanded, and the capacity of optical transmission networks is gradually approaching the Shannon limit of a single optical fiber: 100Tb / s. Space-division multiplexing and mode-division multiplexing technologies can break the traditional Shannon limit and achieve higher ban...

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Problems solved by technology

However, while these two methods increase the effective area, they will also have a greater impact on other optical performance parameters of the fiber....

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