Bending non-sensitive fibre optical with moderate modulus filed diameter

Abstract

A monomode optical fiber with suitable mode-field diameters, whcih is not sensitive to bending, is available for double windows of 1310nm and 1550nm wavelengths. It consists of three sub-layered cores and three sub-claddings with different refraction index profiles. The third layer of the sub-claddings is of pure silicon dioxide glass. It is suitable for distribution in rooms.

Description

technical field [0001] The invention relates to an optical fiber for access network and FTTH, especially a bending-insensitive single-mode optical fiber with a waveguide structure which has excellent bending performance and is suitable for being stored in a junction box or a closed container. Background technique [0002] At present, as FTTH begins to penetrate into residential users, the amount of optical fiber access network construction has increased significantly. Access network construction requires easier networking work and shorter time. This requires that the single-mode optical fiber suitable for the access network has the characteristics of small additional loss, high strength and suitable mode field diameter under a small bending radius, which is convenient for wiring construction and crimping, and can control the connection loss with the laid optical fiber at the same time. [0003] Due to the large mode field diameter (MFD) of conventional G.652 single-mode fib...

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Problems solved by technology

[0003] Due to the large mode field diameter (MFD) of conventional G.652 single-mode fiber, the general MAC value (that is, the mode field diameter divided by the cut-off wavelength) is in the range of 6-8, resulting in excessive macrobending loss, which is not suitable for small diameters (such as Curl with a bending diameter of 30mm), which brings inconvenience to the construction work of the access network

[0004] The G.655 single-mode fiber suitable for long distance, high capacity and high transmission rate focuses on the design of the optical fiber refractive index profile structure between the effective area of ​​the fiber and the dispersion characteristics in the C-band (or plus the L-band, or plus S-band, or the balance of S-band and L-band), generally speaking, there are two design ideas for this kind of fiber: one is that the fiber has a large effective area, and the dispersion characteristics are often not optimized enough; the second The first is that this kind of fiber has small dispersion and flat dispersion, but the effective area is not large enough

For G.655 single-mode optical fiber products with the second design idea, for example, those involved in Chinese patents CN1487318A, CN1424599A, CN1484051A, CN1514262A, CN1415983A and CN1479121A, the macrobend loss at 1550nm wavelength is small, and the mode field diameter is also suitable. However, due to the cut-off wavelength ≥ 1330nm, it cannot be used for single-mode transmission with a wavelength of 1310nm

[0005] As a dispersion compensating optical fiber product matched with G.655 single-mode optical fiber, for example, the Chinese patent CN1313954A involves, although it can also meet the small additional loss and suitable mode field of the single-mode optical fiber used in the access network under the small bending radius Two characteristics of diameter, but because the absolute value of dispersion is too large, it cannot be used as an optical transmission fiber for dual windows of 1310nm wavelength and 1550nm wavelength

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