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Method for compensating modal dispersion in multimode optical fiber transmission path

A multi-mode fiber, modal dispersion technology, applied in the direction of optical waveguide light guide, etc., can solve the problems of complex calculation, difficulty, long time and so on

Inactive Publication Date: 2006-03-08
THE FUJIKURA CABLE WORKS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0021] However, this method requires complex calculations and is not easy to program for electronic calculations
Moreover, the calculation for simulation takes a long time, for example, it cannot be used in the field where optical transmission lines are laid, etc.

Method used

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  • Method for compensating modal dispersion in multimode optical fiber transmission path
  • Method for compensating modal dispersion in multimode optical fiber transmission path
  • Method for compensating modal dispersion in multimode optical fiber transmission path

Examples

Experimental program
Comparison scheme
Effect test

specific example 2-1

[0232] Figure 31 The refractive index distributions of the optical fiber to be compensated and the modal dispersion compensating optical fiber in Specific Example 2-1, and the refractive index distribution that can obtain the maximum frequency band in the wavelength of the signal light used are shown.

[0233] The fiber to be compensated is the refractive index n at a distance r from the center of its core target (r) is formed by approximate calculation using the following formula (9).

[0234] Among them, n(r) represents the refractive index at a distance r from the center of the fiber core, n 1Indicates the refractive index at the center of the fiber core, Δ 1 Indicates the specific refractive index difference between the center of the core and the cladding, a indicates the radius of the core, and α indicates the power of the refractive index distribution.

[0235] n ( r ) = ...

specific example 2-2

[0264] Using the optical fiber to be compensated and the modal dispersion compensating optical fiber having the refractive index distribution powers shown in Table 2, an optical transmission line was formed in the same manner as in Specific Example 2-1. When the wavelength of the signal light is 0.85 μm, the refractive index distribution power α of the refractive index distribution in the maximum frequency band can be obtained opt is 2.04.

[0265]

specific example

signal light

the wavelength of

(μm)

Compensated fiber

Refractive index

distribution power

alpha target

Modal Dispersion Compensation

Compensation fiber fold

Emissivity distribution constant

number k

Modal Dispersion Compensation

length of compensating fiber

L comp (km)

2-2

0.85

1.90

2

0.162

2-3

0.85

2.00

10

0.11

2-4

0.85

2.03

20

...

specific example 2-3

[0272] Figure 37 The frequency band of the OFL of the optical transmission line using the compensated optical fiber in Example 2-3 is calculated by simulation, and the length L of the optical fiber is compensated by the modal dispersion comp to draw the graph. The difference from the specific example 2-1 is that the refractive index distribution power of the compensated fiber α target is 2.00.

[0273] It can be seen that despite the expression Δ comp (r) The larger the constant k in the formula (8), the smaller the maximum value of the frequency band tends to be. However, when the constant k is 10 or less, the maximum value of the frequency band does not tend to decrease significantly, but remains almost constant.

[0274] Therefore, in the case of compensating the modal dispersion of the compensated optical fiber in specific example 2-3, Δ with constant k of 10 in formula (8) is adopted comp For the modal dispersion compensating fiber of (r), the length L of the modal d...

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Abstract

In an optical transmission line consisting of a multimode optical fiber, the mode dispersion of the optical transmission line is reduced in order to permit a wide-band optical signal to be transmitted at high speed, over a long distance and at low costs. When a plurality of multimode optical fibers are connected together to form a transmission line for the purpose of reducing a mode dispersion, length ratios between the respective multimode optical fibers that can maximize the band of this optical transmission are determined, and they are connected together at the length ratios. In addition, a multimode optical fiber having a specific refractive index profile is used as a mode dispersion compensating fiber. Also, a compensated fiber and a compensating fiber each having a specific length are connected together.

Description

technical field [0001] The present invention relates to a method for compensating modal dispersion in an optical transmission line constructed with multimode optical fibers, which can reduce the modal dispersion of the optical transmission line and obtain a wide transmission frequency band. Background technique [0002] In general, in FA (factory automation) and OA (office automation), etc., in LAN (local area network) that connects computers and related equipment through optical transmission lines, in this optical transmission line, it is widely used to realize the light receiving surface. A multimode optical fiber that can be easily combined with light-emitting and light-receiving devices with a larger diameter. [0003] In this multimode optical fiber, a graded-index optical fiber (hereinafter referred to as GI optical fiber) is an optical fiber in which the refractive index distribution of the core is formed such that the refractive index gradually decreases as the radiu...

Claims

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Application Information

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IPC IPC(8): G02B6/10
Inventor 官宁羽生伸治竹永胜宏姬野邦治原田光一
Owner THE FUJIKURA CABLE WORKS LTD
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