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Optical fiber and method of manufacturing the same

a technology of optical fiber and manufacturing method, applied in the field of optical fiber, can solve the problems of double refraction, uncircularized portion, etc., and achieve the effect of preventing deterioration of good polarization mode dispersion characteristic, and suppressing continuity in longitudinal direction

Inactive Publication Date: 2008-06-19
SUMITOMO ELECTRIC IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0004]Accordingly, an object of the present invention is to provide an optical fiber which can suppress deterioration of a polarization mode dispersion characteristic thereof to acquire a good polarization mode dispersion characteristic thereof.
[0017]According to the optical fiber of the present invention suppresses continuity in the longitudinal direction of a vector of a stress applied to the optical fiber by decentering the covering layer with respect to the glass portion and making the covering layer uncircular, whereby deterioration of the polarization mode dispersion characteristic can be prevented, and a good polarization mode dispersion characteristic in the longitudinal direction of the optical fiber can be acquired as a whole. Moreover, according to the method of manufacturing an optical fiber of the present invention, the foregoing optical fiber can be suitably manufactured.

Problems solved by technology

However, though the cross section shape of the refractive index distribution in the core portion of the optical fiber can be made close to the perfect circle, force is applied to the optical fiber from the outside, and a stress originating from this external force is generated, thus causing double refraction.
As a result, there is a problem that the light propagation portion is uncircularized and the polarization mode dispersion characteristic is deteriorated.

Method used

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  • Optical fiber and method of manufacturing the same
  • Optical fiber and method of manufacturing the same
  • Optical fiber and method of manufacturing the same

Examples

Experimental program
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Effect test

first embodiment

[0027]The optical fiber 1 of this embodiment comprises a glass portion 2 including a core 2a having a high refractive index and a cladding 2b having a low refractive index, which is formed around the core 2a, and a covering layer 3, which is composed of an internal covering layer 3a having a low Young's modulus and an external covering layer 3b having a high Young's modulus. An external diameter of the glass portion 2 is 125 μm, an external diameter of the internal covering layer 3a ranges from 170 to 200 μm, and an external diameter of the external covering layer 3b ranges from 235 to 265 μm. Any of the internal and external covering layers 3a and 3b is a resin covering layer using ultra violet-curing resin. The glass portion 2, the internal covering layer 3a and the external covering layer 3b assume a circular shape on a section (transverse plane) perpendicular to the longitudinal direction (extending direction) of the optical fiber 1, the circular shape having an out-of-roundness...

second embodiment

[0032]In this embodiment, as shown in FIGS. 3A to 3E, the center of the glass portion 2 and the center of the internal covering layer 3a are approximately coincident with each other as the center O1. On the contrary, the center O2 of the external covering layer 3b is decentered from the center O1. The decenter direction (arrow direction in FIGS. 3A to 3E) is changed in the longitudinal direction of the optical fiber 1. Particularly, in this embodiment, the decenter direction is rotated in a certain direction (clockwise in FIGS. 3A to 3E) along the longitudinal direction (direction of the arrow L in FIG. 1) of the optical fiber 1.

[0033]Since the glass portion 2 and the external covering layer 3b are decentered from each other in the optical fiber 1 of this embodiment, the continuity in the longitudinal direction of the stress vector applied to the optical fiber 1 is consequently controlled. Also with such a configuration, similarly to the foregoing first embodiment, deterioration of ...

third embodiment

[0037]In this embodiment, as shown in FIGS. 4A to 4E, the outer peripheral shape of the internal covering layer 3a in cross section (perpendicular to the longitudinal direction of the optical fiber 1), that is, the shape of the boundary surface between the internal covering layer 3a and the external covering layer 3b, is uncircularized. “Uncircularize” means that the shape is intentionally made not to be a perfect circle. Specifically, the out-of-roundness of the outer periphery of the internal covering layer 3a in cross section is intentionally made to be large on the cross section perpendicular to the longitudinal direction of the optical fiber 1. Herein, the out-of-roundness is defined as a difference between the maximum diameter of an inscribed circle and the minimum diameter of a circumscribed circle. In this embodiment, the outer peripheral shape of the internal covering layer 3a in cross section is made to be elliptical as one mode of uncircularize.

[0038]The outer peripheral ...

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Abstract

An optical fiber 1 comprising a glass portion 2 having a core 2a and a cladding 2b, and one or more covering layers 3 formed around the glass portion 2, in which an arrangement form of the covering layer 3 with respect to the glass portion 2 in cross section perpendicular to a longitudinal direction thereof is changed continuously in the longitudinal direction thereof.

Description

TECHNICAL FIELD[0001]The present invention relates to an optical fiber capable of compensating polarization mode dispersion effectively, and a method of manufacturing the same.BACKGROUND OF THE INVENTION[0002]In recent years, as a wavelength division multiplexing (WDM) transmission and an optical amplification technology progress, while an effective core area (Aeff) of an optical fiber has been scaled up, a more reduction of a polarization mode dispersion (PMD) characteristic has been desired. The polarization mode dispersion characteristic is caused by a transmission speed difference of optical signals between polarization waves perpendicular to each other, and depends on the symmetry of a refractive index distribution of the optical fiber. To be more specific, as the cross section shape of the refractive index distribution in a core portion (light propagation portion), through which a major part of light propagates, is closer to a perfect circle, the PMD characteristic in terms of...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C03C25/26C03C25/10C03C25/18G02B6/10
CPCC03C25/1065G02B6/105G02B6/0228C03C25/18
Inventor SHIMODA, KOJIKUBO, YUJISHIMIZU, MAKOTO
Owner SUMITOMO ELECTRIC IND LTD
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