Method of drawing a twisted optical fiber

• US 6,347,537 B1
• Filed: 02/22/2000
• Issued: 02/19/2002
• Est. Priority Date: 03/01/1995
• Status: Expired due to Term

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Amemiya, Koji, Ishiguro, Yoichi, Takagi, Masahiro, Onishi, Masashi
• Primary Examiner(s): HOFFMANN, JOHN M
• Application Number:
  US09/510,237
• Time in Patent Office: 728 Days
• Field of Search: 654/02, 655/04
• US Class Current: 65/402
• CPC Class Codes: C03B 2203/06 Axial perturbations, e.g. twist, by torsion, undulating, crimped
• CPC Class Codes: C03B 2203/19 Alternating positive/negative spins or twists
• CPC Class Codes: C03B 2203/24 Single mode [SM or monomode]
• CPC Class Codes: C03B 2203/36 Dispersion modified fibres, e.g. wavelength or polarisation shifted, flattened or compensating fibres (DSF, DFF, DCF)
• CPC Class Codes: C03B 2205/06 Rotating the fibre fibre about its longitudinal axis
• CPC Class Codes: C03B 37/027 Fibres composed of different sorts of glass, e.g. glass optical fibresC03B37/0253, C03B37/028 take precedence
• CPC Class Codes: C03B 37/02745 Fibres having rotational spin around the central longitudinal axis, e.g. alternating +/- spin to reduce polarisation mode dispersion
• CPC Class Codes: C03B 37/03 Drawing means, e.g. drawing drums ; Traction or tensioning devices
• CPC Class Codes: C03B 37/032 for glass optical fibres
• CPC Class Codes: C03C 25/12 General methods of coating; Devices therefor
• CPC Class Codes: G02B 6/02285 Characterised by the polarisation mode dispersion [PMD] properties, e.g. for minimising PMD fabrication methods for minimising PMD C03B37/02745
• CPC Class Codes: G02B 6/105 having optical polarisation effects

Abstract

An optical fiber is rolled by a swing motion of a swing guide roller in order to impart a predetermined twist to it effectively, and its polarization dispersion is suppressed equivalently as in a perfectly circular concentric optical fiber. A method of manufacturing such an optical fiber is also provided. As a swing guide roller swings, the optical fiber is rolled on its roller surface, so that a clockwise twist and a counterclockwise twist are imparted to the optical fiber alternately. At this time, the optical fiber is fitted in a V-shaped narrow groove formed at the central portion of the roller surface of a next-stage first stationary guide roller provided just beside the swing guide roller. Rolling of the optical fiber on the roller surface of the first stationary guide roller is suppressed, thereby helping smooth rolling of the optical fiber on the roller surface of the swing guide roller. As a result, a twist can be imparted to the optical fiber highly efficiently in accordance with the swing speed of the swing guide roller.

Claims

1. An optical fiber drawing method for reducing polarization characteristic of an optical fiber, comprising:

drawing said optical fiber from an optical fiber preform;

coating said optical fiber with a predetermined coating material; and

guiding said optical fiber coated with said predetermined coating material with a first guide roller that swings periodically, and rolling said optical fiber on a roller surface of said first guide roller in accordance with the swing of said first guide roller; and

guiding said optical fiber that has passed through said first guide roller with a second guide roller provided to a next stage of said first guide roller and having a fixed rotating shaft and suppressing said optical fiber from rolling on a roller surface of said second guide roller with an optical fiber rolling suppression portion provided to said second guide roller,

wherein the swing of said first guide roller is such that the maximum clockwise angle and the maximum counterclockwise angle of said first guide roller are equal, such that a period of the clockwise swing which is the time from the beginning to the end of the clockwise swing of said first guide roller and a period of the counterclockwise swing which is the time from the beginning to the end of the counterclockwise swing of said first guide roller are equal, and such that a swing direction of said first guide roller is reversed smoothly without stopping when the swing angle of said first guide roller becomes maximum,

wherein an optical fiber responsive motion suppressing means is provided to a preceding stage of said first guide roller, said means comprises at least one pair of responsive motion suppressing rollers which are provided above said first guide roller at a predetermined distance, said responsive motion suppressing rollers opposing each other at a predetermined gap through which said optical fiber is passed.

2. A method according to claim 1, wherein a width of said roller surface of said first guide roller on which said optical fiber can be rolled, is not less than 3 mm.

3. A method according to claim 1, wherein said first guide roller has flanges at both sides of said roller surface, and

wherein said optical fiber does not come into contact with said flanges when the swing angle of said first guide roller becomes maximum.