CN-115836195-B - Bending apparatus for measuring bending loss and bending test apparatus

CN115836195BCN 115836195 BCN115836195 BCN 115836195BCN-115836195-B

Abstract

The bending device (30) has at least 3 or more spindles (exemplified by a fixed spindle (55) and a movable spindle (65)), and bends the drawn optical fiber (F) by winding the optical fiber around the spindles. The diameter of the optical fiber is D, the radius of the mandrel is r, the direction in which the upstream-side tangential point (T1) at which the optical fiber comes into contact with the mandrel and the downstream-side tangential point (T2) at which the optical fiber comes out of contact with the mandrel are connected is the 1 st direction (illustrated in the horizontal direction), the interval between adjacent mandrels viewed in the 1 st direction is 2r+d, the direction orthogonal to the 1 st direction is the 2 nd direction (illustrated in the vertical direction), and the interval between adjacent mandrels viewed in the 2 nd direction is s. The angle θ between the 2 nd direction and the common internal tangent of the adjacent spindles observed at the center position of the optical fiber is 0 degrees or more and 45 degrees or less, satisfying expression 3.

Inventors

KAWAGUCHI YUKI
ZHENG ZHONGDA
TERAUCHI TOMOKO
Hatanaka tomoyoshi

Assignees

住友电气工业株式会社

Dates

Publication Date: 20260508
Application Date: 20210610
Priority Date: 20200612

Claims (6)

1. A bending device for measuring bending loss, comprising at least 3 spindles, wherein the optical fiber is wound around the spindles to impart bending to the optical fiber, The spindles are arranged so as to be offset from each other with a predetermined distance therebetween so as to face each other in a non-contact manner on the outer circumferences of the spindles adjacent in the longitudinal direction of the optical fibers, the diameter of the optical fibers is defined as D, the radius of the spindle is defined as r, the plane orthogonal to the rotation axis of the spindle is defined as 2 nd, the distance between the optical fiber wound around the spindle located at the center among the 3 spindles having the same diameter and arranged continuously in the longitudinal direction of the optical fibers and the upstream side where the spindle located at the center comes into contact with each other, the direction in which the optical fiber wound around the spindle located at the center comes into contact with the downstream side where the optical fiber wound around the spindle starts to separate from the spindle located at the center is defined as 1 st, the distance between the adjacent spindles observed in the 1 st is defined as 2r+d, the plane orthogonal to the rotation axis of the spindle is defined as s, the distance between the adjacent spindles observed in the 2 nd, the angle between the adjacent spindles observed in the 2 nd and the adjacent spindles observed in the 2 th direction is defined as s, and the angle between the adjacent spindles observed in the 2 th direction is equal to the tangent to the 0 th axis, and the angle between the adjacent spindles observed in the 2 th direction is equal to the 0 th axis [ 3] Wherein each of the adjacent spindles is a movable spindle and a fixed spindle which is not movable, the movable spindle being configured to be movable relative to the fixed spindle between a reference position where no bending is imparted to the optical fiber and an advanced position where bending is imparted to the optical fiber, The optical fiber is bent by moving a moving mandrel located on the downstream side as viewed in the longitudinal direction of the optical fiber among the plurality of moving mandrels, earlier than a moving mandrel located on the upstream side.
2. The bending apparatus for measuring bending loss according to claim 1, wherein, The bending imparting device has guide portions for ensuring a supply height of the optical fiber toward the spindle and a discharge height of the optical fiber separated from the spindle, respectively.
3. The bending apparatus for measuring bending loss according to claim 2, wherein, The guide portions are arranged side by side in a direction intersecting the longitudinal direction of the optical fiber.
4. A bending test apparatus comprising the bending apparatus for measuring bending loss according to any one of claims 1 to 3, The bending test device has a tension applying mechanism for applying tension to the optical fiber directed toward the mandrel.
5. The bending test device according to claim 4, wherein, The bending test device has at least a bending device located on an upstream side of the optical fiber as viewed in the longitudinal direction of the optical fiber, and a bending device located on a downstream side of the bending device on the downstream side of the bending device, wherein a mandrel of the bending device on the downstream side is formed to have a larger diameter than a mandrel of the bending device on the upstream side, The bending is imparted to the optical fiber by moving the spindle of the downstream bending imparting device in the 2 nd direction earlier than the spindle of the upstream bending imparting device.
6. The bending test device according to claim 4 or 5, wherein, The optical fiber bending device includes an arithmetic unit for obtaining bending loss based on the length of the optical fiber to which bending is applied.

Description

Bending apparatus for measuring bending loss and bending test apparatus Technical Field The present invention relates to a bending imparting device and a bending test device for measuring bending loss. The present application is based on japanese patent application No. 2020-102572, filed on 12 th month 6 of 2020, and claims priority, and the entire contents of the above japanese patent application are incorporated herein. Background Bending loss characteristics are one of the fundamental characteristics of an optical fiber. The international standard ITU-T (International Telecommunication Union-TelecommunicationStandardization sector) proposed g.652 describes the characteristics of a general single mode fiber (SMF: single Mode Fiber), and the international standard ITU-T (International Telecommunication Union-TelecommunicationStandardization sector) proposed g.657 describes the characteristics of a low-bending loss single mode fiber. The bending loss is obtained from the attenuation of light with respect to the bent optical fiber. For example, patent document 1 discloses a structure in which a plurality of side surfaces of different curvatures are provided on 1 cylinder to determine bending loss. Patent document 1 Japanese patent laid-open No. 1-203938 Disclosure of Invention The bending loss measuring apparatus for an optical fiber according to one aspect of the present invention includes at least 3 or more spindles which are arranged so as to be offset from each other at a predetermined interval so as to face each other in a noncontact manner on the outer periphery of a spindle adjacent in the longitudinal direction of the optical fiber by winding an extracted optical fiber around the spindles, wherein the diameter of the optical fiber is D, the radius of the spindle is r, and the interval between adjacent spindles observed in the 1 st direction is 2r, in a plane orthogonal to the rotation axis of the spindle, at which a tangent point of an optical fiber wound around a spindle located at the center among 3 spindles having the same diameter continuously arranged in the longitudinal direction of the optical fiber and an upstream side of the spindle located at the center are connected to each other, and at which an optical fiber wound around the spindle located at the center is connected to a downstream side of the spindle located at the center from the tangent point located at the center are connected to each other +D, wherein a direction orthogonal to the 1 st direction is defined as a2 nd direction on a plane orthogonal to the rotation axis of the spindle, an interval between adjacent spindles as viewed in the 2 nd direction is defined as s, and an angle θ between the 2 nd direction and a common internal tangent line of the adjacent spindles as viewed in the center position of the optical fiber is not less than 0 degrees and not more than 45 degrees. Wherein the angle θ satisfies the following formula 3. Drawings Fig. 1 is a schematic configuration diagram of a bending test apparatus according to an embodiment of the present invention. Fig. 2A is a front view of the bending imparting device of fig. 1. Fig. 2B is a sagittal sectional view taken along line B-B of fig. 2A. Fig. 2C is a diagram illustrating an operation of the bending imparting device of fig. 1. Fig. 2D is a diagram illustrating an operation of the bending imparting device of fig. 1. Fig. 3 is a diagram showing a calculation model in which a mandrel is arranged. Fig. 4 is a diagram showing a state in which no bending is imparted to the optical fiber. Fig. 5 is a diagram showing a state in which a part of the moving mandrel is moved to impart bending to the optical fiber. Fig. 6 is a diagram showing a state in which a part of the moving mandrel is moved to impart bending to the optical fiber. Fig. 7 is a diagram showing a state in which all the movable spindles are moved to impart bending to the optical fiber. Fig. 8 is a diagram showing an example in which a plurality of guide portions are arranged in parallel. Detailed Description [ Problem to be solved by the invention ] In the structure described in patent document 1, since the number of winding turns of the optical fiber is small, it is difficult to obtain the bending loss for the low bending loss single mode optical fiber. On the other hand, if the number of turns of the optical fiber is simply increased, efficiency is deteriorated, and the optical fiber is wound in a spiral shape, and the winding angle of the optical fiber is liable to be small, so that an accurate bending loss may not be obtained. In addition, when an optical fiber having a small diameter (for example, about 200 μm) is wound, the winding angle of the optical fiber tends to be small, and thus the bending loss may not be accurately obtained. The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a bending-loss-measuring bending-applying device and a bending t