OPTICAL COUPLER AND METHOD OF BRANCHING LIGHT USING THE OPTICAL COUPLER

• US 20160299293A1
• Filed: 07/06/2015
• Published: 10/13/2016
• Est. Priority Date: 09/24/2014
• Status: Active Application

• Current Assignee: ISHIHARA SANGYO CO., LTD.
• Original Assignee: ISHIHARA SANGYO CO., LTD.
• Inventors: IIDA, Hidetoku, SHIRATORI, Hideaki
• Application Number:
  US14/898,601
• Publication Number:
  US 20160299293A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 6/283 couplers being tunable or adjustable
• CPC Class Codes: G02B 6/2835 formed or shaped by thermal treatment, e.g. couplers
• CPC Class Codes: G02B 6/2852 using tapping light guides arranged sidewardly, e.g. in a non-parallel relationship with respect to the bus light guides (light extraction or launching through cladding, with or without surface discontinuities, bent structures)
• CPC Class Codes: G02B 6/29332 Wavelength selective couplers, i.e. based on evanescent coupling between light guides, e.g. fused fibre couplers with transverse coupling between fibres having different propagation constant wavelength dependency non wavelength-selective light guide couplers G02B6/28
• CPC Class Codes: G02B 6/4289 by inducing bending, microbending or macrobending, to the light guide
• CPC Class Codes: G02B 6/4291 by accessing the evanescent field of the light guide

Abstract

Provided is an optical coupler, which can allow the light to be branched off by the required amount when necessary, and a method of branching light using the optical coupler. Optical coupler 1 has optical fiber 10 that has small-diameter part 12, which is formed so as to have a relatively small outer diameter at a portion in the longitudinal direction, and that branches off the transmitted light by small-diameter part 12; and output optical fiber 20 that receives the light branched off from input optical fiber 10. Small-diameter part 12 of input optical fiber 10 is caused to contact with linear small-diameter part 22 of output optical fiber 20; a coupling length, which is the length along which small-diameter part 12 of input optical fiber 10 and small-diameter part 22 of output optical fiber 20 are made to contact with each other, or a propagation constant of the optical fibers is varied; and thus, branching ratio S of the light branched off from input optical fiber 10 into output optical fiber 20 is varied.

Claims

1. An optical coupler, comprising:

an input optical fiber that has a small-diameter part, which has a relatively small outer diameter at a portion in the longitudinal direction, and that branches off transmitted light by the small-diameter part;

an output optical fiber that has a small-diameter part, which has a relatively small outer diameter at a portion in the longitudinal direction, and that receives the light branched off from the input optical fiber;

a curved part that is formed in the small-diameter parts of one or both of the input optical fiber and the output optical fiber; and

a coupling part at which the small-diameter part of the input optical fiber contacts with the small-diameter part of the output optical fiber, and in which coupling length is varied by varying pressing force of the input optical fiber and the output optical fiber, the coupling length being length along which the small-diameter part of the input optical fiber and the small-diameter of the out output of the optical fiber are made to contact with each other.

9. The optical coupler according to claim 1, wherein

the both of the small-diameter parts of the input optical fiber and the output optical fiber have the curved parts, respectively.

11. The optical coupler according to claim 1, wherein

one of the small-diameter parts of the input optical fiber and the output optical fiber has the curved part, and the other one of small-diameter parts of the input optical fiber and the output optical fiber is linearly formed.

2-4. -4. (canceled)

5. Branching light method, comprising:

using an optical coupler that has an input optical fiber and an output optical fiber, the input optical fiber having a small-diameter part, which has a relatively small outer diameter at a portion in the longitudinal direction, and branching off transmitted light by the small-diameter part; and

the output optical fiber having a small-diameter part, which has a relatively small outer diameter at a portion in the longitudinal direction, and receiving the light branched off from the input optical fiber, the both of the small-diameter parts being caused to contact with each other, one or both of the input optical fiber and the output optical fiber having the small-diameter parts that are curved, as a curved part,

varying pressing force of the input optical fiber and the output optical fiber, through utilization of elastic force in the curved parts, by making the input optical fiber and the output optical fiber approach one another, in order to increase coupling length which is length along which the small-diameter part of the input optical fiber and the small-diameter part of the output optical fiber are made to contact with each other, and by making the input optical fiber and the output optical fiber draw away from each other in order to decrease the coupling length; and

varying branching ratio of the light branched off from the input optical fiber into the output optical fiber by varying the pressing force.

6-8. -8. (canceled)

10. The optical coupler according to claim 69, further comprising:

a casing in which the input optical fiber and the output optical fiber are cased, and that has an upper surface member and an under surface member, opposing one another with a certain spacing therebetween; and

a fixing member that fixes the upper surface member and the under surface member in the casing with the certain spacing.