Enhanced microbend sensor

Patent metadata

Field	Value
Publication number	US-2020003589-A1
Application number	US-201916432213-A
Country	US
Kind code	A1
Filing date	Jun 5, 2019
Priority date	Jun 28, 2018
Publication date	Jan 2, 2020
Grant date	—

Abstract

An optical fiber sensor includes a first single mode fiber, a second single mode fiber, and a multimode fiber positioned between, and coupled to, the first single mode fiber and the second single mode fiber. The multimode fiber includes a graded-index core with an outer diameter between about 35 μm and about 45 μm. A numerical aperture of the core is between about 0.15 and about 0.25. The multimode fiber includes a cladding with an outer diameter between about 70 μm and about 90 μm. A coupling strength of an LP 01 mode of the first single mode fiber to each of an LP 02 mode and an LP 03 mode of the multimode fiber is at least about 0.25.

First claim

What is claimed is:

1 . An optical fiber sensor, comprising:
a first single mode fiber comprising a core and a cladding; a second single mode fiber comprising a core and a cladding; and a multimode fiber positioned between, and coupled to, the first single mode fiber and the second single mode fiber, the multimode fiber comprising:
a graded-index core having an outer diameter between about 35 μm and about 45 μm, wherein a numerical aperture of the core is between about 0.15 and about 0.25;
a cladding having an outer diameter between about 70 μm and about 90 μm; and
wherein a coupling strength of an LP 01 mode of the first single mode fiber to each of an LP 02 mode and an LP 03 mode of the multimode fiber is at least about 0.25.

2 . The optical fiber sensor of claim 1 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to the LP 02 mode of the multimode fiber is at least about 0.35.

3 . The optical fiber sensor of claim 2 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to the LP 03 mode of the multimode fiber is at least about 0.28.

4 . The optical fiber sensor of claim 3 , wherein the LP 02 and the LP 03 modes of the multimode fiber coherently interfere as light propagates through the multimode fiber.

5 . The optical fiber sensor of claim 2 , wherein a coupling strength of an LP 01 mode of the second single mode fiber to the LP 02 mode of the multimode fiber is at least about 0.40.

6 . The optical fiber sensor of claim 5 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to the LP 03 mode of the multimode fiber is at least about 0.30.

7 . The optical fiber sensor of claim 1 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to an LP 01 mode of the multimode fiber is less than about 0.90.

8 . The optical fiber sensor of claim 7 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to the LP 03 mode of the multimode fiber is at least about 0.30.

9 . The optical fiber sensor of claim 1 , wherein the core of the first single mode fiber has an outer diameter between about 4 μm and about 8 μm a maximum relative refractive index between about 0.4% and about 1.2%, and a cladding diameter of the first single mode fiber is between about 70 μm and about 90 μm.

10 . The optical fiber sensor of claim 9 , wherein the core of the second single mode fiber has an outer diameter between about 4 μm and about 8 μm a maximum relative refractive index between about 0.4% and about 1.2%, and a cladding diameter of the second single mode fiber is between about 70 μm and about 90 μm.

11 . An optical fiber sensor, comprising:
a first single mode fiber comprising a core and a cladding; a second single mode fiber comprising a core and a cladding; and a multimode fiber positioned between, and coupled to, the first single mode fiber and the second single mode fiber, the multimode fiber comprising:
a graded-index core having an outer radius of about 20 μm, wherein a numerical aperture of the core is about 0.20;
a cladding having an outer radius of about 40 μm; and
wherein an LP 01 mode of the first single mode fiber is closely matched to a central positive lobe of an LP 02 mode of the multimode fiber such that a coupling strength of the LP 01 mode of the first single mode fiber to each of an LP 02 mode and an LP 03 mode of the multimode fiber is at least about 0.25.

12 . The optical fiber sensor of claim 11 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to the LP 02 mode of the multimode fiber is at least about 0.35.

13 . The optical fiber sensor of claim 12 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to the LP 03 mode of the multimode fiber is at least about 0.28.

14 . The optical fiber sensor of claim 13 , wherein the LP 02 and the LP 03 modes of the multimode fiber coherently interfere as light propagates through the multimode fiber.

15 . The optical fiber sensor of claim 12 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to the LP 02 mode of the multimode fiber is at least about 0.40.

16 . The optical fiber sensor of claim 15 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to the LP 03 mode of the multimode fiber is at least about 0.30.

17 . The optical fiber sensor of claim 11 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to an LP 01 mode of the multimode fiber is less than about 0.90.

18 . The optical fiber sensor of claim 11 , wherein the coupling strength of the LP 01 mode of the first single mode fiber to an LP 01 mode of the multimode fiber is less than about 0.85.

19 . The optical fiber sensor of claim 13 , wherein the core of the first single mode fiber has a core having an outer diameter between about 4 μm and about 8 μm and a maximum relative refractive index between about 0.4% and about 1.2%, and a cladding diameter of the first single mode fiber is between about 70 μm and about 90 μm.

20 . The optical fiber sensor of claim 19 , wherein the core of the second single mode fiber has a core having an outer diameter between about 4 μm and about 8 μm and a maximum relative refractive index between about 0.4% and about 1.2%, and a cladding diameter of the second single mode fiber is between about 70 μm and about 90 μm.

Assignees

• Corning Inc

Inventors

• Bickham Scott Robertson

Classifications

• G01D5/35374 Primary

  Particular layout of the fiber · CPC title

• G02B2006/1209

  Multimode · CPC title

• G02B6/12

  of the integrated circuit kind (electric integrated circuits H10B, H10D84/00 - H10D89/00, H10F19/00, H10F39/00, H10H29/00, H10K19/00, H10K39/00, H10K59/00, H10N19/00, H10N39/00, H10N59/00, H10N69/00, H10N79/00, H10N89/00) · CPC title

• G02B6/0288

  Multimode fibre, e.g. graded index core for compensating modal dispersion · CPC title

• G02B2006/12138

  Sensor · CPC title