Multimode beam combiner

Patent metadata

Field	Value
Publication number	US-10114172-B2
Application number	US-201715474073-A
Country	US
Kind code	B2
Filing date	Mar 30, 2017
Priority date	Jun 20, 2016
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

An up-taper is applied by a mode adapter to increase a signal mode area prior to tapering and combining.

First claim

What is claimed is:

1. A fiber combining system, comprising:
(a) mode adapters, each mode adapter comprising:
(a1) a core, comprising:
(a1A) a core input end having an input fundamental mode field diameter (MFD); and
(a1B) a core output end having an output fundamental MFD, the output fundamental MFD being larger than the input fundamental MFD;
(a1C) a mode expander between the core input end and the core output end; and
(a1D) a core index of refraction; and

(a2) a cladding surrounding the core, the cladding comprising a cladding index of refraction, the cladding index of refraction being less than the core index of refraction; and

(b) a combiner, comprising:
(b1) a combiner input end optically coupled to the adapters' core output ends;
(b2) a combiner output end; and
(b3) a down-tapered region between the combiner input end and the combiner output end.

2. The system of claim 1 , wherein the mode expander increases a mode area of an optical beam as the optical beam propagates through the mode expander.

3. The system of claim 1 , wherein the down-tapered region decreases a mode area of an optical beam as the optical beam propagates through the down-tapered region.

4. The system of claim 1 , wherein the mode adapter comprises a tapered multi-mode (MM) optical fiber.

5. The system of claim 4 , wherein:
the core output diameter is between approximately 50 micrometers (˜50 μm) and ˜100 μm; and
the cladding has an outer diameter of between ˜110 μm and ˜125 μm.

6. The system of claim 4 , wherein the MM optical fiber comprises the mode expander and the core input end, the core input being MM with a fundamental mode field diameter (MFD), the system further comprising:
an input fiber for propagating a fundamental mode, the input fiber having an input fiber MFD that matches the MM fundamental mode MFD.

7. The system of claim 1 , further comprising an input fiber optically coupled to the core input.

8. The system of claim 1 , wherein the input fiber is configured to transmit a fundamental mode.

9. The system of claim 1 , wherein the combiner input diameter is more than three (3) times larger than the combiner output diameter.

10. A system, comprising:
a mode adapter comprising a mode expander that progressively increases a mode area of an optical beam as the optical beam travels through the mode expander, wherein the mode adapter comprises multi-mode (MM) optical fibers arranged in a close-packed configuration, wherein each MM optical fiber comprises a MM core, the MM core comprising:
a MM input end having a MM input fundamental mode field diameter (MFD) and a MM core input numerical aperture (NA); and
a MM output end having a MM output fundamental MFD, the MM output fundamental MFD being larger than the MM input MFD; and

a combiner optically coupled to the mode adapter, the combiner comprising a down-tapered region that progressively decreases the mode area of the optical beam as the optical beam travels through the down-tapered region.

11. The system of claim 10 , further comprising:
an input single-mode (SM) optical fiber having a SM output end, the SM output end being optically coupled to the MM input end, the SM optical fiber having a SM output mode field diameter (MFD), the SM output MFD substantially matching the MM input fundamental MFD.

12. The system of claim 10 , wherein the mode adapter is configured to lower beam divergence as the optical beam travels through the mode adapter.

13. The system of claim 10 , wherein the down-tapered region is tapered by a factor greater than 3.

Assignees

• Ofs Fitel Llc

Inventors

• Holland William R
• Thalman Cassandra

Classifications

• G02B6/3825

  with an intermediate part, e.g. adapter, receptacle, linking two plugs · CPC title

• G02B6/02004

  characterised by the core effective area or mode field radius · CPC title

• G02B6/26 Primary

  Optical coupling means (G02B6/36, G02B6/42 take precedence) · CPC title

• G02B6/0288 Primary

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

• G02B6/2808

  using a mixing element which evenly distributes an input signal over a number of outputs · CPC title