Fiber encapsulation mechanism for energy dissipation in a fiber amplifying system

Patent metadata

Field	Value
Publication number	US-9787048-B1
Application number	US-201615294886-A
Country	US
Kind code	B1
Filing date	Oct 17, 2016
Priority date	Oct 17, 2016
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

The present disclosure relates to a fiber encapsulation mechanism for energy dissipation in a fiber amplifying system. One example embodiment includes an optical fiber amplifier. The optical fiber amplifier includes an optical fiber that includes a gain medium, as well as a polymer layer that at least partially surrounds the optical fiber. The polymer layer is optically transparent. In addition, the optical fiber amplifier includes a pump source. Optical pumping by the pump source amplifies optical signals in the optical fiber and generates excess heat and excess photons. The optical fiber amplifier additionally includes a heatsink layer disposed adjacent to the polymer layer. The heatsink layer conducts the excess heat away from the optical fiber. Further, the optical fiber amplifier includes an optically transparent layer disposed adjacent to the polymer layer. The optically transparent layer transmits the excess photons away from the optical fiber.

First claim

What is claimed:

1. An optical fiber amplifier, comprising:
an optical fiber comprising a gain medium;
a polymer layer that at least partially surrounds the optical fiber,
wherein the polymer layer is optically transparent,
wherein the polymer layer comprises a polymer material and an additional material, and
wherein the additional material increases a thermal conductivity of the polymer layer;

a pump source configured to optically pump the optical fiber, wherein optical pumping by the pump source amplifies optical signals in a wavelength range transmitted through the gain medium of the optical fiber and generates excess heat and excess photons;
a heatsink layer disposed adjacent to the polymer layer, wherein the heatsink layer conducts the excess heat away from the optical fiber; and
an optically transparent layer disposed adjacent to the polymer layer opposite the heatsink layer, wherein the optically transparent layer transmits the excess photons away from the optical fiber.

2. The optical fiber amplifier of claim 1 , wherein the optical fiber comprises a core that includes the gain medium and a cladding layer that surrounds the core.

3. The optical fiber amplifier of claim 2 , wherein at least a portion of the optical fiber comprises a second cladding layer that surrounds the cladding layer.

4. The optical fiber amplifier of claim 1 , wherein the gain medium comprises erbium or ytterbium.

5. The optical fiber amplifier of claim 1 , wherein the wavelength range includes 1.55 μm, 1.05 μm, or 900 nm.

6. The optical fiber amplifier of claim 3 , wherein the second cladding layer comprises a thermally conductive dopant to increase thermal conductivity.

7. The optical fiber amplifier of claim 1 , wherein the additional material comprises a binary salt of fluoride.

8. The optical fiber amplifier of claim 1 , wherein the additional material does not substantially decrease the optical transparency of the polymer layer.

9. The optical fiber amplifier of claim 1 , further comprising a passive optical fiber that is joined to the optical fiber comprising the gain medium at a fusion splice.

10. The optical fiber amplifier of claim 9 , wherein the polymer layer surrounds the fusion splice.

11. The optical fiber amplifier of claim 1 , wherein the polymer layer can withstand temperatures up to 200 degrees Celsius.

12. The optical fiber amplifier of claim 1 , wherein the polymer layer has a refractive index between 1.37 and 1.40.

13. The optical fiber amplifier of claim 1 , wherein the optically transparent layer comprises glass.

14. The optical fiber amplifier of claim 1 , wherein the optical fiber amplifier is a transmitting component of a light detection and ranging (LIDAR) system, and wherein the optical signals are scattered by objects within a scene and detected by a receiver of the LIDAR system to analyze the scene.

15. The optical fiber amplifier of claim 1 , wherein the optical fiber is less than 2 meters in length.

16. The optical fiber amplifier of claim 1 , wherein the optically transparent layer further defines a minimum distance from the optical fiber at which the excess photons may be absorbed.

17. The optical fiber amplifier of claim 1 , wherein the optically transparent layer further mechanically protects the polymer layer from damage.

18. The optical fiber amplifier of claim 1 , further comprising a pulsed seed laser, wherein the pulsed seed laser seeds the optical fiber with the optical signals in the wavelength range.

19. A method, comprising:
optically pumping, by a pump source, an optical fiber comprising a gain medium, wherein optically pumping by the pump source amplifies optical signals in a wavelength range transmitted through the gain medium of the optical fiber and generates excess heat and excess photons;
transmitting, to a polymer layer that at least partially surrounds the optical fiber, the excess heat and the excess photons,
wherein the polymer layer is optically transparent,
wherein the polymer layer comprises a polymer material and an additional material, and
wherein the additional material increases a thermal conductivity of the polymer layer;

conducting, by a heatsink layer disposed adjacent to the polymer layer, the excess heat away from the optical fiber; and
conducting, by an optically transparent layer disposed adjacent to the polymer layer opposite the heatsink layer, the excess photons away from the optical fiber.

20. A method of assembling an optical fiber amplifier, comprising:
connecting an output end of a pump source to an input end of an optical fiber, wherein the optical fiber comprises a gain medium, wherein the pump source is configured to optically pump the optical fiber to amplify optical signals in a wavelength range transmitted through the gain medium of the optical fiber, and wherein optically pumping the optical fiber to amplify optical signals generates excess heat and excess photons;
placing at least a portion of the optical fiber adjacent to a heatsink layer, wherein the heatsink layer conducts the excess heat away from the optical fiber;
surrounding the portion of the optical fiber adjacent to the heatsink layer with a polymer layer,
wherein the polymer layer is optically transparent,
wherein the polymer layer comprises a polymer material and an additional material, and
wherein the additional material increases a thermal conductivity of the polymer layer; and

placing an optically transparent layer adjacent to the polymer layer opposite the heatsink layer, wherein the optically transparent layer transmits the excess photons away from the optical fiber.

21. The method of claim 20 , further comprising:
curing the polymer layer so the polymer layer undergoes a phase change from a liquid to a solid and adheres to the optical fiber, the heatsink layer, and the optically transparent layer.

Assignees

• Waymo Llc

Inventors

• Fidric Bernard
• Rosenfeld Daniel
• Pardhan Rahim

Classifications

• H01S3/094003

  the pumped medium being a fibre · CPC title

• H01S3/094069

  Multi-mode pumping · CPC title

• H01S3/1618

  ytterbium · CPC title

• H01S3/06758

  Tandem amplifiers · CPC title

• H01S3/0405 Primary

  Conductive cooling, e.g. by heat sinks or thermo-electric elements · CPC title