Fiber encapsulation mechanism for energy dissipation in a fiber amplifying system

Patent metadata

Field	Value
Publication number	US-10992096-B2
Application number	US-201815972680-A
Country	US
Kind code	B2
Filing date	May 7, 2018
Priority date	Oct 17, 2016
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

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. A multi-stage optical fiber amplifier, comprising:
a preamplifying stage, comprising:
a first optical fiber comprising a gain medium; and
a first pump source arranged to optically pump the first optical fiber, wherein optically pumping the first optical fiber amplifies optical signals in a wavelength range transmitted through the gain medium of the first optical fiber; and

a booster amplifying stage, comprising:
a second optical fiber comprising a gain medium, wherein the second optical fiber is optically coupled to the first optical fiber and arranged to receive optical signals from the first optical fiber;
a polymer layer that at least partially surrounds the second optical fiber, wherein the polymer layer is optically transparent;
a second pump source arranged to optically pump the second optical fiber, wherein optically pumping the second optical fiber amplifies optical signals in the wavelength range transmitted through the gain medium of the second 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 second 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 second optical fiber.

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

3. The multi-stage optical fiber amplifier of claim 2 ,
wherein at least a portion of the second optical fiber comprises a second cladding layer that surrounds the cladding layer, and
wherein the second optical fiber is less than 2 meters in length.

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

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

6. The multi-stage optical fiber amplifier of claim 5 , wherein 900 nm is included in the wavelength range for short range or midrange light detection and ranging (LIDAR) applications or 1.55 μm is included in the wavelength range for long range LIDAR applications.

7. The multi-stage optical fiber amplifier of claim 1 , wherein the polymer layer comprises a polymer material and an additional material, wherein the additional material increases a thermal conductivity of the polymer layer.

8. The multi-stage optical fiber amplifier of claim 7 , wherein the additional material comprises a binary salt of fluoride.

9. The multi-stage optical fiber amplifier of claim 7 , wherein the additional material does not substantially decrease the optical transparency of the polymer layer.

10. The multi-stage optical fiber amplifier of claim 1 , further comprising a third optical fiber, wherein a first end of the third optical fiber is joined to the first optical fiber, and wherein a second end of the third optical fiber is joined to the second optical fiber at a fusion splice.

11. The multi-stage optical fiber amplifier of claim 10 , wherein the polymer layer surrounds the fusion splice.

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

13. The multi-stage optical fiber amplifier of claim 1 , wherein the multi-stage optical fiber amplifier is a two-stage optical fiber amplifier.

14. The multi-stage 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 multi-stage optical fiber amplifier of claim 1 , wherein the second optical fiber is less than 2 meters in length.

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

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

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

19. A method, comprising:
optically pumping, by a first pump source, a first optical fiber comprising a gain medium, wherein optically pumping the first optical fiber amplifies optical signals in a wavelength range transmitted through the gain medium of the first optical fiber, and wherein the first pump source and the first optical fiber are components of a preamplifying stage;
transmitting, to a second optical fiber comprising a gain medium, amplified optical signals from the first optical fiber;
optically pumping, by a second pump source, the second optical fiber, wherein optically pumping the second optical fiber amplifies optical signals in the wavelength range transmitted through the gain medium of the second optical fiber, and wherein optically pumping the second optical fiber generates excess heat and excess photons;
transmitting, to a polymer layer that at least partially surrounds the second optical fiber, the excess heat and the excess photons, wherein the polymer layer is optically transparent;
conducting, by a heatsink layer disposed adjacent to the polymer layer, the excess heat away from the second optical fiber; and
transmitting, by an optically transparent layer disposed adjacent to the polymer layer opposite the heatsink layer, the excess photons away from the second optical fiber, wherein the second optical fiber, the second pump source, the polymer layer, the heatsink layer, and the optically transparent layer are components of a booster amplifying stage.

20. A light detection and ranging (LIDAR) system, comprising:
a transmitter configured to emit a signal, wherein the transmitter comprises a multi-stage optical fiber amplifier, and wherein the multi-stage optical fiber amplifier comprises:
a preamplifying stage, comprising:
a first optical fiber comprising a gain medium; and
a first pump source arranged to optically pump the first optical fiber, wherein optically pumping the first optical fiber amplifies optical signals in a wavelength range transmitted through the gain medium of the first optical fiber; and
a booster amplifying stage, comprising:
a second optical fiber comprising a gain medium, wherein the second optical fiber is optically coupled to the first optical fiber and arranged to receive optical signals from the first optical fiber;
a polymer layer that at least partially surrounds the second optical fiber, wherein the polymer layer is optically transparent;
a second pump source arranged to optically pump the second optical fiber, wherein optically pumping the second optical fiber amplifies optical signals in the wavelength range transmitted through the gain medium of the second 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 second optical fiber; and
an optically transparent layer disposed adjacent to the polymer layer opposite the heats

Assignees

• Waymo Llc

Inventors

• Fidric Bernard
• Rosenfeld Daniel
• Pardhan Rahim

Classifications

• H01S3/0064

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