Direct impingement cooling of fibers

Patent metadata

Field	Value
Publication number	US-10007077-B2
Application number	US-201414440378-A
Country	US
Kind code	B2
Filing date	Aug 21, 2014
Priority date	Sep 4, 2013
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A system provides for a way for cooling an optical fiber. The system includes a coolant and a conduit. The conduit allows the coolant to flow through the conduit. At least part of the fiber passes through the conduit allowing the coolant to flow around the at least part of the fiber. In some configurations, the fiber runs parallel to the conduit. The system can include a pump diode that is part of an optical laser connected to an end of the fiber. The optical laser can further include a high reflector connected to the fiber and a partial reflector connected to the fiber to reflect some light back and forth between the high reflector and the partial reflector.

First claim

What is claimed is:

1. A method of cooling an optical fiber during laser beam generation comprising:
receiving optical energy in a prefabricated completely solid and non-hollow static optical fiber;
reflecting the optical energy along the completely solid static optical fiber between a first reflector and a second reflector to generate a laser beam, wherein the reflecting turns some of the optical energy into mechanical heat energy;
actively flowing a liquid coolant inside a main conduit from an input conduit adjacent to an outer surface of the completely solid and non-hollow static optical fiber to an output conduit so that the liquid coolant directly impinges on the outer surface of the completely solid and non-hollow static optical fiber while the laser beam is generated and the completely solid static optical fiber precludes the liquid coolant from impinging the optical fiber at a location other than the outer surface, wherein the main conduit is coupled with the input conduit and the output conduit in a manner to maintain the coolant in a pressurized state;
tensioning the completely solid and non-hollow static optical fiber with a first low stress coupler connected to a first end of the main conduit and with a second low stress coupler connected to a second end of the main conduit, wherein the input conduit and the output conduit are located between the first and second low stress couplers; and
reducing stress and pressure on the completely solid and non-hollow static optical fiber with the first low stress coupler connected to the first end of the main conduit, and an O-ring in the first low stress coupler extending around the completely solid and non-hollow static optical fiber, and reducing stress and pressure on the completely solid and non-hollow static optical fiber with the second low stress coupler connected to the second end of the conduit, and an O-ring in the second low stress coupler extending around the solid static optical fiber.

2. The method of cooling an optical fiber of claim 1 further comprising:
actively flowing the liquid coolant parallel to the outer surface of the completely solid and non-hollow static optical fiber that is part of a fiber laser between the first reflector and the second reflector, wherein the first reflector and the second reflector are exterior to the main conduit.

3. The method of cooling an optical fiber of claim 1 wherein the actively flowing a liquid further comprises: actively flowing water parallel to a longitudinal axis of the completely solid and non-hollow static optical fiber.

4. The method of cooling an optical fiber of claim 2 wherein the main conduit is a cylindrically shaped conduit and further comprising:
maintaining the completely solid and non-hollow static optical fiber at a central axis of the conduit and parallel to the main conduit with the low stress coupler at each end of the main conduit, wherein each O-ring extends around the completely solid and non-hollow static optical fiber; and
spreading out a stress exerted on the completely solid and non-hollow static optical fiber by the liquid coolant directly impinging the completely solid and non-hollow static optical fiber.

5. The method of cooling an optical fiber of claim 2 wherein the solid static optical fiber is a first fiber and further comprising:
actively flowing a liquid coolant parallel to a second fiber inside the conduit; and
reducing pressure on the completely solid and non-hollow static optical fiber with a pressure reducing device that retains the completely solid and non-hollow static optical fiber centrally in the main conduit.

6. The method of cooling an optical fiber of claim 2 further comprising:
re-cooling liquid coolant exiting near the first end of the main conduit; and
re-injecting re-cooled liquid coolant near the second end of the main conduit.

7. The method of cooling an optical fiber of claim 4 further comprising:
placing a spacer between the elongated conduit and the completely solid and non-hollow static optical fiber to space the completely solid and non-hollow static optical fiber away from the main conduit and still allow the liquid coolant to impinge the outer surface of the completely solid and non-hollow static optical fiber;
wherein the spacer positions the completely solid and non-hollow static optical fiber centrally in the main conduit and the spacer is located inside the main conduit between the input conduit and the output conduit.

8. The method of cooling an optical fiber of claim 1 further comprising:
pumping light into the solid static optical fiber with a pump diode that is part of a fiber laser, wherein the pump diode is exterior to the main conduit and exterior to the first and second low stress couplers connected to the main conduit.

9. A system for cooling an optical fiber during laser beam generation comprising:
a prefabricated solid static optical fiber adapted to receive optical energy;
a first reflector and a second reflector positioned along the solid static optical fiber adapted to reflect optical energy therebetween and generate a laser beam;
a liquid coolant;
a conduit adapted to allow the coolant to flow through the conduit, wherein the first reflector and the second reflector are inside the conduit;
wherein at least part of the solid static optical fiber passes through the conduit allowing the coolant to flow at least parallel to at least part of an outer surface of the solid static optical fiber to impinge and actively cool the solid static optical fiber while the laser beam is generated and actively cool the first reflector and the second reflector inside the conduit;
wherein the coolant flows in one direction parallel to the solid static optical fiber;
wherein the first reflector is a high reflector connected to the solid static optical fiber;
wherein the second reflector is a partial reflector connected to the solid static optical fiber to reflect some light back and forth between the high reflector and the partial reflector;
a first low stress coupler connected to a first end of the conduit to reduce stress on the solid static optical fiber and pressure in the optical fiber, and an O-ring in the first low stress coupler extending around the solid static optical fiber;
a second low stress coupler connected to the second end of the conduit to reduce stress on the solid static optical fiber and pressure in the optical fiber, and an O-ring in the second low stress coupler extending around the solid static optical fiber;
a coolant input conduit in fluid communication with the conduit;
a coolant output conduit in fluid communication with the conduit, wherein the coolant input conduit and the coolant output conduit are located between the first low stress coupler and the second low stress coupler; and
wherein the conduit is coupled with the coolant input conduit and the coolant output conduit in a manner to maintain the coolant in a pressurized state.

10. The system for cooling an optical fiber of claim 9 wherein the at least part of the solid static optical fiber runs parallel to the conduit.

11. The system for cooling an optical fiber of claim 9 wherein a pump diode is located within the conduit and is adapted to be cooled by the coolant.

12. The system for cooling an optical fiber of claim 9 wherein the solid static optical fiber is a first optical fiber and the system further comprising:
a second solid static optical fiber in the conduit allowing the coolant to flow around the second solid static optical fiber to cool the second solid static optical fiber.

13. The system for cooling an optical fiber of claim 12 wherein the second solid

Assignees

• Bae Systems Information And Electronics Systems Integration Inc
• Bae Sys Inf & Elect Sys Integ

Inventors

• Johnson Benjamin R

Classifications

• H01S5/02423

  Liquid cooling, e.g. a liquid cools a mount of the laser · CPC title

• H01S5/0243

  Laser is immersed in the coolant, i.e. the whole laser chip is immersed in the liquid for cooling · CPC title

• G02B6/44 Primary

  Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables (cables incorporating electric conductors and optical fibres {where features relating to the optical fibres are not of interest} H01B11/22) · CPC title

• H01S3/094003

  the pumped medium being a fibre · CPC title

• H01S3/0404

  Air- or gas cooling, e.g. by dry nitrogen · CPC title