Method and apparatus for increasing fiber laser output power
A fiber laser with reduced stimulated Brillouin scattering includes a spool having a height and characterized by an induced temperature gradient with the height. The fiber laser also includes a fiber wrapped on the spool and characterized by a signal power increasing along the length of the fiber. The induced temperature gradient is a function of the signal power along the fiber.
1. A fiber laser with reduced stimulated Brillouin scattering, the fiber laser comprising:
a spool having a height and characterized by:
a material property varying as a function of the height; and
a predetermined temperature gradient as a function of the height;
a fiber having a length, wherein the fiber is coupled to the spool and characterized by a continuous temperature gradient as a function of the length of the fiber; and
a controller coupled to the spool and configured to provide the predetermined temperature gradient as a function of height of the spool.
2. The fiber laser of claim 1 wherein the material property comprises a groove pitch of the fiber.
3. The fiber laser of claim 1 wherein the material property comprises a wall thickness of the spool.
4. The fiber laser of claim 1 wherein the material property comprises a thermal conductivity of the spool.
5. The fiber laser of claim 1 wherein a first portion of the spool is characterized by a first temperature and a second portion of the spool is characterized by a second temperature, the second temperature being different from the first temperature.
6. The fiber laser of claim 1 further comprising
a second spool having a second height and characterized by:
a second material property varying as a function of the second height; and
a second predetermined temperature gradient as a function of the second height.
7. The fiber laser of claim 1 wherein the spool is characterized by a diameter that is nonuniform as a function of height.
8. The fiber laser of claim 1 wherein the fiber comprises a gain fiber and a passive fiber.
9. A fiber laser with reduced stimulated Brillouin scattering, the fiber laser comprising:
a spool having a height and characterized by an induced temperature gradient with the height and a material property varying as a function of height;
a fiber wrapped on the spool and characterized by a signal power increasing along the length of the fiber, wherein the induced temperature gradient is a function of the signal power along the fiber; and
a controller coupled to the spool and configured to provide the induced temperature gradient with height.
10. The fiber laser of claim 9 wherein the function is a monotonically increasing function.
11. The fiber laser of claim 9 wherein the induced temperature gradient is induced by a first temperature at a first portion of the spool and a second temperature different from the first temperature at a second portion of the spool.
12. The fiber laser of claim 9 wherein a wall thickness of the spool is nonuniform with the height.
13. The fiber laser of claim 9 wherein a wrapping pitch of the fiber on the spool is nonuniform with height.
14. The fiber laser of claim 9 further comprising:
a second spool having a second height and characterized by:
a second material property varying as a function of the second height; and
a second predetermined temperature gradient as a function of the second height.
15. The fiber laser of claim 9 wherein a thermal conductivity of the spool is nonuniform with height.
16. The fiber laser of claim 9 wherein a diameter of the spool is nonuniform with height.
17. The fiber laser of claim 9 wherein the fiber comprises a gain fiber and a passive fiber.
18. A fiber laser system comprising:
a seed source;
a fiber amplifier configured to receive the seed source, wherein the fiber amplifier includes:
a spool having a first surface and a second surface, a distance between the first surface and the second surface defining a spool height, wherein the spool is characterized by a predetermined temperature gradient as a function of the spool height; and
a fiber having a length, wherein the fiber is coupled to the spool and characterized by a continuous temperature gradient as a function of the length of the fiber;
a pump source optically coupled to the fiber amplifier; and
a temperature controller in electrical communication with the spool.
19. The fiber laser of claim 18 wherein the material property comprises a groove pitch of the fiber.
20. The fiber laser of claim 18 wherein the material property comprises a wall thickness of the spool.
21. The fiber laser of claim 18 wherein the material property comprises a thermal conductivity of the spool.
22. The fiber laser of claim 18 wherein the spool is characterized by a diameter that is nonuniform as a function of height.
23. The fiber laser of claim 18 wherein the fiber comprises a gain fiber and a passive fiber.