Adjustable beam characteristics
Disclosed herein are methods, apparatus, and systems for providing an optical beam delivery device, comprising a first length of fiber comprising a first RIP formed to enable modification of one or more beam characteristics of an optical beam by a perturbation device and a second length of fiber having a second RIP coupled to the first length of fiber, the second RIP formed to confine at least a portion of the modified beam characteristics of the optical beam within one or more confinement regions.
1. An optical beam delivery device, comprising:
a first length of fiber comprising a first refractive index profile (RIP) formed to enable modification of two or more beam characteristics of a guided optical beam by a perturbation device; and
a second length of fiber having a second RIP coupled to the first length of fiber, the second RIP formed to confine at least a portion of the modified beam characteristics received from the first length of fiber within two or more confinement regions, wherein the first RIP and the second RIP are different and the first length of fiber and the second length of fiber form at least a portion of a continuous fiber length.
2. The optical beam delivery device of claim 1 , wherein the perturbation device is coupled to the first length of fiber or integral with the first length of fiber or a combination thereof.
3. The optical beam delivery device of claim 1 , wherein the first length of fiber comprises a graded-index RIP in at least a radially central portion and the second length of fiber has a first confinement region comprising a central core and a second confinement region that is annular and encompasses the first confinement region.
4. The optical beam delivery device of claim 3 , wherein the first confinement region and the second confinement region of the second length of fiber are separated by a cladding structure having a refractive index that is lower than the indexes of first confinement region and the second confinement region.
5. The optical beam delivery device of claim 4 , wherein the cladding structure comprises a fluorosilicate material.
6. The optical beam delivery device of claim 1 , wherein the first length of fiber or the second length of fiber or a combination thereof includes at least one divergence structure configured to modify a divergence profile of the optical beam and wherein the divergence structure comprises a first material having a lower index of refraction than a second material encompassing the divergence structure.
7. The optical beam delivery device of claim 6 , wherein the second length of fiber is azimuthally asymmetric and comprises a first confinement region comprising a first core and a second confinement region comprising a second core.
8. The optical beam delivery device of claim 7 , wherein the first confinement region and the second confinement region are coaxial.
9. The optical beam delivery device of claim 7 , wherein the first confinement region and the second confinement region are non-coaxial.
10. The optical beam delivery device of claim 9 , wherein the second confinement region is crescent shaped.
11. The optical beam delivery device of claim 1 , wherein the first RIP is parabolic in a first portion having a first radius.
12. The optical beam delivery device of claim 11 , wherein the first RIP is constant in a second portion having a second radius, wherein the second radius is larger than the first radius.
13. The optical beam delivery device of claim 1 , wherein the first RIP is a radially graded index extending to an edge of a core of the first length of fiber, wherein the first RIP is formed to increase or decrease a width of one or more modes of the optical beam responsive to the modification of the beam characteristics by the perturbation device.
14. The optical beam delivery device of claim 1 , wherein the first length of fiber has a radially graded index core extending to a first radius followed by a constant index portion extending to a second radius, wherein the second radius is larger than the first radius.
15. The optical beam delivery device of 1 , wherein the second length of fiber comprises a central core having a diameter in a range of about 0 to 100 microns, a first annual core encompassing the central core having a diameter in a range of about 10 to 600 microns and a second annular core having a diameter in a range of about 20 to 1200 microns.
16. The optical beam delivery device of claim 1 , wherein the perturbation device is a bending assembly configured to alter a bend radius or alter a bend length of the first length of fiber or a combination thereof to modify the beam characteristics of the optical beam.
17. The optical beam delivery device of claim 1 , wherein the first length of fiber and the second length of fiber are separate passive fibers that are spliced together.
18. The optical beam delivery device of claim 1 , wherein the perturbation device comprises a bending assembly, a mandrel, micro-bend in the fiber, an acousto-optic transducer, a thermal device, a fiber stretcher, or a piezo-electric device, or any combination thereof.
19. An optical beam delivery device, comprising:
a first length of fiber comprising a first refractive index profile (RIP) formed to enable modification of two or more beam characteristics of an optical beam by a perturbation device; and
a second length of fiber having a second RIP defining at least two confinement regions and coupled to the first length of fiber, the second RIP formed to confine at least a portion of the modified beam characteristics of the optical beam within the at least two confinement regions.
20. The optical beam delivery device of claim 19 , wherein the perturbation device is coupled to the first length of fiber or integral with the first length of fiber or a combination thereof.
21. The optical beam delivery device of claim 1 , wherein the second length of fiber is adapted to provide a processing beam to a workpiece, and the processing beam is based on the modified beam characteristics received from the first length of fiber.
22. The optical beam delivery device of claim 1 , wherein the second length of optical fiber is situated to direct the processing beam to the workpiece.
23. The optical beam delivery device of claim 1 , wherein at least two of the two or more confinement regions are coaxial.
24. The optical beam delivery device of claim 1 , wherein the first length of optical fiber is a single mode optical fiber.
25. The optical beam delivery device of claim 1 , further comprising a processing delivery fiber coupled to the second length of optical fiber and adapted to deliver a processing beam to a workpiece, wherein the processing beam is based on the modified beam characteristics.