Rotary optical beam generator

1. An optical fiber device, comprising:

a core including a primary section and a secondary section,

wherein the secondary section includes at least one insert element inserted within the primary section, the at least one insert element being inserted at an off-center location with respect to a center of the primary section,

wherein the secondary section twists about an axis of the optical fiber device along a length of the optical fiber device,

wherein a rate of twist at which the secondary section twists about the axis increases from a first rate of twist at a first end of the optical fiber device to a second rate of twist at a second end of the optical fiber device, and

wherein the secondary section being twisted about the axis is to cause an optical beam, launched at the first end of the optical fiber device, to be at least partially converted to a rotary optical beam at the second end of the optical fiber device; and

a cladding surrounding the core.

2. The optical fiber device of claim 1 , wherein the at least one insert element has a round cross section.

3. The optical fiber device of claim 1 , wherein the secondary section includes two or more insert elements inserted within the primary section.

4. The optical fiber device of claim 1 , wherein the at least one insert element is formed from a doped silica or a non-doped silica.

5. The optical fiber device of claim 1 , wherein the at least one insert element comprises a fluid or a vacuum contained within an opening in the primary section.

6. The optical fiber device of claim 1 , wherein a cross-sectional diameter of the at least one insert element is less than approximately 5% of a diameter of the primary section.

7. The optical fiber device of claim 1 , wherein a cross-sectional size of the at least one insert element increases along a portion of the length of the optical fiber device in a direction from the first end of the optical fiber device toward the second end of the optical fiber device.

8. The optical fiber device of claim 1 , wherein a cross-sectional size of the at least one insert element decreases along a portion of the length of the optical fiber device in a direction from the first end of the optical fiber device toward the second end of the optical fiber device.

9. The optical fiber device of claim 1 , wherein a cross-sectional size of the at least one insert element is near zero at the first end of the optical fiber device.

10. The optical fiber device of claim 1 , wherein a cross-sectional size of the at least one insert element is near zero at the second end of the optical fiber device.

11. A method comprising:

receiving, by a rotator fiber, an optical beam at a first end of the rotator fiber,

wherein the rotator fiber comprises a core including a primary section and a secondary section,

wherein the secondary section includes at least one insert element inserted within the primary section, the at least one insert element being inserted at an off-center location with respect to a center of the primary section,

wherein the secondary section twists about an axis of the rotator fiber along a length of the rotator fiber, and

wherein a rate of twist at which the secondary section twists about the axis increases from a first rate of twist at the first end of the rotator fiber to a second rate of twist at a second end of the rotator fiber;

at least partially converting, by the rotator fiber, the optical beam to a rotary optical beam,

wherein the optical beam is at least partially converted as a result of the secondary section being twisted about the axis; and

outputting, by the rotator fiber, the rotary optical beam.

12. The method of claim 11 , wherein the at least one insert element has a round cross section.

13. The method of claim 11 , wherein the secondary section includes six or fewer insert elements inserted within the primary section.

14. The method of claim 11 , wherein the at least one insert element is formed from a doped silica or a non-doped silica.

15. The method of claim 11 , wherein the at least one insert element comprises a liquid, a gas, a gas mixture, or a vacuum contained within an opening in the primary section.

16. The method of claim 11 , wherein a cross-sectional size of the at least one insert element increases along a portion of the length of the rotator fiber in a direction from the first end of the rotator fiber toward the second end of the rotator fiber.

17. The method of claim 11 , wherein a cross-sectional size of the at least one insert element decreases along a portion of the length of the rotator fiber in a direction from the first end of the rotator fiber toward the second end of the rotator fiber.

18. The method of claim 11 , wherein a cross-sectional size of the at least one insert element is near zero at the first end of the rotator fiber or at the second end of the rotator fiber.

19. An annular beam generator, comprising:

an optical fiber device including:

a core including a primary section and a secondary section,

wherein the secondary section includes a set of insert elements inserted within the primary section, the set of insert elements being inserted at respective off-center locations with respect to a center of the primary section, and

wherein the secondary section twists about an axis of the optical fiber device along a length of the optical fiber device,

wherein a rate of twist at which the secondary section twists about the axis increases from a first rate of twist at a first end of the optical fiber device to a second rate of twist at a second end of the optical fiber device.

20. The annular beam generator of claim 19 , wherein a cross-sectional size of the set of insert elements varies along a portion of the length of the optical fiber device from the first end of the optical fiber device toward the second end of the optical fiber device.

21. A method, comprising:

providing a fiber preform including a primary section;

forming an opening in the primary section of the fiber preform along a length of the fiber preform, the opening being offset from a central axis of the fiber preform;

inserting an insert element in the opening of the primary section of the fiber preform to create a secondary section of the fiber preform, the insert element being inserted at an off-center location with respect to a center of the primary section of the fiber preform; and

consolidating, drawing, and twisting the fiber preform to generate a twisted rotator fiber,

wherein, as a result of the twisting, the secondary section twists about an axis of the twisted rotator fiber along a length of the twisted rotator fiber,

wherein a rate of twist at which the secondary section twists about the axis increases from a first rate of twist at a first end of the fiber preform to a second rate of twist at a second end of the fiber preform, and

wherein the secondary section being twisted about the axis is to cause an optical beam, launched at the first end of the optical fiber device, to be at least partially converted to a rotary optical beam at the second end of the optical fiber device.