Rotary optical beam generator

1. An optical fiber device, comprising:

a unitary core including a primary section and a secondary section,

wherein at least a portion of the secondary section is offset from a center of the unitary core,

wherein the unitary core twists about an optical axis of the optical fiber device along a length of the optical fiber device,

wherein a rate of twist at which the unitary core twists about the optical 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 unitary core being twisted about the optical axis causes 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

wherein a refractive index of the primary section is greater than a refractive index of the secondary section; and

a cladding surrounding the unitary core.

2. The optical fiber device of claim 1 , wherein the primary section has a first refractive index, the cladding has a second refractive index, and the secondary section has a third refractive index,

wherein the first refractive index is greater than the second refractive index and the third refractive index, and

wherein third refractive index is greater than or equal to the second refractive index.

3. The optical fiber device of claim 1 , wherein the secondary section is arranged within the unitary core such that the secondary section separates the primary section into at least two sections.

4. The optical fiber device of claim 3 , wherein the at least two sections includes four sections.

5. The optical fiber device of claim 3 , wherein the at least two sections have approximately equal cross-sectional areas.

6. The optical fiber device of claim 1 , wherein the secondary section is arranged within the unitary core such that the secondary section forms a partial divider in the primary section.

7. The optical fiber device of claim 1 , wherein a cross-section of the secondary section is symmetric with respect to the optical axis of the optical fiber device.

8. The optical fiber device of claim 1 , wherein the secondary section comprises at least three portions,

wherein the at least three portions extend in directions that are perpendicular to the optical axis of the optical fiber device in a plane of a cross-section of the optical fiber device.

9. The optical fiber device of claim 1 , wherein the first rate of twist at the first end of the optical fiber device is less than or equal to one twist per 50 millimeters.

10. The optical fiber device of claim 1 , wherein the optical fiber device is tapered such that a size of the optical fiber device at the first end of the optical fiber device is smaller than a size of the optical fiber device at the second end of the optical fiber device.

11. The optical fiber device of claim 1 , wherein the rotary optical beam includes light propagating in at least one rotary guided mode or at least one rotary leaky wave.

12. The optical fiber device of claim 11 , wherein at least one of:

a rotational quantum number, associated with a rotary guided mode of the at least one rotary guided mode or a rotary leaky wave of the at least one rotary leaky wave, is greater than or equal to four.

13. The optical fiber device of claim 1 , wherein the rotary optical beam has an annular shape at the second end of the optical fiber device.

14. The optical fiber device of claim 1 , wherein the optical beam has a first rotational state and the rotary optical beam has a second rotational state,

wherein the first rotational state is different from the second rotational state.

15. The optical fiber device of claim 14 , wherein the optical beam and the rotary optical beam are circularly polarized optical beams.

16. The optical fiber device of claim 14 , wherein the optical beam is a multi-mode optical beam and the rotary optical beam includes multiple rotary guided modes or rotary leaky waves.

17. The optical fiber device of claim 14 , wherein the optical beam is a single mode optical beam and the rotary optical beam includes multiple rotary output modes or rotary leaky waves.

18. The optical fiber device of claim 14 , wherein the optical beam is a single mode optical beam, and

wherein at least 50% of input power, associated with the optical beam, is converted to a single rotary guided mode or a single rotary leaky wave in the rotary optical beam.

19. An optical fiber device, comprising:

a unitary core including a primary section,

wherein the primary section of the unitary core has a non-circular shape,

wherein the unitary core twists about an optical axis of the optical fiber device along a length of the optical fiber device

wherein a rate of twist at which the unitary core twists about the optical 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 unitary core being twisted about the optical axis causes 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 unitary core.

20. The optical fiber device of claim 19 , wherein a perimeter of the non-circular shape is at least partially concave.

21. A method, comprising:

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

wherein the rotator fiber includes a unitary core that twists about an optical axis of the rotator fiber along a length of the rotator fiber,

wherein a rate of twist at which the unitary core twists about the optical axis increases from a first rate of twist at a 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 to the rotary optical beam as a result of the unitary core being twisted about the optical axis; and

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

22. The method of claim 21 , wherein the rotator fiber is tapered such that a size of the rotator fiber at the first end of the rotator fiber is smaller than a size of the rotator fiber at the second end of the rotator fiber.

23. The optical fiber device of claim 19 , wherein the optical fiber device is tapered such that a size of the optical fiber device at the first end of the optical fiber device is smaller than a size of the optical fiber device at the second end of the optical fiber device.