Optical beam expander with partial monolithic structure

1. An optical beam expander comprising:

a monolithic structure comprising:

a first nonplanar mirror that receives a first collimated optical beam having a first width and reflects the first collimated optical beam to generate a noncollimated optical beam; and

a second nonplanar mirror that receives a diverging optical beam and reflects the diverging optical beam to generate a second collimated optical beam having a second width greater than the first width,

wherein the first nonplanar mirror and the second nonplanar mirror are fixed in orientation and position relative to each other; and

a planar mirror that reflects the noncollimated optical beam from the first nonplanar mirror to provide the diverging optical beam to the second nonplanar mirror.

2. The optical beam expander of claim 1 , wherein the first nonplanar mirror comprises a concave mirror that reflects the first collimated optical beam toward the planar mirror as a converging optical beam.

3. The optical beam expander of claim 2 , wherein the converging optical beam forms a focal point between the first nonplanar mirror and the planar mirror at which the converging optical beam transitions to the diverging optical beam.

4. The optical beam expander of claim 3 , further comprising a field stop located at the focal point.

5. The optical beam expander of claim 1 , wherein the first collimated optical beam and the second collimated optical beam are skewed relative to each other.

6. The optical beam expander of claim 5 , wherein the first collimated optical beam and the second collimated optical beam are oriented 90 degrees relative to each other.

7. The optical beam expander of claim 1 , wherein the first nonplanar mirror and the second nonplanar mirror are each an integral portion of the monolithic structure.

8. The optical beam expander of claim 7 , wherein each of the first nonplanar mirror and the second nonplanar mirror comprises a material deposited onto a surface of the monolithic structure.

9. The optical beam expander of claim 1 , wherein the first nonplanar mirror and the second nonplanar mirror may comprise at least one concave mirror.

10. The optical beam expander of claim 1 , wherein an adjustment of the planar mirror is limited to three or fewer degrees of freedom.

11. The optical beam expander of claim 10 , wherein the three or fewer degrees of freedom comprise at least one of tip, tilt, or piston.

12. A method comprising:

reflecting, at a first reflective nonplanar surface coupled to a monolithic structure, toward a planar mirror, a first collimated optical beam having a first width to generate a noncollimated optical beam;

reflecting, at the planar mirror, the noncollimated optical beam from the first reflective nonplanar surface toward a second reflective nonplanar surface coupled to the monolithic structure; and

reflecting the noncollimated optical beam received at the second reflective nonplanar surface from the planar mirror to produce a second collimated optical beam having a second width greater than the first width, wherein the first reflective nonplanar surface and the second reflective nonplanar surface are fixed in orientation and position relative to each other.

13. The method of claim 12 , wherein the second collimated optical beam is skewed relative to the first collimated optical beam.

14. The method of claim 13 , wherein the second collimated optical beam is oriented 90 degrees relative to the first collimated optical beam.

15. The method of claim 12 , wherein:

the first reflective nonplanar surface comprises a first concave paraboloid mirror; and

the second reflective nonplanar surface comprises a second concave paraboloid mirror.

16. An optical beam telescope comprising:

a beam generation subsystem that generates a first light carrying transmission data;

an optical subsystem that processes the first light to generate a first collimated optical beam having a first width; and

an optical beam expander comprising:

a monolithic structure comprising:

a first nonplanar mirror that reflects the first collimated optical beam to generate a noncollimated optical beam; and

a second nonplanar mirror that receives a diverging optical beam and reflects the diverging optical beam to generate a second collimated optical beam having a second width greater than the first width, wherein the second collimated optical beam carries the transmission data through free space;

wherein the first nonplanar mirror and the second nonplanar mirror are fixed in orientation and position relative to each other; and

a planar mirror that reflects the noncollimated optical beam from the first nonplanar mirror as the diverging optical beam toward the second nonplanar mirror.

17. The optical beam telescope of claim 16 , wherein:

the second nonplanar mirror receives a third collimated optical beam having the second width and reflects the third collimated optical beam toward the planar mirror to generate a converging optical beam, wherein the third collimated optical beam carries reception data through free space;

the planar mirror reflects the converging optical beam from the second nonplanar mirror toward the first nonplanar mirror;

the first nonplanar mirror reflects the converging optical beam toward the optical subsystem to generate a fourth collimated optical beam having the first width;

the optical subsystem processes the fourth collimated optical beam to generate a second light carrying the reception data; and

the optical beam telescope further comprises a beam detection subsystem that processes the second light to recover the reception data.

18. The optical beam telescope of claim 17 , wherein the optical beam expander receives the first collimated optical beam and the third collimated optical beam simultaneously.