Methods and systems for measuring target movement with an interferometer

1. An interferometer system, comprising:

a plurality of light sources, each light source of the plurality configured to transmit a source beam;

an interferometer including a polarizing beam splitter and a reference reflector and configured to receive the source beam and transmit a measurement beam to a target reflector and a reference beam to the reference reflector; and

a plurality of receivers, each receiver of the plurality associated with a light source and configured to receive a mixed output beam comprising a reflected measurement beam and a reflected reference beam;

wherein the interferometer is configured to receive at least one source beam transmitted at an angle with respect to an axis perpendicular to a side of the interferometer configured to receive the at least one source beam.

2. The system of claim 1 , further comprising a plurality of beam splitters, each beam splitter of the plurality positioned between the interferometer and an associated light source and configured to transmit the source beam to the interferometer and reflect the mixed output beam to an associated receiver.

3. The system of claim 2 , wherein each beam splitter of the plurality comprises a beam splitting interface and each polarizing beam splitter comprises a polarizing beam splitter interface.

4. The system of claim 1 , wherein the interferometer is configured to receive the at least one source beam transmitted at an angle of 15 degrees or less with respect to the axis perpendicular to the side of the interferometer configured to receive the at least one source beam.

5. The system of claim 1 , wherein each receiver of the plurality is configured to detect an optical interference signal of the mixed output beam.

6. The system of claim 1 , wherein the reference reflector comprises at least one of a reference corner cube and a mirror.

7. The system of claim 1 , wherein the interferometer comprises a Michelson interferometer.

8. The system of claim 1 , wherein each light source is configured to transmit a source beam through a single port in a chamber positioned between each light source and the interferometer.

9. The system of claim 1 , wherein at least one light source of the plurality is oriented to transmit a source beam at an angle of substantially 15 degrees or less with respect to the axis perpendicular to the side of the interferometer configured to receive the at least one source beam.

10. An interferometer system, comprising:

including a plurality of source-receiver devices, each source-receiver device a light source, a beam splitting interface, and a receiver; and

a common interferometer comprising a common polarizing beam splitter and a common reference reflector and configured to receive a source beam from each source-receiver device of the plurality of source-receiver devices;

wherein the interferometer system is configured to measure movement of a plurality of targets using the common interferometer.

11. A method of operating an interferometer system, comprising:

providing a plurality of light sources;

transmitting a source beam from each of the plurality of light sources to an interferometer, wherein at least one source beam is transmitted to the interferometer at an angle with respect to an axis perpendicular to a side of the interferometer configured to receive the at least one source beam; and

receiving a mixed output beam including an interference signal at a receiver associated with at least one light source of the plurality of light sources.

12. The method of claim 11 , wherein providing the plurality of light sources comprises providing a beam splitter associated with the receiver and each of the plurality of light sources.

13. The method of claim 12 , wherein transmitting the source beam from each of the plurality of light sources comprises transmitting the source beam from each of the plurality of light sources through the associated beam splitter to the interferometer.

14. The method of claim 11 , wherein transmitting the source beam from each of the plurality of light sources to the interferometer at the angle comprises transmitting the at least one source beam to the interferometer at an angle of substantially 15 degrees or less with respect to the axis perpendicular to the side of the interferometer configured to receive the at least one source beam.

15. The method of claim 11 , wherein transmitting the source beam from each of the plurality of light sources to the interferometer comprises transmitting the source beam from each of the plurality of light sources to an interferometer comprising a polarizing beam splitter and a reference reflector.

16. The method of claim 11 , further comprising transmitting a measurement beam to a target reflector and a reference beam to a reference reflector after transmitting the source beam to the interferometer.

17. The method of claim 16 , further comprising receiving a reflected measurement beam and a reflected reference beam at the interferometer after transmitting the measurement beam to the target reflector and the reference beam to the reference reflector.

18. The method of claim 11 , wherein providing the plurality of light sources comprises providing one or more light sources oriented at an angle with respect to the axis perpendicular to the side of the interferometer.

19. The method of claim 11 , wherein providing the plurality of light sources comprises providing a plurality of light sources, each light source of the plurality of light sources configured to transmit an associated source beam to the interferometer through a single window in an environmental chamber.

20. The method of claim 11 , wherein providing the plurality of light sources comprises providing a single laser configured to transmit a plurality of source beams.

21. The method of claim 20 , wherein transmitting the source beam comprises transmitting the plurality of source beams from the single laser to the interferometer via at least one of an optical fiber, one or more half-wave plates, and one or more on-axis folds.

22. The method of claim 11 , wherein receiving the mixed output beam including the interference signal at the receiver comprises receiving the mixed output beam transmitted from the interferometer through a beam splitter to the receiver via at least one of an optical fiber, one or more half-wave plates, and one or more on-axis folds.

23. A method of operating an interferometer system comprising:

measuring movement of a plurality of targets with a plurality of source-receiver devices by:

transmitting a source beam from each of the plurality of source-receiver devices to a common interferometer comprising to a common polarizing beam splitter and a common reference reflector; and

receiving a plurality of mixed output beams from the common interferometer, each mixed output beam received at a corresponding source-receiver device of the plurality of source-receiver devices.

24. An interferometer cluster system, comprising:

a plurality of interferometer systems, each interferometer system comprising:

an interferometer; and

a plurality of source-receiver devices, each source-receiver device configured to transmit a source beam to the interferometer and receive a mixed beam comprising a measurement beam and a reference beam, wherein at least one source-receiver device is oriented to transmit a source beam at an angle with respect to an axis perpendicular to a side of the interferometer configured to receive the source beam.

25. The system of claim 24 , wherein at least two interferometer systems of the plurality are configured to measure movement of at least one common target.