Coherently-combined multiple apertures

Patent metadata

Field	Value
Publication number	US-9838139-B2
Application number	US-201514982491-A
Country	US
Kind code	B2
Filing date	Dec 29, 2015
Priority date	Dec 29, 2015
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

Optical communication systems and methods using coherently combined optical beams are disclosed. A representative system includes a first mirror having a first actuator for adjusting a position of the first mirror in a path of a first optical beam and a first optical detector for receiving light reflected from the first mirror. The system also includes a second mirror having a second actuator for adjusting a position of the second mirror in a path of a second optical beam and a second optical detector for receiving light reflected from the second mirror. The system includes an interferometer for measuring an interference between the first and second optical beams and a third optical detector for receiving light from the second interfered optical beam. Intensity of the first interfered optical beam is increased by the interference, and intensity of the second interfered optical beam is decreased by the interference.

First claim

The invention claimed is:

1. An optical communication system for coherently combining optical beams, comprising:
a first mirror having a first actuator for adjusting a position of the first mirror in a path of a first optical beam;
a first optical detector for receiving light reflected from the first mirror;
a second mirror having a second actuator for adjusting a position of the second mirror in a path of a second optical beam;
a second optical detector for receiving light reflected from the second mirror;
an interferometer for measuring an interference between the first and second optical beams; and
a third optical detector for receiving light from a second interfered optical beam;
wherein at least one of the first actuator and the second actuator is actuated based on an output signal from the first optical detector or the second optical detector, and wherein a first intensity of a first interfered optical beam is increased by the interference, and a second intensity of the second interfered optical beam is decreased by the interference.

2. The optical system of claim 1 , further comprising an optical fiber for receiving the first interfered optical beam.

3. The optical system of claim 1 wherein the interference is measured at a beamsplitter.

4. The optical system of claim 1 wherein at least one of the first actuator and the second actuator is actuated based on an output signal from the third optical detector.

5. The optical system of claim 1 wherein:
the first actuator adjusts the position of the first mirror through a first tip, a first tilt, and a piston; and
the second actuator adjusts the position of the second mirror through a second tip and a second tilt.

6. The optical system of claim 1 , further comprising a controller for controlling the second actuator at least in part based on signals from the second detector and the third detector.

7. The optical system of claim 1 wherein the first and second optical detectors are position-sensitive detectors.

8. The optical system of claim 7 wherein the position-sensitive detectors are quad detectors.

9. The optical system of claim 1 , further comprising:
a beamsplitter for directing at least a portion of the first beam to the first optical detector and at least a portion of the second beam to the second optical detector.

10. A method for coherently combining optical beams, comprising:
receiving a first optical beam at least in part at a first optical detector;
receiving a second optical beam at least in part at a second optical detector, wherein the second optical beam is coherent with the first optical beam;
causing interference between the first optical beam and the second optical beam by intersecting the first and the second optical beams at a beamsplitter;
receiving a second interfered optical beam at least in part at a third optical detector;
adjusting a position of the first mirror using a first actuator, wherein the first mirror is in a path of the first optical beam;
adjusting a position of the second mirror using a second actuator, wherein the second mirror is in a path of the second optical beam; and
receiving a first interfered optical beam at least in part by an optical fiber, wherein a first intensity of the first interfered optical beam is increased by the interference, and a second intensity of the second interfered optical beam is decreased by the interference.

11. The method of claim 10 wherein adjusting the position of the first mirror and adjusting the position of the second mirror are based at least in part on outputs from the first optical detector and the second optical detector.

12. The method of claim 11 wherein adjusting the positions of the first mirror and adjusting the position of the second mirror are based at least in part on an output from the third optical detector.

13. The method of claim 11 wherein:
adjusting the position of the first mirror consists of adjusting a tip and a tilt of the first mirror, and
adjusting the position of the second mirror consists of adjusting a tip, a tilt and a piston of the second mirror.

14. The method of claim 10 wherein the first optical beam is directed to the optical fiber through a focusing lens.

15. The method of claim 10 wherein the first, the second and the third optical detectors are position-sensitive detectors.

16. The method of claim 15 wherein the position-sensitive detectors are quad detectors.

Assignees

• Facebook Inc

Inventors

• Birnbaum Kevin Michael
• Chen Chien-Chung

Classifications

• H04B10/11

  Arrangements specific to free-space transmission, i.e. transmission through air or vacuum · CPC title

• H04B10/114

  Indoor or close-range type systems · CPC title

• H04B10/071

  using a reflected signal, e.g. using optical time domain reflectometers [OTDR] · CPC title

• H04B10/615 Primary

  Arrangements affecting the optical part of the receiver · CPC title

• H04B10/60

  Receivers · CPC title