Multi-directional optical communications system and method with turbulence mitigation using homodyne encoding

Patent metadata

Field	Value
Publication number	US-12526046-B2
Application number	US-202318191244-A
Country	US
Kind code	B2
Filing date	Mar 28, 2023
Priority date	Mar 28, 2023
Publication date	Jan 13, 2026
Grant date	Jan 13, 2026

Abstract

Embodiments of the present invention include free-space optical communication systems and methods employing homodyne encoding on the receiver sides of the terminals that are configured to mitigate optical degradation due to atmospheric turbulence.

First claim

What is claimed is:

1 . A method for homodyne aperture reconstruction of a spatially encoded optical source light signal corrupted by atmospheric turbulence sent from a remote optical source, the method comprising:
providing a system for the homodyne aperture reconstruction of the source light signal; physically separating the source light signal to generate laterally separated light in a non-redundant array; collimating the laterally separated light to obtain laterally separated collimated light; focusing the laterally separated collimated light; capturing a time sample of the laterally separated collimated light; extracting spatially separated beat terms from the time sample; determining phase errors in the time sample of the spatially separated beat terms to obtain phase corrected optical data; determining jitter correction in the phase corrected optical data to obtain jitter corrected optical data; deconvolving the jitter corrected data using estimated power and noise spectra to obtain deconvolved optical data; and recombining the deconvolved optical data to obtain a corrected light signal.

2 . The method according to claim 1 , wherein the system comprises:
a multi-aperture primary beam separating interferometer; a multi-aperture secondary beam collimating interferometer spaced apart from the primary beam separating interferometer; and a sensor for capturing optical image data time samples.

3 . The method according to claim 2 , wherein the physically separating the source light signal further comprises passing the source light signal through the multi-aperture primary beam separating interferometer to generate the laterally separated light.

4 . The method according to claim 2 , wherein the collimating the laterally separated light further comprises passing the laterally separated light through the secondary multi-aperture beam collimating interferometer to obtain the laterally separated collimated light.

5 . The method according to claim 2 , wherein the focusing the laterally separated collimated light further comprises focusing the laterally separated collimated light onto the sensor.

6 . The method according to claim 2 , wherein the capturing the time sample further comprises capturing the time sample with the sensor.

7 . The method according to claim 2 , further comprising calibrating the system for homodyne aperture reconstruction.

8 . The method according to claim 7 , wherein the calibrating further comprises:
creating an initial calibration dataset; and computing initial offset shifts to obtain baseline spatial shifts.

9 . The method according to claim 2 , wherein the multi-aperture primary beam separating interferometer and the multi-aperture secondary beam collimating interferometer comprise a matched pair of three-aperture interferometer assemblies.

10 . The method according to claim 1 , wherein the determining phase errors, further comprises:
solving for any phase errors in the time sample of the spatially separated beat terms by forcing computed overlapped regions to be in phase; and spatially placing frequency information back into correct locations as defined prior to separation.

11 . A non-transitory computer readable media storing computer readable software instructions that when executed by a processor causes the processor implementing the method for homodyne aperture reconstruction of a spatially encoded optical source light signal corrupted by atmospheric turbulence sent from a remote optical source recited in claim 1 .

12 . The method according to claim 1 , wherein the spatially encoded optical source light signal comprises multiple spatially encoded optical source light signals within a viewing field.

13 . The system according to claim 12 , wherein the data acquisition module further comprises a sensor array.

14 . A system for homodyne aperture reconstruction of a spatially encoded optical source light signal corrupted by atmospheric turbulence sent from a remote optical source comprising:
an input optical setup module configured to receive the corrupted light signal and present a focused, laterally separated, corrupted light signal; a data acquisition module configured to capture at least one time sample of the focused, laterally separated, corrupted light signal; and an image processing module configured to correct phase errors and jitter in the at least one time sample and generate corrected image data, the image processing module further comprising:
a spatially separated beat terms extractor;
a phase error corrector;
a jitter corrector;
a deconvolver; and
a recombiner.

15 . The system according to claim 14 , wherein the spatially encoded optical source light signal comprises multiple spatially encoded optical source light signals within a viewing field.

16 . The system according to claim 14 , wherein the input optical setup further comprises:
a primary aperture interferometer, the primary aperture interferometer configured to receive the corrupted light signal and laterally separate the corrupted light signal; a secondary aperture interferometer including three secondary apertures in communication with the primary aperture interferometer and configured to collimate the laterally separated, corrupted light signal; and focusing optics in communication with the secondary aperture interferometer and configured to focus the collimated laterally separated, corrupted light signal.

17 . The system according to claim 16 , wherein the primary aperture interferometer further includes three primary apertures, wherein each of the three primary apertures further comprise:
a diameter, d 1 , of about 12.7 mm; and center-to-center spacing, s 1 , of about 13.7 mm, relative to one another.

18 . The system according to claim 17 , wherein the secondary aperture interferometer includes three secondary apertures, wherein each of the three secondary apertures further comprise:
a diameter, d 2 , of about 25.4 mm; and center-to-center spacing, s 2 , of about 44.0 mm, relative to one another.

19 . The system according to claim 18 , wherein the primary apertures and the secondary apertures are matched and separated by a distance, s 3 , of about 50 mm.

20 . The system according to claim 18 , wherein the primary apertures and the secondary apertures each further comprise:
a blazed diffraction grating with 300 lines per mm; a blaze angle of about 11.25°; a diffraction efficiency of about 60%; a center wavelength of about 670 nm; and a blaze arrow direction toward beamline's center.

21 . The data acquisition module, according to claim 14 , wherein the data acquisition module comprises a visible-band camera.

22 . An optical communications system including a plurality of optical transceivers in communication with each other, each transceiver comprising:
a transmitter; and a system for homodyne aperture reconstruction, the system further comprising:
a receiver adapted for receiving a spatially encoded optical source light signal corrupted by atmospheric turbulence;
a processor in communication with the receiver; and
a memory in communication with the processor configured to store a computer program adapted for implementing a method for homodyne aperture reconstruction of a spatially encoded optical source light signal corrupted by atmospheric turbulence sent from a remote optical source; and
wherein the method further comprises:
providing a system for the homodyne aperture

Assignees

• Us Navy

Inventors

• Drexler Kyle Robert
• Neuner Iii Burton Hamilton
• Lilledahl Skylar Darious Jones
• Laxton Benjamin

Classifications

• H04B10/1129 Primary

  Arrangements for outdoor wireless networking of information · CPC title

• H04B10/1123 Primary

  Bidirectional transmission · CPC title