IP Library Granted Patent US 12,712,638
Granted Patent B2
US 12,712,638 · App. 18/632,647 · Granted Aug 18, 2026

Free-space optical communication sensors

Inventors: Joseph Hollmann (Cambridge, MA); Leonardo Gallo (Cambridge, MA); Kerri Cahoy (Cambridge, MA); Paul Serra (Cambridge, MA)
Assignee: The Charles Stark Draper Laboratory, Inc.
H04B10/60H04B10/11
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Quick Facts
Patent No.
US 12,712,638
App. No.
18/632,647
Granted
Aug 18, 2026
Kind
B2
Abstract

An optical sensor system for communication and pointing may include an optical sensor having photocells arranged in an array configured to receive at least one optical signal, and the optical sensor, in response to the optical signal, generating a first output signal and a second output signal, wherein the first output signal represents instantaneous photon flux of the received optical signal and the second output signal represents a derivative of the instantaneous photon flux of the received optical signal where the optical sensor operates as a dual communication and pointing sensor.

Claims (26)

1 . An optical sensor system for communication and pointing, comprising:

an optical sensor having photocells arranged in an array configured to receive at least one optical signal; and

the optical sensor, in response to the at least one optical signal, generating a first output signal and a second output signal, wherein the first output signal is a slow output for pointing and represents instantaneous photon flux of the at least one received optical signal and the second output signal is a fast output for communication and represents a derivative of the instantaneous photon flux of the at least one received optical signal where the optical sensor operates as a dual communication and pointing sensor.

2 . The sensor system of claim 1 , wherein the optical sensor comprises a silicon photomultiplier.

3 . The sensor system of claim 1 , wherein each of the photocells are spaced from each adjacent photocell by a predefined distance.

4 . The sensor system of claim 1 , wherein the first output signal is a pointing signal is between 100 hertz (Hz)-1 Kilohertz (KHz).

5 . The sensor system of claim 1 , wherein the second output signal is a free space optical signal at 200 Megahertz (MHz).

6 . An optical sensor for communication and pointing, comprising:

a plurality of photocells configured to receive at least one optical signal,

in response to the at least one optical signal, configured to generate a first output signal and a second output signal, wherein the first output signal represents instantaneous photon flux of the at least one received optical signal and the second output signal represents a derivative of the instantaneous photon flux of the at least one received optical signal.

7 . The sensor of claim 6 , wherein the plurality of photocells are arranged in a quadratic matrix.

8 . The sensor of claim 7 , wherein the plurality of photocells include four photocells in a two-by-two quadratic arrangement configured to receive at least one optical signal.

9 . The sensor system of claim 6 , wherein the optical sensor comprises a silicon photomultiplier.

10 . The sensor system of claim 6 , wherein each of the photocells are spaced from each adjacent photocell by a predefined distance.

11 . The sensor system of claim 6 , wherein the first output signal is a pointing signal is between 100 hertz-1 Kilohertz (KHz).

12 . The sensor system of claim 6 , wherein the second output signal is a free space optical signal at 200 Megahertz (MHz).

13 . The sensor system of claim 6 , wherein each of the plurality of photocells has a quadrilateral shape.

14 . An optical communication system comprising:

a laser;

a fine pointing system configured to direct an output of the laser in a direction according to a control signal;

an optical sensor configured to detect an optical signal impinging thereon and simultaneously produce a first output signal and a second output signal, wherein the first output signal represents instantaneous photon flux of the optical signal impinging on the optical sensor and the second output signal represents a derivative of the instantaneous photon flux of the optical signal impinging on the optical sensor; and

a controller configured to:

receive the first and second output signals from the optical sensor;

generate the control signal according to the first output signal from the optical sensor; and

generate a communication output signal according to the second output signal from the optical sensor.

15 . The system of claim 14 , wherein the optical sensor comprises a silicon photomultiplier.