Coherent beam combination (CBC) systems and methods

Patent metadata

Field	Value
Publication number	US-12249803-B2
Application number	US-202418591069-A
Country	US
Kind code	B2
Filing date	Feb 29, 2024
Priority date	Jul 19, 2018
Publication date	Mar 11, 2025
Grant date	Mar 11, 2025

Abstract

A coherent beam combination (CBC) system ( 10 ) includes an array of beam sources ( 12 a, 12 b and 12 c ) generating coherent beams directed towards a target (T). The phase modulators ( 14 a, 14 b and 14 c ) allow adjustment of relative phase offsets of the beams. A detector ( 16 ) monitors an intensity of the radiation impinging on an area of the target (T). A controller ( 18 ) receives the intensity parameter and controls a phase adjustment of the beams according to a deterministic (i.e., quantitative) measurement of a phase offset of each beam relative to a representative phase of the sum of all the other beams. This is achieved by using interferometric techniques, referred to herein as Target In-the-Loop Interferometry (TILI).

First claim

What is claimed is:

1. A coherent beam combination (CBC) system comprising:
(a) an array of beam sources configured to generate a plurality of coherent beams and transmit the plurality of coherent beams towards a target;
(b) a plurality of adjustable phase modulators associated with said array of beam sources so as to allow adjustment of relative phase offsets of said transmitted coherent beams;
(c) a detector deployed for monitoring a reflected intensity parameter that varies as a function of an intensity of radiation of said transmitted coherent beams impinging on an area of the target; and
(d) a controller comprising logic circuitry, said controller being associated with said detector to receive said reflected intensity parameter and with said plurality of adjustable phase modulators to control a phase adjustment of said transmitted coherent beams, said controller being configured to actuate said plurality of adjustable phase modulators so as to maximize said reflected intensity parameter,

wherein said detector is associated with a telescope arrangement for collecting radiation reflected from the target and directing the reflected radiation to the detector, said telescope arrangement comprising a wavefront sensor for measuring optical distortions in the reflected radiation, a deformable mirror and an adaptive optics controller, said adaptive optics controller being associated with the wavefront sensor and operative to control the deformable mirror so as to reduce optical distortions in the reflected radiation based on measurements from the wavefront sensor.

2. The CBC system of claim 1 , wherein said telescope arrangement further comprises a beamsplitter providing a first channel that passes the reflected radiation from the deformable mirror to the wavefront sensor and a second channel that passes at least part of the reflected radiation to said detector.

3. The CBC system of claim 2 , further comprising a second beamsplitter that directs part of the reflected radiation passed by the second channel to said detector and directs part of the reflected radiation passed by the second channel to an imaging sensor for forming images of the target.

4. The CBC system of claim 3 , further comprising a control system electrically associated with the imaging sensor for receiving the images from the imaging sensor to control operation of the CBC system.

5. The CBC system of claim 4 , wherein the operation controlled by the control system includes one or more of target selection and correction of aiming.

6. The CBC system of claim 1 , wherein said controller is configured to actuate said plurality of adjustable phase modulators so as to maximize said reflected intensity parameter by performing a phase correction derived from a calculated phase offset of a current phase of each transmitted coherent beam relative to a representative phase of the sum of all the other transmitted coherent beams.

7. The CBC system of claim 1 , wherein said controller is configured to actuate said plurality of adjustable phase modulators so as to maximize said reflected intensity parameter by actuating each adjustable phase modulator of said plurality of adjustable phase modulators to modulate a current phase of a corresponding one of said transmitted coherent beams between at least three phase states.

8. The CBC system of claim 1 , wherein said controller is configured to actuate said plurality of adjustable phase modulators so as to maximize said intensity parameter by:
(i) identifying variations in the intensity parameter resulting from a modulation of a current phase of each transmitted coherent beam relative to the sum of all the other transmitted coherent beams, and
(ii) calculating based on said variations a phase offset of the current phase of each transmitted coherent beam relative to a representative phase of the sum of all the other transmitted coherent beams.

9. The CBC system of claim 1 , wherein said controller is configured to actuate said plurality of adjustable phase modulators so as to maximize said intensity parameter by:
(i) actuating each adjustable phase modulator of said plurality of adjustable phase modulators to modulate a current phase of a corresponding one of said transmitted coherent beams at a modulation frequency, and
(ii) identifying variations in reflected intensity occurring at more than one harmonic of said modulation frequency.

10. The CBC system of claim 1 , wherein said controller is configured to actuate said plurality of adjustable phase modulators so as to maximize said reflected intensity parameter by varying a current phase of a plurality of the transmitted coherent beams simultaneously, the current phase of each transmitted coherent beam of said plurality of the transmitted coherent beams being modulated at a distinct modulation frequency.

11. The CBC system of claim 1 , wherein said controller is configured to actuate said plurality of adjustable phase modulators so as to maximize said reflected intensity parameter by modulating a current phase of each transmitted coherent beam in a manner selected from the group consisting of: a continuous manner over a range of modulation frequencies encompassing at least three phase states, and a stepped manner between at least three phase states.

Assignees

• Rafael Advanced Defense Systems Ltd

Inventors

• Golubchik Daniel
• Segev Yehonathan
• Shwa David

Classifications

• H01S3/2308

  Amplifier arrangements, e.g. MOPA · CPC title

• H01S3/10053

  Phase control · CPC title

• H01S3/10092

  Coherent seed, e.g. injection locking · CPC title

• H01S3/067

  Fibre lasers · CPC title

• H01S3/1305

  Feedback control systems · CPC title