Coherent Optical Signal Combining for Long-Range Laser Data Links

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Solution Overview

Problem

Optical communication systems using high-power lasers face energy reduction issues due to phase mismatches between laser signals, leading to incomplete signal transmissions over long distances, similar to the challenges faced by laser-directed energy weapon systems.

Innovation Solution

A method and apparatus that coherently combine optical signals with different characteristics, such as phase and wavelength, using an adjustment unit to align these signals for improved energy deposition and transmission, including the use of laser generators and optical signal combiners to create a combined optical signal with increased intensity and directionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If laser beams are combined without phase adjustment, then the system structure is simple, but energy deposition at the target is reduced due to phase mismatches and interference

Engineering Contradiction:
Improveenergy depositionVSAvoidsystem structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent adjusts the phase parameter of individual laser beams using phase modulators or delay lines to achieve constructive interference at the target. By changing the phase parameter of each beam, the system maximizes energy deposition while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system employs feedback mechanisms where the phase and intensity of combined laser beams are monitored and adjusted in real-time. This feedback control ensures optimal energy deposition at the target while compensating for atmospheric turbulence and phase drift.

Inventive Principle:
Principle #23Feedback

2Length of stationary object

If optical signals are transmitted over long distances, then communication range is extended, but signal energy is reduced due to phase mismatches and atmospheric effects

Engineering Contradiction:
Improvetransmission distanceVSAvoidsignal energy
Core Design Contradiction:
Length of stationary objectVSLoss of energy

Solution Approach 1:

The system dynamically adjusts the phase and wavelength parameters of optical signals to compensate for atmospheric turbulence and propagation effects over long distances. This parameter optimization maintains signal energy and enables successful transmission to non-stationary targets.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamic phase and wavelength adjustment mechanisms that adapt to changing atmospheric conditions and target motion. This dynamic adaptation allows the system to maintain coherent beam combining and signal integrity over extended transmission distances.

Inventive Principle:
Principle #15Dynamics

3Loss of information

If multiple optical signals with different characteristics are combined, then signal differentiation and information capacity are improved, but phase alignment becomes more complex

Engineering Contradiction:
Improvesignal differentiationVSAvoidphase alignment complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The system uses different wavelength parameters for different optical signals while maintaining phase coherence through independent phase control for each wavelength. This approach enables signal differentiation for information transmission while managing phase alignment complexity through separate control channels.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the optical signal transmission into multiple wavelength channels, each with independent phase control. This segmentation allows different characteristics for different signals while simplifying the overall phase alignment problem by treating each wavelength independently.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables the generation and transmission of a combined optical signal with increased intensity and directionality, capable of successful signal transmission over long distances and to non-stationary targets, while allowing for differentiated and phase-separated optical signals.

Implementation Method 1

Coherent beam combining is one such method, wherein the phase of each laser beam is adjusted until all the beams from a plurality of beams are in phase with each other.

Methodology Applied
Scientific EffectCoherent beam combining: Interference

Implementation Method 2

The adjustment unit is configured to adjust at least one characteristic from at least one of the first and/or second sets of characteristics of the first and second optical signals.

Methodology Applied
Scientific EffectPhase adjustment: Phase Modulation

Data Source

PatentEP4529046A1Laser directed energy weapon for an optical data link
Publication Date: 2025.03.26 BAE SYSTEMS PLC
  • EP4529046A1 patent drawingFigure 1
  • EP4529046A1 patent drawingFigure 2
  • EP4529046A1 patent drawingFigure 3a~3b

AI summary

An apparatus 100 is configured to transmit an optical signal. The apparatus 100 comprises a first optical signal generator 102, configured to generate a first optical signal 106 comprising a first set of characteristics; a second optical signal generator 104, configured to generate a second optical signal 108 comprising a second set of characteristics; an adjustment unit 110, configured to adjust at least one of the different characteristics of at least one of the first and/or second optical signals 106, 108; and an optical signal combiner 116, configured to combine the first and second optical signals 106, 108 into a combined optical signal 118. The first and second sets of characteristics are different. Also described herein is an apparatus 200 configured to receiving an optical signal 202. The apparatus 200 comprises at least one sensor 204, configured to detect a combined optical data signal 202; and a processor 208. The processor 208 is configured to identify, from the combined optical signal 202, a first optical signal based on a first wavelength component; identify, from the combined optical signal, a second optical signal based on a second wavelength component; and extract data from the first optical signal based on the second optical signal. Also described herein is a method of transmitting 600 and a method of receiving 700 an optical signal, for example, using the transmitter and receiver apparatuses 100, 200.