Quantum Signal Detection Using Photon Adders

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Solution Overview

Problem

Current quantum signal detection systems, such as LIDAR and RADAR, face limitations in resolution due to noise at the fundamental frequency level, particularly quantum noise, which degrades the clarity and precision of detected signals.

Innovation Solution

A quantum signal detection system that includes a photon adder to enhance the signal-to-noise ratio by adding photons to the return signal, either through a parametric amplifier or by interacting with atoms in a cavity, before mixing it with a reference signal using a beamsplitter, thereby altering photon statistics and reducing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If homodyne or heterodyne detection is used to detect the return signal, then the system can determine target location and range, but quantum noise (vacuum noise) decreases the clarity and resolution of the detected signal

Engineering Contradiction:

Improvesignal resolutionVSAvoidquantum noise

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a reference beam as an intermediary element that mixes with the return signal at a beamsplitter. This reference beam, which is coherent with the transmitted signal, serves as a mediator to extract phase or frequency information from the weak return signal while the homodyne or heterodyne detection process itself acts as the intermediary mechanism to convert the optical signal into a measurable electrical signal with improved signal-to-noise ratio

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary action by splitting the transmitted signal into a reference portion before the signal reaches the target. This reference signal is preserved and later used in the detection process to compare against the return signal, enabling phase or frequency measurement while compensating for quantum noise effects through the coherent mixing process

Inventive Principle:

Principle #10Preliminary action

2Power

If the return signal is combined with a stronger coherent signal, then the signal strength increases, but quantum noise inherent within the system decreases the clarity of the detected signal

Engineering Contradiction:

Improvesignal strengthVSAvoidsignal clarity

Core Design Contradiction:

PowerVSMeasurement precision

Solution Approach 1:

The patent converts the harmful effect of quantum noise into a benefit by using the vacuum noise field as a reference for homodyne detection. The quantum noise, which normally degrades signal quality, is transformed into a measurable signal component that can be processed to extract target information. The vacuum fluctuations serve as the local oscillator in the homodyne detection scheme, turning the noise source into a useful reference

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If LIDAR or RADAR systems are used to detect targets, then the system can measure distance and surface features, but the resolution is limited due to noise at the fundamental frequency level

Engineering Contradiction:

Improverange measurement accuracyVSAvoidfundamental frequency noise

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the conventional direct detection mechanical/electronic system with a quantum-based homodyne or heterodyne detection system. Instead of directly measuring the weak return signal with conventional detectors limited by fundamental noise, the system substitutes a quantum coherent mixing process that converts the measurement problem into a different domain where the signal can be extracted with higher precision above the noise floor

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This approach significantly improves the signal-to-noise ratio, leading to increased resolution and enhanced range and phase measurement capabilities, allowing for the detection of targets at greater distances with higher precision.

Implementation Method 1

The photon adder may include a parametric amplifier or downconverter

Methodology Applied

Scientific EffectParametric amplification:

Implementation Method 2

The photon adder may include a parametric amplifier or downconverter

Methodology Applied

Scientific EffectParametric downconversion:

Implementation Method 3

a beamsplitter that is configured to mix the combined signal with a reference signal

Methodology Applied

Scientific EffectOptical interference: Interference

Implementation Method 4

the photon adder may include a cavity having one or more atoms that are configured to interact with the return signal

Methodology Applied

Scientific EffectCavity quantum electrodynamics:

Data Source

PatentUS10107680B2Quantum signal detection systems and methods

Publication Date: 2018.10.23 THE BOEING CO

AI summary

A quantum signal detection system includes a signal source configured to emit a transmit signal towards a target, and a photon adder that is configured to add at least one photon to a return signal that reflects from the target to form a combined signal. The combined signal increases a signal to noise ratio of the return signal.