Quantum Network Phase Synchronization via Optical Modulation

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Solution Overview

Problem

Photon exchange based quantum networks face significant challenges due to high photon loss during transmission, especially when using optical fibers, and require stable phase relations between quantum network nodes, which is difficult to maintain over long distances.

Innovation Solution

The implementation of optical phase and/or frequency modulators in the detection station to synchronize light from different quantum network nodes, combined with the use of optical frequency converters at the nodes to convert photon wavelengths to standard communication fiber frequencies, reducing loss and maintaining phase stability without additional compensation measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If photons are transmitted through optical fibers from quantum network nodes to detection station, then the network can operate over long distances, but photon loss increases significantly

Engineering Contradiction:

Improvetransmission distanceVSAvoidphoton loss

Core Design Contradiction:

Length of stationary objectVSLoss of energy

Solution Approach 1:

The patent converts the wavelength parameter of photons from quantum network nodes to match the optimal transmission window of standard optical fibers (1550 nm). This parameter change enables photons to be transmitted through long-distance optical fiber infrastructure with minimized loss, resolving the contradiction between transmission distance and photon loss.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If standard optical fibers are used for photon transmission, then infrastructure cost is reduced and long-distance transmission is enabled, but phase stability becomes difficult to maintain

Engineering Contradiction:

Improvephoton lossVSAvoidphase stability

Core Design Contradiction:

Loss of energyVSStability of the object's composition

Solution Approach 1:

The patent performs preliminary wavelength conversion at the quantum network nodes before photons enter the optical fiber transmission medium. This preliminary action ensures photons are pre-configured for optimal transmission through standard fibers, eliminating the need for complex phase stabilization infrastructure while maintaining phase coherence over long distances.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If quantum network nodes use non-standard photon wavelengths, then node functionality is maintained, but transmission loss increases in optical fibers

Engineering Contradiction:

Improvenode functionalityVSAvoidtransmission loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent introduces wavelength converters as intermediary devices at quantum network nodes. These converters act as mediators that transform photons from node-specific wavelengths to the universal 1550 nm standard used by optical fiber infrastructure, enabling both node functionality preservation and low-loss transmission through standard fibers.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 reduces photon loss and maintains synchronization of light phases across the network, enabling efficient entanglement generation and use of standard optical communication fibers, even over long distances like those to satellites.

Implementation Method 1

optical phase and/or frequency modulator(s) between optical inputs for light from different quantum network nodes and a photon arrival detector are used to synchronize light from the different quantum network nodes

Methodology Applied

Scientific EffectOptical phase modulation: Phase Modulation

Implementation Method 2

Methodology Applied

Scientific EffectOptical frequency modulation: Phase Modulation

Implementation Method 3

optical frequency converters at the nodes to convert photon wavelengths to standard communication fiber frequencies

Methodology Applied

Scientific EffectFrequency conversion:

Data Source

PatentEP3891908B1Photon exchange based quantum network and method of operating such a network

Publication Date: 2022.11.23 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO

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Figure 3
Figure 3a

AI summary

Quantum network nodes use light from a laser to stimulate emission of single photons. A detection station detects arrival of the photons from the quantum network nodes at a photon arrival detector. In time slots between single photon emissions, the quantum network node supply light from the laser to the detection station. The detection station measures a phase differences between light from a reference laser and the light received from different quantum network nodes in said time slots. The detection station has optical phase and/or frequency modulators between the optical inputs for light from the quantum network nodes and the photon arrival detector. The detection station uses the measured phase differences in control loops to control the phase or frequency modulator to adjust modulation dependent on the phase difference, so as to establish a predetermined phase relation between the reference laser and the light obtained by modulating the received light from the quantum network nodes in the detection station. The control signal is maintained during the expected time of arrival of photons emitted by the quantum network nodes.