Planar Waveguide Slow-Mode Section for Single Photon Coupling

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Solution Overview

Problem

Current systems for generating and processing single photons suffer from low coupling efficiency, making it difficult to achieve high-performance quantum simulations and cryptography, as they typically have efficiencies below 10% when coupling single photons from a source to an optical fibre.

Innovation Solution

An optical device comprising a single-photon device coupled to a planar waveguide with a nanostructured section that includes a slow-mode section to enhance light-matter coupling and suppress spontaneous emission, combined with a fibre coupler to efficiently couple photons into an optical fibre, achieving efficiencies greater than 90%.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional coupling methods are used to transfer single photons from source to optical fibre, then the system structure is simple, but the coupling efficiency is low (below 10%)

Engineering Contradiction:

Improvecoupling efficiencyVSAvoidsystem structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A planar waveguide is introduced as an intermediary component between the single-photon source and the optical fibre. The waveguide with its nanostructured section mediates the coupling process, enabling efficient photon transfer while maintaining a relatively compact system architecture.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a slow-mode section in the planar waveguide that changes the propagation parameters of light. By creating a region with modified refractive index properties, the photon density is enhanced and coupling efficiency is dramatically improved, achieving over 90% efficiency.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If high coupling efficiency (>90%) is achieved using planar waveguide with slow-mode section, then single photon generation efficiency is dramatically improved, but the device structure becomes more complex

Engineering Contradiction:

Improvesingle photon generation efficiencyVSAvoidwaveguide structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The planar waveguide is segmented into distinct functional sections: a standard waveguide section, a nanostructured slow-mode section, and a coupling section. This segmentation allows each part to be optimized for its specific function while maintaining overall system manageability and manufacturability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The nanostructured section is localized to a specific region of the planar waveguide where it is needed for enhancing light-matter interaction. The surrounding waveguide structure maintains its simple, standard design, thus achieving high productivity only where necessary while minimizing overall complexity.

Inventive Principle:

Principle #3Local quality

3Reliability

If near-unity coupling efficiency is achieved, then the probability of creating useful photonic state increases significantly, but manufacturing precision requirements increase

Engineering Contradiction:

Improveprobability of creating useful photonic stateVSAvoidnanostructure fabrication precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The nanostructured waveguide section is designed to be self-aligning with the single-photon source through epitaxial growth processes. The quantum dot source is integrated directly into the waveguide structure during fabrication, eliminating the need for precise post-fabrication alignment and reducing manufacturing precision requirements.

Inventive Principle:

Principle #25Self-service

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 highly efficient generation and control of single photons, with the potential for near-unity coupling efficiency, significantly improving the performance of quantum simulations and cryptography systems.

Implementation Method 1

a slow-mode section, in which the single-photon device is positioned or embedded

Methodology Applied

Scientific EffectSlow light:

Implementation Method 2

the first nanostructure and second nanostructure suppress spontaneous emission into other modes

Methodology Applied

Scientific EffectPurcell effect:

Implementation Method 3

a planar waveguide with a nanostructured section that includes: a longitudinal extending guiding region

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 4

a fibre coupler for coupling light out of the planar waveguide and into an optical fibre

Methodology Applied

Scientific EffectMode matching:

Data Source

PatentUS9798083B2Optical device having efficient light-matter interface for quantum simulations

Publication Date: 2017.10.24 UNIVERSITY OF COPENHAGEN

AI summary

An optical device comprising a single-photon device, which is coupled to a planar waveguide is described. The planar waveguide comprises a nanostructured section, which includes a longitudinal extending guiding region with a first side and a second side, a first nanostructure arranged on the first side of the guiding region, and a second nanostructure arranged on the second side of the guiding region. The nanostructured section comprises a slow-mode section, in which the single-photon device is positioned or embedded, and in which the first nanostructure and second nanostructure suppress spontaneous emission into other modes. The planar waveguide further comprises a fiber coupler for coupling light out of the planar waveguide and into an optical fiber, the fiber coupler preferably being adapted to match a field profile of an optical fiber.