Single-Photon Waveguide Device for High Coupling Efficiency
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Solution Overview
Problem
Existing single-photon devices face challenges in achieving high coupling efficiency and mechanical stability for generating and outputting coherent single photons, particularly for commercial use and integration with optical fibers.
Innovation Solution
The optical device comprises a first filter waveguide section that couples pump signal power predominantly into a higher-order guided mode of an emitter waveguide section, where a photon emitter emits radiation into a lower-order mode. A second filter waveguide section is configured to transmit radiation in the lower-order mode with lower loss than other modes, ensuring efficient out-coupling of single photons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art systems use quantum dots in waveguides for single-photon generation, then single photons can be produced, but coupling efficiency into optical fibers is low
Solution Approach 1:
The device is divided into three distinct waveguide sections: a first filter section that prepares the pump signal, an emitter section that generates single photons, and a second filter section that outputs purified single photons. This segmentation allows each section to be optimized for its specific function, achieving high coupling efficiency while maintaining high productivity.
Solution Approach 2:
The patent uses higher-order waveguide modes as intermediaries to transfer energy between different components. The pump signal is coupled into higher-order modes in the first filter section, which then couple to the quantum dot in the emitter section, and finally single photons are extracted through higher-order modes in the second filter section. This intermediary mechanism enables efficient coupling throughout the system.
2Reliability
If prior art systems mechanically couple single-photon devices to optical fibers, then photon output is achieved, but mechanical stability is insufficient for commercial use
Solution Approach 1:
The patent merges the single-photon source with the coupling mechanism by integrating optical fibers directly into the waveguide structure. The fibers are positioned to receive higher-order modes directly from the emitter waveguide section, creating a unified, mechanically stable assembly that eliminates separate coupling components and simplifies manufacturing.
3Productivity
If pump signal power is coupled into multiple waveguide modes, then pumping efficiency is improved, but single-photon purity is reduced due to mode mixing
Solution Approach 1:
Different sections of the waveguide are designed with different modal properties. The first filter section is optimized to support and propagate higher-order modes for efficient pumping, while the emitter section creates localized coupling to the quantum dot, and the second filter section is designed to suppress higher-order modes and transmit only the fundamental single-photon mode. This local optimization of modal quality ensures both pumping efficiency and photon purity.
4Reliability
If higher-order waveguide modes are used for pump coupling, then coupling efficiency is enhanced, but mechanical alignment precision requirements increase
Solution Approach 1:
The first filter waveguide section is designed to pre-condition the pump signal by coupling it into higher-order modes before the signal reaches the emitter section. This preliminary action ensures that the pump power is already in the correct modal form when it reaches the quantum dot, eliminating the need for precise alignment at the critical emitter-fiber interface and reducing manufacturing precision requirements.
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 configuration enables highly efficient generation and output of indistinguishable single photons with improved mechanical stability, overcoming the limitations of prior art systems by enhancing coupling efficiency and reliability.
Implementation Method 1
the first filter waveguide section being configured to couple pump signal power predominantly into the second guided mode of the emitter section
Implementation Method 2
a photon emitter coupled to the first guided mode to emit radiation into the first guided mode
Implementation Method 3
the second filter waveguide section being configured to transmit radiation emitted into the first guided mode with lower loss than radiation emitted into modes other than the first guided mode
Data Source
AI summary
This disclosure relates to an optical device comprising: a first filter waveguide section having an input for receiving a pump signal, the first filter waveguide section further having an output; an emitter waveguide section having an input coupled to the output of the first filter waveguide section to receive a transmitted pump signal therefrom, the emitter waveguide section supporting at least a first guided lower-order optical mode and a second guided higher-order optical mode, the emitter waveguide section comprising a photon emitter coupled to the first guided mode to emit radiation into the first guided mode and coupled to the second guided mode to allow optical pumping of the photon emitter by pump signal power carried in the second guided mode, the emitter waveguide section further having an output for outputting radiation emitted from the photon emitter; a second filter waveguide section having an input coupled to the output of the emitter waveguide section and having an output, the second filter waveguide section being configured to transmit radiation emitted into the first guided mode with lower loss than radiation emitted into modes other than the first guided mode; the first filter waveguide section being configured to couple pump signal power predominantly into the second guided mode of the emitter section.