Multiplexed Single-Photon Generator With Optical Switching
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Solution Overview
Problem
Existing single-photon sources have limitations in photon generation rate and efficiency, and there is a need for a solution that can enhance the generation of single photons in a controlled and efficient manner, particularly for applications in quantum computing and quantum communication.
Innovation Solution
A multiplexed single-photon generator is developed, combining multiple single-photon sources on a photonic integrated circuit (PIC) with an optical switching network and a bus waveguide, allowing for time- or frequency-multiplexed operation to increase the photon generation rate and efficiency, and incorporating quantum emitters within photonic crystal cavities to enhance spontaneous decay and collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple single-photon sources are combined into a multiplexed generator, then the photon generation rate increases, but the device complexity increases
Solution Approach 1:
Multiple single-photon sources are merged into a single multiplexed generator platform, where multiple quantum emitters are integrated on a common photonic chip with shared optical components (bus waveguide, optical switching network, pump laser), enabling high-rate photon generation while managing complexity through consolidation
Solution Approach 2:
The system segments the photon generation function across multiple independent single-photon sources (multiple quantum emitters), each operating independently but contributing to a unified high-rate output stream through temporal or frequency multiplexing
2Reliability
If time-multiplexed operation is used to ensure photon distinguishability, then the photon stream quality improves, but the photon generation rate is limited by sequential operation
Solution Approach 1:
The system employs periodic action through time-multiplexed pumping of multiple quantum emitters, where each emitter is excited in sequence at optimized time intervals, ensuring that photons are emitted at distinct times without temporal overlap, thus maintaining indistinguishability and stream quality
Solution Approach 2:
The system transitions from temporal multiplexing to frequency multiplexing, where multiple quantum emitters are excited simultaneously but emit photons at different optical frequencies. This dimensional change allows parallel operation (improving rate) while maintaining photon distinguishability through frequency tagging rather than temporal separation
3Productivity
If frequency-multiplexed operation is used to increase photon generation rate, then the productivity improves, but the photons become distinguishable by frequency
Solution Approach 1:
The system exploits the frequency dimension to multiplex multiple single-photon sources simultaneously, allowing parallel operation and high photon generation rates. Frequency distinguishability is managed through post-processing or application-specific requirements, enabling productivity improvement while accepting frequency as a distinguishable parameter
4Reliability
If photonic crystal cavities are used to enhance spontaneous decay, then the collection efficiency improves, but the manufacturing precision requirements increase
Solution Approach 1:
The system optimizes the photonic crystal cavity parameters (hole size, spacing, depth) to achieve the desired spontaneous decay enhancement and collection efficiency. By carefully tuning these geometric parameters during fabrication, the system achieves high performance while managing the inherent precision requirements through design optimization
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 multiplexed generator achieves a higher photon generation rate and efficiency by ensuring temporal or frequency distinguishability of photons, enabling applications in quantum computing and communication systems.
Implementation Method 1
Each of the plurality of single-photon sources includes an optical cavity and a quantum emitter coupled to the optical cavity
Implementation Method 2
an optical switching network controllable to couple pump light into the optical cavity of any one of the plurality of single-photon sources
Implementation Method 3
a bus waveguide coupled to the optical cavity of each of the plurality of single-photon sources so that all of the single photons emitted by all of the single-photon sources propagate in the same direction down the bus waveguide
Data Source
AI summary
A multiplexed single-photon generator includes a plurality of single-photon sources, an optical switching network controllable to couple pump light into any one of the single-photon sources, and a bus waveguide optical coupled to all of the single-photon sources. Each single-photon source includes a quantum emitter coupled to an optical cavity. All of the single photons emitted by all of the single-photon sources propagate along the bus waveguide. The single-photon generator may be time-multiplexed in which only one of the single-photon sources is pumped at any time. In this case, the single photons form a temporal sequence with little or no temporal overlap. As an alternative to time multiplexing, the single-photon generator may be frequency-multiplexed such that each single-photon source emits single photons that are distinguishable from the other emitted single photons based on optical frequency.