Cascaded Resonator Photon Pair Source for Purity-Brightness Tradeoff
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Solution Overview
Problem
Existing photon pair sources face challenges in achieving high spectral purity and brightness due to the tradeoff between resonance bandwidth and frequency alignment, which limits their applicability in applications like quantum computing and quantum communications.
Innovation Solution
The use of cascaded resonators on a single bus waveguide, where multiple optical resonators with different resonant frequencies are coherently combined, allowing for enhanced spectral purity and brightness while decoupling bandwidth from source brightness, and enabling the production of identical photons despite resonance shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple optical resonators with different resonant frequencies are used to increase brightness, then spectral purity deteriorates due to frequency misalignment
Solution Approach 1:
Multiple optical resonators with different resonant frequencies are merged onto a single bus waveguide to create a cascaded resonator system. This combining approach increases the overall brightness by aggregating the output of multiple resonators while maintaining spectral purity through coherent combination, resolving the contradiction between brightness and spectral purity.
Solution Approach 2:
The system changes the resonant frequency parameter across multiple resonators, with each resonator having a different resonant frequency that is intentionally mismatched relative to the pump laser. This parameter variation allows the system to overcome frequency alignment issues and achieve both high brightness and spectral purity simultaneously.
2Manufacturing precision
If resonance bandwidth is narrowed to improve spectral purity, then brightness decreases due to reduced pump laser coupling
Solution Approach 1:
The system segments the photon generation function across multiple resonators instead of relying on a single resonator with narrow bandwidth. Each resonator can have broader bandwidth for better pump coupling, and the collective output of multiple segmented resonators achieves the desired spectral purity through their combined response.
Solution Approach 2:
Multiple resonators with broader individual bandwidths are merged onto a single bus waveguide. The combining of their outputs achieves the effective spectral filtering that would require narrow bandwidth in a single resonator, while maintaining better pump laser coupling efficiency.
3Productivity
If resonant frequencies are precisely aligned with pump laser to maximize efficiency, then the system becomes sensitive to manufacturing variations
Solution Approach 1:
Instead of precise frequency alignment, the system intentionally uses resonant frequencies that are mismatched relative to the pump laser. This parameter change makes the system robust to manufacturing variations because the broader frequency acceptance reduces sensitivity to frequency drift and fabrication tolerances.
Solution Approach 2:
The cascaded resonator system self-adjusts to pump frequency variations through the collective response of multiple resonators with different resonant frequencies. The system inherently compensates for manufacturing variations without requiring external tuning or alignment, achieving reliable operation across production tolerances.
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 results in high spectral purity (>99%) and increased brightness, making the photon pair source robust to manufacturing variations and allowing for reduced trimming and tuning requirements, while also enabling the production of Gaussian photons and efficient pump recycling.
Implementation Method 1
Each optical resonator of the plurality of optical resonators can have a respective resonance line width and a respective resonance frequency
Implementation Method 2
spontaneous four wave mixing (SFWM) or spontaneous parametric down-conversion (SPDC)
Implementation Method 3
spontaneous four wave mixing (SFWM) or spontaneous parametric down-conversion (SPDC)
Implementation Method 4
a plurality of dispersive elements coupled to the bus waveguide, wherein one dispersive element of the plurality of dispersive elements is positioned in-between each adjacent pair of optical resonators
Data Source
AI summary
A photon source includes a bus waveguide, a photon source pump laser coupled to the bus waveguide and a plurality of optical resonators coupled to the bus waveguide. Each optical resonator of the plurality of optical resonators has a respective resonance line width and a respective resonance frequency, wherein a bandwidth of the resonant center frequencies of the plurality of optical resonators is greater than a bandwidth of the photon source pump laser. The bus waveguide produces photons in response to receiving laser pulses from the pump laser.