Cascaded Optical Resonators for Spectrally Pure Photon Pair Generation
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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 substantially identical photons despite resonance frequency shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single optical resonator is used to generate photon pairs, then the device complexity is low, but the spectral purity and brightness are limited due to the tradeoff between resonance bandwidth and frequency alignment
Solution Approach 1:
The single resonator is segmented into multiple cascaded resonators, each with different resonant frequencies. This segmentation allows the system to achieve high spectral purity through coherent combination of multiple resonances while maintaining manageable device complexity through modular integration on a bus waveguide.
Solution Approach 2:
Multiple resonators are merged into a cascaded system where their output fields interfere constructively. The merging of multiple resonance modes with different frequencies creates a combined spectral profile that achieves both high purity and broadband operation, resolving the tradeoff between simplicity and performance.
2Manufacturing precision
If multiple optical resonators with different resonant frequencies are used, then the spectral purity and brightness are enhanced, but the device complexity increases
Solution Approach 1:
The system transitions from a single-frequency resonator to a multi-frequency cascaded system, adding the dimension of frequency diversity. This dimensional expansion allows simultaneous achievement of high spectral purity at multiple frequencies while maintaining a compact integrated structure on the bus waveguide.
Solution Approach 2:
The cascaded resonator system serves multiple functions: it generates photon pairs with high spectral purity, achieves broadband operation, and provides robustness to manufacturing variations. The universal design accommodates different resonant frequencies while maintaining a unified integrated structure, reducing the impact of increased complexity.
3Manufacturing precision
If the resonance frequency of a single resonator is precisely aligned, then the spectral purity is high, but the system is sensitive to manufacturing variations and requires trimming and tuning
Solution Approach 1:
Each resonator in the cascade is designed with a specific local resonant frequency, creating a distribution of frequencies across the system. This local quality differentiation ensures that manufacturing variations affecting individual resonators do not collectively degrade the overall spectral purity, as the coherent combination averages out local deviations.
Solution Approach 2:
The system uses multiple copies of resonator structures with deliberately different resonant frequencies. This copying approach with frequency differentiation creates redundancy, where the overall system performance is maintained even if individual resonators deviate from their design frequencies due to manufacturing variations.
4Productivity
If the bandwidth of the pump laser is increased to cover multiple resonant frequencies, then the brightness is improved, but the spectral purity decreases
Solution Approach 1:
The system dynamically exploits the coherent interaction between the pump laser and multiple resonators with different frequencies. By tuning the pump laser to resonate with the cascaded system, the brightness is enhanced through constructive interference while the spectral purity is maintained through the selective enhancement of specific frequency components in the photon pair generation process.
Solution Approach 2:
The optical system creates a composite resonance structure where multiple resonators with different frequencies work together. This composite resonant system allows the pump laser to couple to multiple modes simultaneously, achieving high brightness through broadband coupling while maintaining spectral purity through the coherent combination of resonant fields that selectively enhance the desired photon pair frequencies.
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 and increased brightness, making the photon pair sources robust to manufacturing variations and allowing for improved performance in applications such as quantum computing and quantum communications, with reduced need for frequency alignment trimming and tuning.
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
multiple optical resonators with different resonant frequencies are coherently combined, allowing for enhanced spectral purity and brightness
Implementation Method 3
a bus waveguide, a pump laser coupled to the bus waveguide
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 frequency conversion system includes a bus waveguide, a first pump laser coupled to the bus waveguide and characterized by a first frequency, a second pump laser coupled to the bus waveguide and characterized by a second frequency, an input light combining device coupled to the bus waveguide and configured to combine light from the first pump laser and the second pump laser to produce a combined light, 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, wherein for each optical resonators of the plurality the respective resonance line width overlaps with a resonance line width of at least one adjacent optical resonator of the plurality of optical resonators, and wherein each optical resonator of the plurality is configured to generate output light at a converted frequency via frequency mixing.