Cascading Josephson Isolators for Frequency Multiplexed Signals
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Solution Overview
Problem
Current microwave isolators in quantum computing are limited in their ability to selectively isolate frequency-multiplexed microwave signals, as they typically operate within narrow bandwidths and cannot effectively handle signals outside their operational frequency range, leading to inefficiencies in signal propagation and isolation.
Innovation Solution
The implementation of cascading multi-path interferometric Josephson isolators with nonoverlapping bandwidths, based on nondegenerate three-wave-mixing Josephson devices, allows for the selective isolation and propagation of microwave signals across a broader frequency range by configuring each isolator to operate within its specific bandwidth, enabling both lossless signal passing and isolation depending on frequency direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single microwave isolator is used, then it provides isolation within its operational bandwidth, but it cannot effectively handle signals outside its narrow frequency range
Solution Approach 1:
The system divides the frequency isolation task into multiple segments by using multiple isolators, each tuned to a specific frequency band. Each isolator handles a portion of the overall frequency range, and their combined effect provides broadband isolation coverage without requiring a single complex isolator design.
Solution Approach 2:
The cascaded isolator system achieves multi-functionality by combining multiple frequency-selective isolators to create a universal isolation solution that covers a broad frequency range. The system can handle multiple frequency bands simultaneously, making it adaptable to various quantum computing signal requirements.
2Adaptability or versatility
If multiple isolators with overlapping bandwidths are used, then broader frequency coverage is achieved, but signal interference and isolation effectiveness deteriorate
Solution Approach 1:
Each isolator in the cascade is designed with specific local quality characteristics tailored to its designated frequency band. The bandwidth and center frequency of each isolator are optimized for its specific operational range, ensuring high isolation effectiveness within that band while avoiding interference with other bands.
Solution Approach 2:
The isolators are configured with asymmetric, nonoverlapping bandwidths where each subsequent isolator's passband is positioned to follow the previous one without overlap. This asymmetric arrangement eliminates signal interference while maintaining continuous broad frequency coverage across the cascade.
3Adaptability or versatility
If isolators with nonoverlapping bandwidths are cascaded, then selective isolation across broad frequency range is achieved, but device complexity increases
Solution Approach 1:
The frequency multiplexing function is segmented across multiple isolators, each responsible for a specific frequency channel. This segmentation allows the system to handle multiple quantum computing signals simultaneously at different frequencies while maintaining simple, standardized isolator designs that can be cascaded modularly.
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 solution enhances the operational bandwidth for both signal propagation and isolation, allowing for efficient handling of frequency-multiplexed signals across a broader range than single isolators, thereby improving the reliability and efficiency of quantum computing processes.
Implementation Method 1
cascading multi-path interferometric josephson isolators
Implementation Method 2
multi-path interferometric josephson isolators
Data Source
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AI summary
A cascading selective microwave isolator includes a set of Josephson devices (110), each Josephson device (110) in the set having a corresponding operating bandwidth of microwave frequencies. Different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device (110) from the set and an nthJosephson device from the set. The series coupling causes the first Josephson device to isolate a signal at a first frequency from a frequency multiplexed microwave signal in a first signal flow direction through the series coupling and the nthJosephson device to isolate a signal of an nthfrequency in a second signal flow direction through the series, where the second signal flow direction is opposite of the first signal flow direction.