Superconducting Phase-Shift System Using SQUID Inductance
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Solution Overview
Problem
Existing superconducting digital technologies face challenges in scaling due to the need for precise signal manipulation in cryogenic environments, where variable phase shift devices like varactors require control voltages that are difficult to generate with single flux quantum (SFQ) circuits.
Innovation Solution
A superconducting phase-shift system utilizing an all-pass filter with variable inductance elements, such as Superconducting Quantum Interference Devices (SQUIDs), that are controlled by a phase-control current to achieve phase-shifting of input signals, allowing for compact and efficient phase manipulation within cryogenic systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If voltage variable capacitors (varactors) are used for phase shifting, then phase control capability is achieved, but control voltage requirements (1-10 volts) cannot be easily generated by single flux quantum (SFQ) circuits
Solution Approach 1:
The patent changes the control parameter from voltage to current. Instead of using voltage-controlled varactors that require 1-10 volts, the invention uses current-controlled variable inductance elements that can be driven by low-voltage SFQ circuits. This parameter transformation resolves the contradiction by maintaining phase control capability while eliminating the need for high control voltages that are incompatible with SFQ circuits.
Solution Approach 2:
The patent substitutes voltage-controlled capacitive elements with current-controlled inductive elements. This substitution replaces the voltage control mechanism with a current control mechanism, allowing direct integration with SFQ circuits that naturally produce current signals rather than high voltage signals.
2Ease of operation
If distributed elements are used for phase shifting, then phase manipulation is achieved, but device area and complexity increase
Solution Approach 1:
The patent transforms the phase shifting mechanism from distributed capacitive elements to lumped variable inductance elements. This allows the use of compact, discrete components instead of extended distributed structures, significantly reducing the device area while maintaining phase manipulation capability through current-controlled inductance variation.
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 enables effective phase-shifting of signals with variable inductance, providing a compact and efficient means to control signal phases in superconducting circuits, overcoming the limitations of traditional phase-shift systems that rely on distributed elements or high control voltages.
Implementation Method 1
The phase-control current can be inductively coupled to each of the at least one SQUID in each of the at least one variable inductance element
Implementation Method 2
Each of the at least one variable inductance element can be configured as at least one Superconducting Quantum Interference Device (SQUID) each comprising a pair of Josephson junctions
Implementation Method 3
Superconducting digital technology has provided computing and/or communications resources that benefit from unprecedented high speed, low power dissipation, and low operating temperature
Data Source
AI summary
One example includes a superconducting phase-shift system. The system includes an all-pass filter comprising at least one variable inductance element. The all-pass filter can be configured to receive an input signal and to provide the input signal as an output signal that is phase-shifted relative to the input signal based on a variable inductance provided by each of the at least one variable inductance element. The system can further include a phase controller configured to provide a phase-control current to control the variable inductance of the at least one variable inductance element based on a characteristic of the phase-control current.