Oscillator Reflection Calibration for Quantum Annealing Signal Loss
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Solution Overview
Problem
The challenge is to accurately supply an appropriate power signal to a quantum annealing circuit's oscillator, as the power loss from the signal generator to the oscillator is unknown, making it difficult to set the desired coupling intensities between quantum bits for solving combinatorial optimization problems.
Innovation Solution
A calibration method that involves outputting an input signal to a superconducting resonator oscillator, sweeping its frequency or power, measuring the reflection signal intensity, and estimating signal loss by comparing measured data with theoretically obtained data, using a calibration apparatus with a signal controller, measurement unit, and estimation unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coaxial cable and circulator are interposed between the signal generator and the oscillator input node, then the signal can be transmitted from room temperature to extremely low temperature, but power loss is generated in the input signal
Solution Approach 1:
The patent introduces a circulator as an intermediary device between the signal generator and the oscillator. The circulator enables bidirectional signal transmission (forward and reflection signals) while isolating the signal generator from direct connection to the cold environment, thus maintaining signal transmission capability while minimizing power loss in the transmission path.
2Device complexity
If the power loss amount is unknown, then the system configuration is simple, but it is difficult to accurately supply an input signal with appropriate power to the input node
Solution Approach 1:
The patent implements a feedback mechanism by measuring the reflection signal from the oscillator and using this information to calculate the actual power delivered to the input node. The calibration apparatus measures the reflection signal intensity, compares it with theoretical values, and determines the power loss in the transmission path, thereby enabling accurate power supply control.
Solution Approach 2:
The patent performs preliminary calibration measurements to determine the power loss characteristics of the transmission path before actual operation. By pre-measuring the reflection signal and calculating the power loss, the system establishes a reference for accurate power supply without requiring complex real-time adjustments during operation.
3Measurement precision
If the reflection signal is measured to perform calibration, then the power supply accuracy can be improved, but the measurement and calibration process becomes more complex
Solution Approach 1:
The calibration apparatus uses the oscillator's own reflection signal to perform the calibration measurement. By measuring the reflection signal that naturally occurs when the input signal is applied to the oscillator, the system performs self-calibration without requiring additional external calibration equipment or complex external measurement setups.
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 method allows for accurate estimation of signal loss, enabling the precise supply of input signal power to the oscillator, thereby improving the accuracy of setting coupling intensities in the quantum annealing circuit for solving optimization problems.
Implementation Method 1
an oscillator to be calibrated that includes a resonator, which is a superconducting circuit, and performs parametric oscillation
Data Source
AI summary
A calibration method, a calibration apparatus, and a program capable of estimating a degree of signal loss of an input signal supplied to an oscillator are provided. The calibration method includes: outputting an input signal to be input to an oscillator to be calibrated that includes a resonator and performs parametric oscillation, from a signal generator connected to the resonator via a transmission path while sweeping a frequency or a power of this input signal; acquiring distribution data of an intensity of a reflection signal based on measurement of the intensity of the reflection signal from the oscillator in response to the input signal; and estimating a degree of signal loss by comparing the distribution data acquired by the measurement with the distribution data theoretically obtained in which a value of the degree of the signal loss of the transmission path is assumed.