Dual-Sideband Microwave Interferometer for Quantum Readout Noise Suppression
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Solution Overview
Problem
Current interferometry technologies for quantum computing are susceptible to systematic noise, particularly common mode phase and amplitude noise, which complicates the measurement readout of radio frequency signals and affects the coherence of qubits, making it difficult to determine noise origins and access quality factors of devices under test.
Innovation Solution
The implementation of an interferometer device that detects the interference of two spectral sidebands, allowing for the suppression of common mode phase or amplitude noise and enabling the measurement of qubit states or parity of qubits by employing one sideband as a reference to the other, which is affected by the device under test, thereby reducing decoherence and improving measurement resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single sideband measurement is used, then device complexity is reduced, but measurement precision deteriorates due to sensitivity to common mode phase noise and amplitude noise
Solution Approach 1:
The measurement system segments the microwave signal into two distinct spectral sidebands (first sideband at frequency f1 and second sideband at frequency f2) that are processed independently through separate measurement paths. This segmentation allows each sideband to be measured separately, enabling the system to distinguish between signals affected by the device under test and those affected by common mode noise, thereby resolving the contradiction between system simplicity and measurement precision.
Solution Approach 2:
The patent introduces an interferometer as an intermediary component that combines the first and second sidebands in a controlled manner. The interferometer acts as a mediator that enables differential measurement by comparing the two sidebands, allowing the system to suppress common mode noise while maintaining measurement precision without requiring overly complex measurement infrastructure.
2Measurement precision
If dual sideband interferometry is implemented, then measurement precision is improved through noise suppression, but device complexity increases
Solution Approach 1:
The patent merges the measurement of two spectral sidebands into a unified interferometric measurement system. By combining the first sideband (affected by the device under test) and the second sideband (reference) through the interferometer, the system achieves noise suppression while consolidating complexity into a single integrated measurement apparatus rather than requiring separate complex measurement systems for each sideband.
Solution Approach 2:
The interferometer serves multiple functions simultaneously: it acts as a signal combiner, a noise suppressor, and a differential measurement device. This multi-functionality allows the system to achieve high measurement precision through noise suppression while avoiding the need for multiple separate specialized devices, thereby managing device complexity effectively.
3Ease of operation
If common mode noise is present in single sideband measurement, then measurement readout is simplified, but reliability deteriorates due to inability to distinguish noise from signal
Solution Approach 1:
The patent implements a feedback mechanism where the second sideband (reference sideband) provides continuous information about the common mode noise conditions. This feedback allows the measurement system to compensate for and distinguish common mode noise from the actual signal, improving reliability while maintaining ease of operation through automated noise correction rather than complex manual analysis.
Solution Approach 2:
The interferometer serves as an intermediary that enables reliable noise discrimination by creating a controlled environment where the first and second sidebands interact. This intermediary device allows the system to distinguish between signal components affected by the device under test and common mode noise, improving reliability without complicating the measurement readout process.
4Reliability
If dual sideband measurement is used, then reliability is improved through noise suppression, but measurement precision requirements increase
Solution Approach 1:
The patent utilizes parameter changes in the interferometer settings, particularly adjusting the phase and amplitude relationships between the two sidebands. By dynamically adjusting these parameters, the system can optimize the interference pattern to enhance noise suppression while maintaining measurement precision, allowing reliable measurements without requiring excessively high precision in all measurement components.
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 provides quantum-limited readout of relative phase or amplitude changes, making measurements insensitive to systematic uncertainties and allowing simultaneous access to resonance frequency and quality factor variations, leading to more stable and efficient qubit state measurements.
Implementation Method 1
an interferometer device that detects an interference of two spectral sidebands
Implementation Method 2
an IQ modulator that generates the two spectral sidebands using a local oscillator (LO) microwave signal and a pair of signals at a same intermediate frequency
Implementation Method 3
a mixer that mixes the two sidebands with a local oscillator (LO) microwave signal and thereby interferes the two sidebands
Implementation Method 4
the two spectral sidebands can comprise a first sideband that has been at least partially absorbed or phase-shifted and reflected or transmitted by a test device and a second sideband that has been reflected off or transmitted by the test device
Data Source
AI summary
One or more systems, devices and/or methods of use provided herein relate to a device that can facilitate a process to measure a pair of spectral sidebands and suppress one of common mode phase or amplitude noise. A device can comprise an interferometer device that can detect an interference of two spectral sidebands. The interferometer device can comprise a signal circuit that can detect at least one of a phase or an amplitude of a signal resulting from the interference of the two spectral sidebands, an IQ modulator that can generate the two spectral sidebands using a portion of a local oscillator (LO) microwave signal and a pair of signals at a same intermediate frequency, and/or a mixer that can interfere the two spectral sidebands having been output or reflected from a device under test, including mixing the two spectral sidebands with another portion of the LO microwave signal.