Low Noise Design

In superconducting qubit systems, the XY line is used for gate control, while the readout line drives and measures the resonator. Microwave phase noise on these paths directly affects the accuracy of qubit manipulation and measurement. For XY control, excessive phase noise introduces random phase fluctuations that reduce gate fidelity. For readout, poor phase noise degrades signal stability and state discrimination, reducing measurement consistency.

Power Quantum uses an excellent reference clock source together with a carefully engineered clock distribution network to tightly control noise and jitter across the full signal chain. Through optimization of synchronization and microwave generation paths, the output phase noise fully supports qubit fidelity requirements at the 99.99% level, providing a solid foundation for high-quality control, stable readout, and fast feedback operation.

As quantum systems scale toward more channels and more complex experiments, microwave signal purity becomes increasingly important. A low-noise microwave source helps maintain repeatable gate calibration, cleaner qubit rotations, and more reliable readout discrimination under multi-channel synchronized operation.

Our quantum measurement and control system maintains an ultra-low output noise spectral density as low as -160 dBm/Hz for both XY drive lines and readout lines, even at maximum output power. This exceptional noise performance suppresses residual thermal and spurious perturbations, effectively avoiding decoherence induced noise coupling and preserving the intrinsic T1 lifetime of qubits without measurable degradation.

In qubit systems, baseband noise on the Z-line couples directly to the qubits, thereby inducing decoherence. To address this, Power Quantum employs high-performance, low-noise DACs—combined with deeply optimized designs for clock synchronization, power delivery, and channel isolation—to deliver a system-level noise reduction solution. Its normalized baseband output noise performance is exceptional: at an output amplitude of 1 Vpp, the integrated noise within the 1 Hz to 1 MHz frequency band is an extremely low 10 µVrms, achieving maximum noise suppression from the very foundation of the analog circuitry.

Low-frequency noise introduced via the Z-line increases the phase uncertainty of quantum states, causing an accelerated decay of Ramsey interference fringes and severely limiting the T2* coherence time. Leveraging its ultra-low noise characteristics, Power Quantum minimizes the interference of measurement and control electronics with qubit states, thereby significantly delaying the decay of Ramsey interference fringes. This profound optimization of coherence performance powerfully enables users to perfectly preserve and harness the inherent, superior performance of quantum devices in applications such as frequency calibration, long-coherence experiments, and precision magnetic flux control.