3 research outputs found
CMOS-based cryogenic control of silicon quantum circuits
The most promising quantum algorithms require quantum processors hosting
millions of quantum bits when targeting practical applications. A major
challenge towards large-scale quantum computation is the interconnect
complexity. In current solid-state qubit implementations, a major bottleneck
appears between the quantum chip in a dilution refrigerator and the room
temperature electronics. Advanced lithography supports the fabrication of both
CMOS control electronics and qubits in silicon. When the electronics are
designed to operate at cryogenic temperatures, it can ultimately be integrated
with the qubits on the same die or package, overcoming the wiring bottleneck.
Here we report a cryogenic CMOS control chip operating at 3K, which outputs
tailored microwave bursts to drive silicon quantum bits cooled to 20mK. We
first benchmark the control chip and find electrical performance consistent
with 99.99% fidelity qubit operations, assuming ideal qubits. Next, we use it
to coherently control actual silicon spin qubits and find that the cryogenic
control chip achieves the same fidelity as commercial instruments. Furthermore,
we highlight the extensive capabilities of the control chip by programming a
number of benchmarking protocols as well as the Deutsch-Josza algorithm on a
two-qubit quantum processor. These results open up the path towards a fully
integrated, scalable silicon-based quantum computer
A Scalable Cryo-CMOS Controller for the Wideband Frequency-Multiplexed Control of Spin Qubits and Transmons
Building a large-scale quantum computer requires the co-optimization of both the quantum bits (qubits) and their control electronics. By operating the CMOS control circuits at cryogenic temperatures (cryo-CMOS), and hence in close proximity to the cryogenic solid-state qubits, a compact quantum-computing system can be achieved, thus promising scalability to the large number of qubits required in a practical application. This work presents a cryo-CMOS microwave signal generator for frequency-multiplexed control of 4 x 32 qubits (32 qubits per RF output). A digitally intensive architecture offering full programmability of phase, amplitude, and frequency of the output microwave pulses and a wideband RF front end operating from 2 to 20 GHz allow targeting both spin qubits and transmons. The controller comprises a qubit-phase-tracking direct digital synthesis (DDS) back end for coherent qubit control and a single-sideband (SSB) RF front end optimized for minimum leakage between the qubit channels. Fabricated in Intel 22-nm FinFET technology, it achieves a 48-dB SNR and 45-dB spurious-free dynamic range (SFDR) in a 1-GHz data bandwidth when operating at 3 K, thus enabling high-fidelity qubit control. By exploiting the on-chip 4096-instruction memory, the capability to translate quantum algorithms to microwave signals has been demonstrated by coherently controlling a spin qubit at both 14 and 18 GHz