Widely Tunable On-Chip Microwave Circulator for Superconducting Quantum Circuits
Benjamin J. Chapman, Eric I. Rosenthal, Joseph Kerckhoff, Bradley A. Moores, Leila R. Vale, J. A. B. Mates, Gene C. Hilton, Kevin Lalumière, Alexandre Blais, K. W. Lehnert
We report on the design and performance of an on-chip microwave circulator with a widely (GHz) tunable operation frequency.Nonreciprocity is created with a combination of frequency conversion and delay, and requires neither permanent magnets nor microwave bias tones, allowing on-chip integration with other superconducting circuits without the need for high-bandwidth control lines.Isolation in the device exceeds 20 dB over a bandwidth of tens of MHz, and its insertion loss is small, reaching as low as 0.9 dB at select operation frequencies.Furthermore, the device is linear with respect to input power for signal powers up to hundreds of fW (≈10 3 circulating photons), and the direction of circulation can be dynamically reconfigured.We demonstrate its operation at a selection of frequencies between 4 and 6 GHz.
We report on the design and performance of an on-chip microwave circulator with a widely (GHz) tunable operation frequency.Nonreciprocity is created with a combination of frequency conversion and delay, and requires neither permanent magnets nor microwave bias tones, allowing on-chip integration with other superconducting circuits without the need for high-bandwidth control lines.Isolation in the device exceeds 20 dB over a bandwidth of tens of MHz, and its insertion loss is small, reaching as low as 0.9 dB at select operation frequencies.Furthermore, the device is linear with respect to input power for signal powers up to hundreds of fW (≈10 3 circulating photons), and the direction of circulation can be dynamically reconfigured.We demonstrate its operation at a selection of frequencies between 4 and 6 GHz.
This thesis develops theory for and experimentally demonstrates a new way to break Lorentz reciprocity—the symmetry, in an electrical network, under exchange of source and detector. The approach is based on the sequential application of frequency conversion and delay; as frequency and time are Fourier duals, these operations do not generally commute. We apply this method in the construction of an on-chip superconducting microwave circulator, a critical component for the unidirectional routing of quantum information in superconducting networks. The device requires neither permanent magnets nor microwave control tones, allowing on-chip integration with other superconducting circuits without expensive control hardware. Isolation in the device exceeds 20 dB over a bandwidth of tens of MHz, and its insertion loss is small, reaching as low as 0.9 dB at select operation frequencies. Furthermore, the device is linear with respect to input power for signal powers up to many hundreds of fW (~103 circulating photons), and the direction of circulation can be dynamically reconfigured. We demonstrate its tunability with operation at a selection of frequencies between 4 and 6 GHz. Given the current status of quantum error-correction and architectures for quantum information processing with superconducting circuits, such scalable non-reciprocal devices will almost certainly be necessary for construction of a superconducting quantum computer intended to be more than a proof-of-principle.
Abstract In quantum information detection, significant interest has recently emerged in replacing conventional ferrite circulators with superconducting magnetic-free nonreciprocal devices. However, superconducting non-reciprocal devices with simpler structures and easier manufacturing processes still require further development. Inspired by conventional microwave circuits, we demonstrate a superconducting nonreciprocal circulator by parametric modulation of three identical, strongly and symmetrically coupled resonators. The circulator requires only three DC superconducting quantum interference devices, achieving an isolation of 20 dB , insertion loss of 0.47 dB , and return loss better than 25 dB over an instantaneous bandwidth of 50 MHz . The center frequency of the circulator is tunable within the range of 4– 8 GHz . Detailed design considerations for the experimental realization of a three-port superconducting circulator are presented, together with simulation results for a four-port circulator. Compared with previously reported superconducting magnetic-free nonreciprocal devices, the proposed circulator features a simpler circuit topology, demonstrating strong potential for scalable superconducting quantum information detection.
Ferrite-free circulators that are passive and readily integratable on a chip are highly sought-after in quantum technologies based on superconducting circuits. In our previous work, we implemented such a circulator using a three-Josephson-junction loop that exhibited unambiguous nonreciprocity and signal circulation, but required junction energies to be within 1 % of design values. This tolerance is tighter than standard junction fabrication methods provide, so we propose and demonstrate a design improvement that relaxes the required junction fabrication precision, allowing for higher device performance and fabrication yield. Specifically, we introduce large direct capacitive couplings between the waveguides, which based on the modeling we describe here, requires less stringent junction fabrication tolerance. We implement the design, and measure enhanced “circulation fidelity” above 97 % , with optimized on-resonance insertion loss of 0.2 dB, isolation of 18 dB, and power reflectance of − 15 dB , in good agreement with model calculations.
There needs a large quantity of microwave devices like circulators, isolators and quantum noise limited amplifier in the development of scalable superconducting quantum computers. Traditional isolators and circulators have huge size and could induce a high thermal dissipation. This paper designs a kind of on-chip Isolator-Circulator-Isolator (ICI), which is able to act as isolator and circulator synchronous. The ICI is composed of tunable inductor bridge which based on an array of superconducting quantum interference devices (SQUID). It works on the frequency between 4 and 8 GHz, and operation temperature at 20 mK, with isolation exceeds 40 dB and insertion loss less than 3 dB.
Abstract Nonreciprocal circuit elements form an integral part of modern measurement and communication systems. Mathematically they require breaking of time-reversal symmetry, typically achieved using magnetic materials and more recently using the quantum Hall effect, parametric permittivity modulation or Josephson nonlinearities. Here we demonstrate an on-chip magnetic-free circulator based on reservoir-engineered electromechanic interactions. Directional circulation is achieved with controlled phase-sensitive interference of six distinct electro-mechanical signal conversion paths. The presented circulator is compact, its silicon-on-insulator platform is compatible with both superconducting qubits and silicon photonics, and its noise performance is close to the quantum limit. With a high dynamic range, a tunable bandwidth of up to 30 MHz and an in situ reconfigurability as beam splitter or wavelength converter, it could pave the way for superconducting qubit processors with multiplexed on-chip signal processing and readout.
Nonreciprocal circuit elements form an integral part of modern measurement and communication systems. Mathematically they require breaking of time-reversal symmetry, typically achieved using magnetic materials and more recently using the quantum Hall effect, parametric permittivity modulation or Josephson nonlinearities. Here we demonstrate an on-chip magnetic-free circulator based on reservoir-engineered electromechanic interactions. Directional circulation is achieved with controlled phase-sensitive interference of six distinct electro-mechanical signal conversion paths. The presented circulator is compact, its silicon-on-insulator platform is compatible with both superconducting qubits and silicon photonics, and its noise performance is close to the quantum limit. With a high dynamic range, a tunable bandwidth of up to 30 MHz and an in situ reconfigurability as beam splitter or wavelength converter, it could pave the way for superconducting qubit processors with multiplexed on-chip signal processing and readout.Nonreciprocal optical elements often require magnetic materials in order to break time-reversal symmetry. Here, Barzanjeh et al. demonstrate a magnetic-free on-chip microwave circulator that utilizes the interference from six electro-mechanical signal paths.