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Annual Report

Demonstration of SQUID (Superconducting QUantum Interference Device) parametric amplifier

Arnold H. Silver, R. Sandell, Reggie Phillips, A. D. Smith

Published Nov 1, 1982• 0 citations
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Abstract

This is the first Annual Report of an effort to demonstrate a low noise superconducting microwave amplifier. The amplifier is a nearly degenerate, single idler parametric amplifier which uses the nonlinear inductance of a single junction SQUID (Superconducting Quantum Interference Device). The design frequency is 9 GHz, 10 dB gain, and 16% bandwidth. In order to maximize the saturation power, the device impedance was chosen near 1ohm and a matching network was designed to transform to 50ohm. In later designs, a coherent array of SQUIDs is expected to increase the power and impedance. This report includes the design and test of the 50ohm to 1ohm broadband transformer, design and fabrication of the SQUID amplifier, and both saturation and noise analyses of the single SQUID and SQUID array. The analytical results, reported to the 1982 Applied Superconductivity Conference are: the noise temperature of the single SQUID parametric amplifier is equal to the amplifier termination temperature T(o), the response is linear to several percent of the flux quantum energy in the SQUID: the amplifier will be saturated by broad band noise if the noise source temperature is much greater than 10 To; and the array parametric amplifier has the same noise temperature as the single device indicating an N-fold increase in dynamic range. (Author)

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The authors report a SQUID (superconducting quantum interference device) amplifier with a novel tuning circuit that can be easily coupled to a finite-impedance source. The SQUID amplifier is designed for a source impedance of 50 Omega and a signal frequency of nearly 150 MHz. The performance of the SQUID amplifier has been measured at 4.2 K. The measured gain and noise temperature of the SQUID amplifier are 20 dB and 0.7 K, respectively. A saturation temperature as high as 200 K at the input of the SQUID amplifier is achieved. It is concluded that this type of tuned SQUID amplifier is applicable to the IF (intermediate frequency) amplifier of the SIS (superconductor-insulator-semiconductor) receiver.>

IEEE Transactions on Magnetics•Mar 1, 1989•15 citations
This is the first Annual Report of an effort to demonstrate a low noise superconducting microwave amplifier. The amplifier is a nearly degenerate, single idler parametric amplifier which uses the nonlinear inductance of a single junction SQUID (Superconducting Quantum Interference Device). The design frequency is 9 GHz, 10 dB gain, and 16% bandwidth. In order to maximize the saturation power, the device impedance was chosen near 1ohm and a matching network was designed to transform to 50ohm. In later designs, a coherent array of SQUIDs is expected to increase the power and impedance. This report includes the design and test of the 50ohm to 1ohm broadband transformer, design and fabrication of the SQUID amplifier, and both saturation and noise analyses of the single SQUID and SQUID array. The analytical results, reported to the 1982 Applied Superconductivity Conference are: the noise temperature of the single SQUID parametric amplifier is equal to the amplifier termination temperature T(o), the response is linear to several percent of the flux quantum energy in the SQUID: the amplifier will be saturated by broad band noise if the noise source temperature is much greater than 10 To; and the array parametric amplifier has the same noise temperature as the single device indicating an N-fold increase in dynamic range. (Author)
TRW has been developing low noise microwave parametric amplifier with Josephson junction SQUIDs (Superconducting Quantum Interference Devices). This report summarizes the second phase of the program which includes measurement of the amplifier performance at X-band, and design and fabrication of a SQUID array amplifier. We have demonstrated gain in excess of 10 dB at 8.4 GHz and a measured noise temperature equal to 6K with an uncertainty of (+15/-7)K. Arrays with both 25 and 50 elements and 50 ohmi impedance have been designed and fabricated. These arrays should increase the dynamic range of the amplifier.
We report the lowest noise temperature of any microwave amplifier except the maser. This amplifier is a nearly degenerate superconducting parametric amplifier at X-band consisting of a low β, thin film, single junction SQUID, a monolithic 50 Ω to 1 Ω impedance matching network, and a cooled circulator. Nb/Nb2O5/Pb alloy junctions were incorporated into Nb and Pb-in circuitry on 1×2 cm silicon chips. The SQUID was phase-biased near 90° and driven by an external pump at approximately twice the operating frequency. The self-resonance frequency of the SQUID inductance and junction capacitance was set at the operating frequency of 8.2GHz. The operating charac teristics depended on the pump amplitude, the junction phase bias, and the SQUID parameters. For small values of\beta < 1, the maximum gain in both the signal and idler channels was ≈10dB, the bandwidth = 170MHz, and the single-sidehand noise temperature was 6K with an uncertainty of (+15 to -7)K. For higher β, the gain increased to nearly 30dB with increased noise and parametric oscillations occurring near the pump subharmonic frequency.
The single junction SQUID was previously shown by analysis and simulation to be an attractive candidate for a parametric amplifier. Further calculations of the noise and saturation behavior of the nearly degenerate parametric amplifier have now been performed by numerical simulation. These simulations clearly show that the amplifier noise temperature will be approximately the device temperature T0, and that the amplifier will be completely saturated in the presence of white noise characteristic of 30T0. Signal saturation of the amplifier also occurs for an output power10^{-2}F_{o}\phi_{o}^{2}/2L, strongly limiting the dynamic range, However, a coherent array of N single junction SQUIDs is shown to have a signal saturation level increased by N relative to a single SQUID, with no increase in noise temperature, resulting in an N-fold improvement in dynamic range.
We have developed and measured a high-gain quantum-limited microwave parametric amplifier based on a superconducting lumped LC resonator with the inductor L including an array of eight superconducting quantum interference devices (SQUIDs). This amplifier is parametrically pumped by modulating the flux threading the SQUIDs at twice the resonator frequency. Around 5 GHz, a maximum gain of 31 dB, a product amplitude gain $\ifmmode\times\else\texttimes\fi{}$ bandwidth above 60 MHz, and a 1 dB compression point of $\ensuremath{-}123$ dBm at 20 dB gain are obtained in the nondegenerate mode of operation. Phase-sensitive amplification-deamplification is also measured in the degenerate mode and yields a maximum gain of 37 dB. The compression point obtained is 18 dB above what would be obtained with a single SQUID of the same inductance, due to the smaller nonlinearity of the SQUID array.
Abstract High-performance cryogenic amplifiers are essential components for quantum information technology and astronomical observation. In this work, we report the design and characterization of a microwave amplifier based on a superconducting quantum interference device (SQUID). The design incorporates input and output impedance transformers to center the operating frequency at approximately 5.5 GHz for specific applications. Preliminary characterization at a bath temperature of 4.2 K demonstrates a peak gain of 10.79 dB at 5.39 GHz and a saturation power of approximately −115 dBm.
The authors report a SQUID (superconducting quantum interference device) amplifier with a novel tuning circuit that can be easily coupled to a finite-impedance source. The SQUID amplifier is designed for a source impedance of 50 Omega and a signal frequency of nearly 150 MHz. The performance of the SQUID amplifier has been measured at 4.2 K. The measured gain and noise temperature of the SQUID amplifier are 20 dB and 0.7 K, respectively. A saturation temperature as high as 200 K at the input of the SQUID amplifier is achieved. It is concluded that this type of tuned SQUID amplifier is applicable to the IF (intermediate frequency) amplifier of the SIS (superconductor-insulator-semiconductor) receiver.>