For applications where extremely low-noise amplifiers are demanded, RF SQUID parametric amplifiers offer significant capabilities. We present results on the first RF SQUID parametric amplifiers (paramp) fabricated using TRW's YBCO integrated circuit process technology. TRW's paramps consist of thousands of RF SQUIDs distributed along and coupled to /spl sim/7 cm coplanar transmission lines. We demonstrate two important paramp functions: adjustable true time delay of RF signals and frequency upconversion of 0 to 1 GHz base band signals to side bands of the /spl sim/10 GHz pump. When the input and output impedances are different the correct figure of merit is upconversion transimpedance gain, shown to be proportional to pump frequency and independent of base band frequency, thereby providing wide band signal amplification. Finally, the spur-free dynamic range for these first paramps is inferred from measurement and modeling to be /spl sim/82 dB-/spl radic/Hz.
For applications where extremely low-noise amplifiers are demanded, RF SQUID parametric amplifiers offer significant capabilities. We present results on the first RF SQUID parametric amplifiers (paramp) fabricated using TRW's YBCO integrated circuit process technology. TRW's paramps consist of thousands of RF SQUIDs distributed along and coupled to /spl sim/7 cm coplanar transmission lines. We demonstrate two important paramp functions: adjustable true time delay of RF signals and frequency upconversion of 0 to 1 GHz base band signals to side bands of the /spl sim/10 GHz pump. When the input and output impedances are different the correct figure of merit is upconversion transimpedance gain, shown to be proportional to pump frequency and independent of base band frequency, thereby providing wide band signal amplification. Finally, the spur-free dynamic range for these first paramps is inferred from measurement and modeling to be /spl sim/82 dB-/spl radic/Hz.
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.
A 6 mm/spl times/6 mm chip comprising two identical DC SQUID based amplifiers (SQAs) has been designed, fabricated and tested as a two-stage RF amplifier in a frequency range 3.5-4.0 GHz. Each SQA consists of a double washer type DC SQUID with novel integrated input resonant circuit. The reflection coefficient of both input and output of the SQA has been measured in the two stage configuration. To avoid SQA saturation at the wide band noise tests a tunable 40 MHz bandpass YIG-filter has been used. The following parameters of the two-stage SQA have been measured at the 3.65 GHz: gain of (17.5/spl plusmn/1) dB, 3 dB bandwidth of about 250 MHz, and noise temperature (4.0/spl plusmn/0.5)K what corresponds to intrinsic flux noise S/spl phi//sup 1/2//spl ap/0.6 /spl mu//spl Phi//sub 0/Hz/sup -1/2/ and energy sensitivity /spl epsiv//sub i//spl ap/75 /spl planck/ (7.8/spl middot/10/sup -33/ J/Hz). If the measured RF mismatch between the input/output of SQA and source signal/post-amplifier is taken into account a gain of (20.5/spl plusmn/1.5) dB and noise temperature as low as (2.5/spl plusmn/1.0) K (intrinsic flux noise S/spl phi//sup 1/2//spl ap/0.4 /spl mu//spl Phi//sub 0/Hz/sup -1/2/, energy sensitivity /spl epsiv//sub i//spl ap/47 /spl planck/) can be estimated.
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)
Experimental results are reported on a Josephson parametric upconverting amplifier which is self-pumped via the internal Josephson oscillations derived from a dc bias voltage. A niobium point-contact SQUID is simultaneously coupled to a 115-MHz tank circuit and a 9-GHz cavity. Josephson oscillations at 9 GHz produce parametric upconversion of power in the 115-MHz circuit to sidebands at 9±0.115 GHz with measured power gain of 25. The amplifier noise temperature, referred to the input at 115 MHz, was established to be <15 K by varying the temperature of an input termination from 4.2 to 300 K. This result establishes the behavior of self-pumped SQUID upconverters at microwave frequencies and demonstrates that the achievable noise performance is not greatly in excess of the thermal limit.
Superconducting travelling-wave parametric amplifiers (TWPAs) provide broadband gain, low added noise, and high dynamic range, making them attractive for applications requiring wide instantaneous bandwidth. This is crucial for amplifying multiplexed narrow band signals spread over a wide frequency range, such as qubit resonator arrays, or amplifying inherently wide band signals, such as in spectrometers or radiometers. In many cases, however, the useful bandwidth of a TWPA is limited by the production of the idler tone at an image frequency. For three-wave-mixing (3WM) TWPAs, for example, an input signal at fs is indistinguishable from one at fp−fs, which can produce spectral ambiguity when the input spectrum is broadband or not known in advance. We experimentally demonstrate a balanced architecture that doubles the instantaneous image-rejected bandwidth available to a 3WM TWPA by spatially separating the amplified signal from the output pump and generated idler, which resolves the sideband degeneracy. The architecture consists of two amplifiers connected between a pair of 180∘ hybrid couplers, with the signal and pump injected and output through the sum and difference ports, respectively. Using two kinetic-inductance TWPAs, we demonstrate approximately 20 dB of signal gain across nearly an octave of bandwidth, together with pump rejection below --20 dB and an average image rejection of approximately --15 dB over the operating band. These results establish balanced TWPAs as a practical approach to broadband parametric amplification, enabling improved contamination free bandwidth and eliminating the need for complex filtering.
Amplifiers are ubiquitous in electronics and play a fundamental role in a wide range of scientific measurements. From a user's perspective, an ideal amplifier has very low noise, operates over a broad frequency range, and has a high dynamic range - it is capable of handling strong signals with little distortion. Unfortunately, it is difficult to obtain all of these characteristics simultaneously. For example, modern transistor amplifiers offer multi-octave bandwidths and excellent dynamic range. However, their noise remains far above the fundamental limit set by the uncertainty principle of quantum mechanics. Parametric amplifiers, which predate transistor amplifiers and are widely used in optics, exploit a nonlinear response to transfer power from a strong pump tone to a weak signal. If the nonlinearity is purely reactive, ie. nondissipative, in theory the amplifier noise can reach the quantum-mechanical limit. Indeed, microwave frequency superconducting Josephson parametric amplifiers do approach the quantum limit, but generally are narrow band and have very limited dynamic range. In this paper, we describe a superconducting parametric amplifier that overcomes these limitations. The amplifier is very simple, consisting only of a patterned metal film on a dielectric substrate, and relies on the nonlinear kinetic inductance of a superconducting transmission line. We measure gain extending over 2 GHz on either side of an 11.56 GHz pump tone, and we place an upper limit on the added noise of the amplifier of 3.4 photons at 9.4 GHz. Furthermore, the dynamic range is very large, comparable to microwave transistor amplifiers, and the concept can be applied throughout the microwave, millimeter-wave and submillimeter-wave bands.