12,245 research outputs found
Advanced Concepts in Josephson Junction Reflection Amplifiers
Low-noise amplification atmicrowave frequencies has become increasingly
important for the research related to superconducting qubits and
nanoelectromechanical systems. The fundamental limit of added noise by a
phase-preserving amplifier is the standard quantum limit, often expressed as
noise temperature . Towards the goal of the
quantum limit, we have developed an amplifier based on intrinsic negative
resistance of a selectively damped Josephson junction. Here we present
measurement results on previously proposed wide-band microwave amplification
and discuss the challenges for improvements on the existing designs. We have
also studied flux-pumped metamaterial-based parametric amplifiers, whose
operating frequency can be widely tuned by external DC-flux, and demonstrate
operation at pumping, in contrast to the typical metamaterial
amplifiers pumped via signal lines at .Comment: 9 pages, 6 figure
Application of pressurized liquid nitrogen inside parametric-amplifier structures for input-noise-temperature improvement
Pressurized liquid nitrogen inside parametric amplifier structures for input, noise, and temperature improvement
Phase preserving amplification near the quantum limit with a Josephson Ring Modulator
Recent progress in solid state quantum information processing has stimulated
the search for ultra-low-noise amplifiers and frequency converters in the
microwave frequency range, which could attain the ultimate limit imposed by
quantum mechanics. In this article, we report the first realization of an
intrinsically phase-preserving, non-degenerate superconducting parametric
amplifier, a so far missing component. It is based on the Josephson ring
modulator, which consists of four junctions in a Wheatstone bridge
configuration. The device symmetry greatly enhances the purity of the
amplification process and simplifies both its operation and analysis. The
measured characteristics of the amplifier in terms of gain and bandwidth are in
good agreement with analytical predictions. Using a newly developed noise
source, we also show that our device operates within a factor of three of the
quantum limit. This development opens new applications in the area of quantum
analog signal processing
Understanding the saturation power of Josephson Parametric Amplifiers made from SQUIDs arrays
We report on the implementation and detailed modelling of a Josephson
Parametric Amplifier (JPA) made from an array of eighty Superconducting QUantum
Interference Devices (SQUIDs), forming a non-linear quarter-wave resonator.
This device was fabricated using a very simple single step fabrication process.
It shows a large bandwidth (45 MHz), an operating frequency tunable between 5.9
GHz and 6.8 GHz and a large input saturation power (-117 dBm) when biased to
obtain 20 dB of gain. Despite the length of the SQUID array being comparable to
the wavelength, we present a model based on an effective non-linear LC series
resonator that quantitatively describes these figures of merit without fitting
parameters. Our work illustrates the advantage of using array-based JPA since a
single-SQUID device showing the same bandwidth and resonant frequency would
display a saturation power 15 dB lower.Comment: 12 pages, 9 figures, Appendices include
Sub-kHz-level relative stabilization of an intracavity doubled continuous wave optical parametric oscillator using Pound-Drever-Hall scheme
We report the relative frequency stabilization of an intracavity frequency
doubled singly resonant optical parametric oscillator on a Fabry-Perot\'etalon.
The red/orange radiation produced by the frequency doubling of the intracavity
resonant idler is stabilized using the Pound-Drever-Hall locking technique. The
relative frequency noise of this orange light, when integrated from 1 Hz to 50
kHz, corresponds to a standard deviation of 700 Hz. The frequency noise of the
pump laser is shown experimentally to be transferred to the non resonant signal
beam
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