Parametric oscillator

About: Parametric oscillator is a research topic. Over the lifetime, 5836 publications have been published within this topic receiving 95631 citations. The topic is also known as: Parametric excitation.

Strongly quadrature-dependent noise in superconducting micro-resonators measured at the vacuum-noise limit

Abstract: We measure frequency- and dissipation-quadrature noise in superconducting lithographed microwave resonators with sensitivity near the vacuum noise level using a Josephson parametric amplifier. At an excitation power of 100~nW, these resonators show significant frequency noise caused by two-level systems. No excess dissipation-quadrature noise (above the vacuum noise) is observed to our measurement sensitivity. These measurements demonstrate that the excess dissipation-quadrature noise is negligible compared to vacuum fluctuations, at typical readout powers used in micro-resonator applications. Our results have important implications for resonant readout of various devices such as detectors, qubits and nano-mechanical oscillators.

Multi-Watt femtosecond optical parametric master oscillator power amplifier at 43 MHz.

Abstract: We present a high repetition rate mid-infrared optical parametric master oscillator power amplifier (MOPA) scheme, which is tunable from 1370 to 4120nm. Up to 4.3W average output power are generated at 1370nm, corresponding to a photon conversion efficiency of 78%. Bandwidths of 6 to 12nm with pulse durations between 250 and 400fs have been measured. Strong conversion saturation over the whole signal range is observed, resulting in excellent power stability. The system consists of a fiber-feedback optical parametric oscillator that seeds an optical parametric power amplifier. Both systems are pumped by the same Yb:KGW femtosecond oscillator.

Oscillator having a transistor formed of a wide bandgap semiconductor material

Abstract: An oscillator and upconverters and downconverters including the oscillator are provided, wherein the oscillator includes a transistor comprised of a semiconductor material having a wide bandgap for producing RF output signals For example, the transistor can be formed of a semiconductor material, such as GaN, AlGaN, SiC or BN, that has a bandgap of at least 20 eV The oscillator also includes a bias supply for providing a supply voltage and a supply current Additionally, the oscillator has a tank circuit that includes first and second reactances connected to respective terminals of the transistor such that the transistor is unstable and an oscillating RF output signal is produced The tank circuit can also include a varactor connected to a respective reactance and a control input is provided to tune the oscillating RF output signal Upconverters, both saturated and linear, and downconverters are also provided that include the oscillator

Stabilization of the Parametric Resonance of a Cantilever Beam by Bifurcation Control with a Piezoelectric Actuator

Abstract: In this work, bifurcation control using a piezoelectric actuator isimplemented to stabilize the parametric resonance induced in acantilever beam. The piezoelectric actuator is attached to the surfaceof the beam to produce a bending moment in the beam. The dimensionlessequation of motion for the beam with the piezoelectric actuator on itssurface is derived and the modulation equations for the complexamplitude of an approximate solution are obtained using the method ofmultiple scales. We then acquire the bifurcation set that expresses theboundary of the stable and unstable regions. The bifurcation set ischaracterized by the modulation equations. Next, we determine the orderof feedback gains to modify these modulation equations. By actuating thepiezoelectric actuator under the appropriate feedback, bifurcationcontrol is carried out resulting in the shift of the bifurcation set andthe expansion of the stable region. The main characteristic of thestabilization method introduced above is that the work done by thepiezoelectric actuator is zero in the state where the parametricresonance is stabilized. Thus zero power control is realized in such astate. Experimental results show the validity of the proposedstabilization method for the parametric resonance induced in thecantilever beam.