QCI - Amplifier


QCI - Performance


  • Gain: 20 dB
  • Bandwidth: ~ 10 MHz
  • Saturation P-1dB : ~ -125 dBm
  • Noise temperature: ~ 0.5 K*
  • Mode tunability: ~ 400 MHz from listed frequency.

* System noise temperature < 1 K requires cryo-HEMT following amplifier.

Mode tunability

  • Small (~ 50 MHz) shifts in center frequency accomplished by varying pump frequency.
  • Larger shifts (up to 400 MHz) via magnetic bias.
  • Each amplifier has two modes which can be used interchangeably for enhanced flexibility.
  • Standard mode frequencies are 9 GHz and 5 GHz, or 7.5 GHz and 5 GHz.

Gain control

  • Amplifier gain is controlled by amplitude of microwave pump.
  • Increase gain for weaker signals or to compensate for noise of following amplifier.
  • Decrease gain to maximize dynamic range and bandwidth.
  • Stable rf bias is crucial, see application notes for acceptable generators.

Multi-layer shield

QCI - Multi-layer shield

Cryoperm and aluminum magnetic shields.
Copper backbone holds amplifier inside shield together with hybrid couplers.
Total size 8.9” H x 2.6” Ø

Alternate applications

  • Two port amplification with frequency conversion.
  • Noiseless frequency conversion.
  • Dynamically controllable beam splitter (with frequency conversion).
  • Directional amplification.

Operation principle

QCI - Operation principle
  • Two modes (A and B, at two different frequencies) are available for amplification.
  • Connect signal to be amplified to appropriate frequency port (A or B) via microwave circulator (not provided). Terminate other port with cold matched load.
  • Bias flux coil with dc current; apply microwave drive tone to pump port.

Purchase options

  • Option 1 : Bare amplifier (golden case, bias coil, hybrids, and matched rf cables).
  • Option 2 : Bare amplifier + mount + multi-layer magnetic shielding.

All amplifiers are provided fully tested with data sheet and one year off-site warranty.
Phone and email support are available free of charge. On-site training can be purchased.

Experiments Enabled

QCI - Experiments Enabled

Quantum jumps of a transmon artificial atom.
Horizontal tick marks every 50 microseconds.

  • Realtime qubit and cavity monitoring/feedback :
    Ofek et al., Nature 536, 441 (2016).
    Leghtas et al., Science 347, 853 (2015).
    Sun et al., Nature 511, 444 (2014).
    Shankar et al., Nature 504, 419 (2013).
  • Quantum measurement :
    Hatridge et al.,
    Science 339, 178 (2013).

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