Low-noise josephson junction-based directional amplifier
AssigneeYale University
InventorsBaleegh Abdo, Katrina Sliwa, Luigi Frunzio, Robert J. Schoelkopf, III, Michel Devoret
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Abstract
A low-noise directional amplifier includes a first port, a second port, a first coupler and a second coupler. The first port is coupled to a first coupler. The low-noise directional amplifier also includes at least two phase preserving amplifiers, a first phase preserving amplifier connected to the first coupler and a second coupler, and the second phase preserving amplifier connected to the first coupler and the second coupler.
Claims20
A low-noise directional amplifier comprising:
- a first port and a second port;
- a first coupler and a second coupler, wherein the first port and the second port are coupled to the first coupler;
- a first phase preserving amplifier connected to the first coupler and the second coupler;
- and
- a second phase preserving amplifier connected to the first coupler and the second coupler, wherein a phase of a pump signal of the first phase preserving amplifier is different from a phase of a pump signal of the second phase preserving amplifier, and the difference between the phase of the pump signal of the first phase preserving amplifier and the phase of the pump signal of the second phase preserving amplifier determines a non-reciprocity of the low-noise directional amplifier,
- wherein the first port is an input port configured to receive at least one input signal and the second port is an output port configured to output at least one output signal.
A method of amplifying a microwave signal, the method comprising acts of:
- receiving the signal at an input port of a directional amplifier;
- amplifying at least a portion of the signal using both a first parametric amplifier and a second parametric amplifier to create an amplified signal;
- and
- transmitting the amplified signal out an output port of the directional amplifier, wherein:
- the first parametric amplifier is pumped using a first microwave pump with a first phase;
- the second parametric amplifier is pumped using a second microwave pump with a second phase, wherein the difference between the first phase and the second phase is pi/2 radians;
- and
- a transmission of a signal from the input port to the output port is substantially 100% when no pump signals are applied to the first phase preserving amplifier and the second phase preserving amplifier.
An integrated circuit comprising:
- a low-noise directional amplifier comprising:
- a first port and a second port;
- a first coupler and a second coupler, wherein the first port and the second port are coupled to the first coupler;
- a first phase preserving amplifier connected to the first coupler and the second coupler;
- and
- a second phase preserving amplifier connected to the first coupler and the second coupler;
- and
- a qubit coupled to the low-noise directional amplifier such that the low-noise directional amplifier is configured to measure a state of the qubit,
- wherein:
- the first port is an input port configured to receive at least one input signal and the second port is an output port configured to output at least one output signal;
- a reflection gain amplitude of the first phase preserving amplifier is the same as a reflection gain amplitude of the second phase preserving amplifier and a transmission gain amplitude of the first phase preserving amplifier is the same as a transmission gain amplitude of the second phase preserving amplifier;
- and
- the reflection gain amplitude of the first phase preserving amplifier is greater than or equal to unity and less than a reciprocal of a transmission amplitude of the second coupler.
Dependencies are inferred from the claim text.