1 GHz Waveform Synthesis With Josephson Junction Arrays

Area of Science:

• Quantum electronics
• High-frequency signal generation

Background:

• Josephson junctions offer a quantum-based method for precise signal synthesis.
• Existing methods for gigahertz waveform generation face limitations in spectral purity and power control.

Purpose of the Study:

• To synthesize single- and multiple-tone gigahertz waveforms using Josephson junction arrays.
• To demonstrate quantum-locked operation and spectrally selective programmability.
• To advance the development of a Josephson Arbitrary Waveform Synthesizer (JAWS)-based primary RF reference source.

Main Methods:

• Utilized lumped-element circuits for initial waveform synthesis (1-2 GHz).
• Introduced a narrow-band diplexer circuit for enhanced power and spectral purity.
• Synthesized single-tone and multisine waveforms with controlled power and phase.

Main Results:

• Achieved -71 dBm output power and -66 dBc spurious-free dynamic range (SFDR) for single-tone waveforms.
• With a diplexer, synthesized a 1 GHz sinusoid at -49 dBm with -79 dBc in-band SFDR.
• Demonstrated spectrally selective power and phase programmability using multisine waveforms.

Conclusions:

• The quantized pulse-based synthesis technique is not the limiting factor for spectral purity.
• Room-temperature electronics currently limit spectral purity, indicating areas for future circuit design improvements.
• Significant progress has been made towards a JAWS-based primary RF reference source for programmable, quantum-referenced, low-distortion gigahertz signals.