Abstract
A Josephson parametric amplifier (JPA) can create squeezed states of microwave light, lowering the noise associated with certain quantum measurements. We experimentally study how the JPA’s pump influences the phase-sensitive amplification and deamplification of a coherent tone’s amplitude when that amplitude is commensurate with vacuum fluctuations. We predict and demonstrate that, by operating the JPA with a single current pump whose power is greater than the value that maximizes gain, the amplifier distortion is reduced and, consequently, squeezing is improved. Optimizing the singly pumped JPA’s operation in this fashion, we directly observe of vacuum squeezing over a bandwidth of 30 MHz.
2 More- Received 7 November 2017
- Revised 10 January 2018
DOI:https://doi.org/10.1103/PhysRevApplied.9.044023
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