Non-degenerate-pump four-wave mixing kinetic inductance travelling-wave parametric amplifiers

Abstract

Kinetic inductance travelling-wave parametric amplifiers (KITWPAs) have been demonstrated to achieve high gain over broad bandwidths whilst achieving near quantum-limited noise performance, properties which are extremely important for many ultra-sensitive experiments. In early KITWPA designs, the requirement for phase-matching lead to the creation of a large zero-gain gap in the centre of the gain profile where the peak gain is, which also slightly narrows down the operational bandwidth of the device. This has been mitigated in more recent designs by introducing a DC bias to the KITWPA device, which allows the gap to be tuned away from the amplification band. However, the added DC biasing requires a more complicated experimental setup and potentially leads to unwanted heat leak in the cryogenic environment. Additionally, operation with a DC bias also become challenging at higher frequencies beyond the microwave regime. In this paper, we present the concept of a KITWPA operating in a non-degenerate-pump four-wave mixing (NP-4WM) regime, whereby the injection of two pump tones along with a weak signal results in a broad, flat gain profile that removes the zero-gain gap as well as eliminates the need for a DC bias and the complexities associated with it. We demonstrate how a NP-4WM KITWPA is feasible to achieve broadband amplification at a range of frequencies, first in the microwave range where most KITWPAs reported to-date have been successfully experimentally characterised. We then extend the designs to several millimetre (mm) bands to illustrate how we can use this technique to design a broadband front-end pre-amplifier that covers several Atacama Large Millimetre/sub-millimetre Array (ALMA) Bands.

Balanced travelling-wave parametric amplifiers for practical applications

“…Another significant challenge in the practical operation of a TWPA is the complexity of the required experimental setup. As illustrated in figure 2, a typical experimental arrangement for operating a NP-4WM TWPA [24] involves a multitude of additional components such as directional couplers, power dividers, variable attenuators, and phase shifters, which are essential for combining the pump and signal tones before injecting them into the TWPA and subsequently cancelling the pump tones post-amplification. These added components are often physically larger than the TWPA itself and must be mounted at various cryogenic stages, consuming valuable space within the cryostat.…”

“…The physical configuration is identical to that shown in figure 9, except the second pump tone is now injected at the same input port as the signal, which results in the signal and one of the pump tones being present at one of the output ports, and the idler and other pump tone being present at the other. As with figure 8, this configuration solves the signal-idler contamination with the added advantage of operating a balanced-TWPA in the NP-4WM regime, where the zero-gain gap in the centre of the gain profile is eliminated [24], resulting in an extremely wide and uniform gain profile. Given that the pumps are located at the edges of the gain profile means that they can be easily filtered out using a band-pass filter, hence enabling the full bandwidth of the TWPA to be utilised.…”

“…The first generation of TWPAs operating in the degenerate-pump four-wave mixing (DP-4WM) mode [1,22] exhibited undesirable characteristics, such as a large zero-gain gap at the centre of the gain profile and gain roll-off. These issues have been addressed in second-generation devices, which operate the TWPA in either the dual-pump non-degenerate-pump four-wave mixing (NP-4WM) mode [23,24] or the DCinduced three-wave mixing (DC-3WM) regime [2,11]. Despite these improvements, however, TWPAs still face challenges that hinder their widespread use beyond superconducting quantum computing fields e.g.…”

Microwave assisted efficient non-degenerate four-wave mixing in pulsed regime

“…Four wave mixing is a well-known nonlinear phenomena which has been studied in diverse systems such as photonic crystals [1,2], optical fiber [3][4][5], atomic medium [6][7][8][9], quantum dot [10,11], superconducting material [12], opto-magnomechanical system [13], bulk media [14] etc. FWM in atomic medium attracts particular interest due to its numerous advantages over other systems.…”