论文标题
基于三波混合的高增益游览波参数放大器
A high gain travelling-wave parametric amplifier based on three-wave mixing
论文作者
论文摘要
我们扩展了在三波混合方案中运行的约瑟夫森连接波动波参数放大器（TWPA）的理论，我们提出了一种实现高增益的方案。连续的三模型[P. K. Tien，J。Appl。物理。 29，1347（1958）]一方面伸出来描述在没有上流转换的频谱截止的高频上的约瑟夫森连接链。另一方面，我们还为低频分散率接近线性的低频区域开发了连续的多模理论。我们发现，在这两种情况下，与连续三模型模型的预测相比，增益均显着降低，这是由于在高频下越来越强，并且在低频率下的上转换模式的产生。开发的理论与实验观察符合定量一致。为了恢复高增益，我们建议设计具有分散特征的链条，以形成两带频谱，并将泵频率放置在靠近光谱截止的上部带中。我们证明存在一个最佳位置，信号和泵相匹配，而上转换则被抑制。这会导致高增益，随着TWPA的长度呈指数增长。
We extend the theory for a Josephson junction travelling wave parametric amplifier (TWPA) operating in the three-wave mixing regime and we propose a scheme for achieving high gain. The continuous three-mode model [P. K. Tien, J. Appl. Phys. 29, 1347 (1958)] is on one hand extended to describe a discrete chain of Josephson junctions at high frequencies close to the spectral cutoff where there is no up-conversion. On the other hand, we also develop a continuous multimode theory for the low-frequency region where the frequency dispersion is close to linear. We find that in both cases the gain is significantly reduced compared to the prediction by the continuous three-mode model as the result of increasingly strong dispersion at the high frequencies and generation of up-converted modes at the low frequencies. The developed theory is in quantitative agreement with experimental observations. To recover the high gain, we propose to engineer a chain with dispersive features to form a two-band frequency spectrum and to place the pump frequency within the upper band close to the spectral cutoff. We prove that there exists a sweet spot, where the signal and the pump are phase matched, while the up-conversion is inhibited. This results in a high gain which grows exponentially with the length of the TWPA.
