We investigated local magnetic flux biasing (LFB) that induces a phase shift in superconductor circuits by locally applying a magnetic field through the superconductor loop with Josephson junctions. The arbitrary phase shift can be achieved using LFB without modifying the circuit fabrication process. To quantitatively evaluate the effects of introducing LFB for practical superconductor circuit applications, we designed a single flux quantum (SFQ) based non-destructive read-out flip-flop with complementary outputs (NDROC) and a delay flip-flop with complementary outputs (DFFC). The circuit area and static power consumption of the NDROC based on LFB architecture (LFB-NDROC) are approximately 67% and 36% of a conventional NDROC, respectively. The measured bias margin of the LFB-NDROC was in the range of 69%–129%. Using LFB, we were able to reduce the circuit area and power consumption for the DFFC by 67% and 83%, respectively. The measured bias margin of the DFFC with LFB was between 115% and 128%. LFB enabled us to implement a 5-to-32 SFQ decoder which comprises NDROC trees with a reduced circuit area of approximately 60% of a conventional decoder. The results obtained in this study can be applied to not just SFQ circuits but other superconductor circuits also, as they improve the area and power efficiency of such circuits.

我们研究了局部磁通偏置 (LFB)，该偏置通过通过具有约瑟夫森结的超导体回路局部施加磁场而在超导体电路中引起相移。使用 LFB 可以实现任意相移，而无需修改电路制造工艺。为了定量评估引入 LFB 对实际超导体电路应用的影响，我们设计了一种基于单通量量子 (SFQ) 的具有互补输出 (NDROC) 的非破坏性读出触发器和具有互补输出的延迟触发器 (DFFC) ）。基于LFB架构的NDROC（LFB-NDROC）的电路面积和静态功耗分别约为传统NDROC的67%和36%。LFB-NDROC 的测量偏差裕度在 69%–129% 的范围内。使用 LFB，我们能够将 DFFC 的电路面积和功耗分别减少 67% 和 83%。测得的带 LFB 的 DFFC 的偏置裕度在 115% 到 128% 之间。LFB 使我们能够实现 5 到 32 SFQ 解码器，该解码器包含 NDROC 树，电路面积约为传统解码器的 60%。本研究中获得的结果不仅可以应用于 SFQ 电路，还可以应用于其他超导体电路，因为它们可以改善此类电路的面积和功率效率。