Lu Xiyuan, Moille Gregory, Rao Ashutosh, Srinivasan Kartik
Opt Lett. 2021 Jan 15;46(2):222-225. doi: 10.1364/OL.412602.
Quantum frequency conversion (QFC) between the visible and telecom is a key to connect quantum memories in fiber-based quantum networks. Current methods for linking such widely separated frequencies, such as sum/difference frequency generation and four-wave mixing Bragg scattering, are prone to broadband noise generated by the pump laser(s). To address this issue, we propose to use third-order sum/difference frequency generation (TSFG/TDFG) for an upconversion/downconversion QFC interface. In this process, two long wavelength pump photons combine their energy and momentum to mediate frequency conversion across the large spectral gap between the visible and telecom bands, which is particularly beneficial from the noise perspective. We show that waveguide-coupled silicon nitride microring resonators can be designed for efficient QFC between 606 and 1550 nm via a 1990 nm pump through TSFG/TDFG. We simulate the device dispersion and coupling, and from the simulated parameters, estimate that the frequency conversion can be efficient (${\gt}80 %$) at 50 mW pump power. Our results suggest that microresonator TSFG/TDFG is promising for compact, scalable, and low-power QFC across large spectral gaps.
可见光与电信波段之间的量子频率转换（QFC）是连接基于光纤的量子网络中量子存储器的关键。目前用于连接如此广泛分离频率的方法，如和频/差频产生以及四波混频布拉格散射，容易受到泵浦激光器产生的宽带噪声影响。为了解决这个问题，我们提议使用三阶和频/差频产生（TSFG/TDFG）来实现上转换/下转换QFC接口。在这个过程中，两个长波长泵浦光子结合它们的能量和动量，以介导跨越可见光和电信波段之间大光谱间隙的频率转换，从噪声角度来看这特别有益。我们表明，通过TSFG/TDFG，波导耦合的氮化硅微环谐振器可以设计用于在606和1550纳米之间通过1990纳米泵浦实现高效的QFC。我们模拟了器件的色散和耦合，并根据模拟参数估计，在50毫瓦泵浦功率下频率转换可以是高效的（大于80%）。我们的结果表明，微谐振器TSFG/TDFG对于跨越大型光谱间隙的紧凑、可扩展和低功耗QFC具有前景。
