The quantum bits (qubits) on which superconducting quantum computers are based have energy scales corresponding to photons with GHz frequencies. The energy of photons in the gigahertz domain is too low to allow transmission through the noisy room-temperature environment, where the signal would be lost in thermal noise. Optical photons, on the other hand, have much higher energies, and signals can be detected using highly efficient single-photon detectors. Transduction from microwave to optical frequencies is therefore a potential enabling technology for quantum devices. However, in such a device the optical pump can be a source of thermal noise and thus degrade the fidelity; the similarity of input microwave state to the output optical state. In order to investigate the magnitude of this effect we model the sub-Kelvin thermal behavior of an electro-optic transducer based on a lithium niobate whispering gallery mode resonator. We find that there is an optimum power level for a continuous pump, whilst pulsed operation of the pump increases the fidelity of the conversion.

超导量子计算机所基于的量子位（qubits）具有对应于具有 GHz 频率的光子的能量标度。千兆赫域中的光子能量太低，无法通过嘈杂的室温环境进行传输，在那里信号会在热噪声中丢失。另一方面，光子具有更高的能量，并且可以使用高效的单光子探测器来探测信号。因此，从微波到光学频率的转换是量子设备的潜在使能技术。然而，在这样的设备中，光泵可能是热噪声的来源，从而降低保真度；输入微波状态与输出光学状态的相似性。为了研究这种效应的大小，我们对基于铌酸锂回音壁模式谐振器的电光换能器的亚开尔文热行为进行建模。我们发现连续泵存在最佳功率水平，而泵的脉冲操作提高了转换的保真度。