This paper is available on arxiv under CC 4.0 license.
Authors:
(1) Terence Blésin, Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL) & Center of Quantum Science and Engineering (EPFL);
(2) Wil Kao, Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL) & Center of Quantum Science and Engineering (EPFL);
(3) Anat Siddharth, Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL) & Center of Quantum Science and Engineering (EPFL);
(4) Alaina Attanasio, OxideMEMS lab, Purdue University;
(5) Hao Tian, OxideMEMS lab, Purdue University;
(6) Sunil A. Bhave, OxideMEMS lab, Purdue University;
(7) Tobias J. Kippenberg, Institute of Physics, Swiss Federal Institute of Technology Lausanne (EPFL) & Center of Quantum Science and Engineering (EPFL).
Results
Given the measured off-chip efficiency, the single-photon coupling rate can be estimated. The off-chip efficiency is given by
where ηprobes and ηfiber-chip denote the microwave and optical insertion losses, respectively. The on-chip efficiency can be written as
The internal efficiency
in the low-cooperativity regime, where the plus and minus signs correspond to the anti-Stokes and Stokes configurations, respectively. The optical and microwave extraction efficiencies
The single-photon cooperativity C0 is enhanced by the intracavity photons
where the pump detuning is assumed to be small. The input power in the bus waveguide Pwg is related to the power in the input fiber Pin by the fiber-chip coupling efficiency
The off-chip efficiency with respect to the microwave probe and optical fiber is thus
We have achieved η tot = −48 dB at an input pump power of 21 dBm. With the losses quoted in Appendix E 1, the on-chip and internal efficiencies can be estimated. For conversion in either directions, the signal goes through the respective input and output ports exactly once, acquiring an attenuation of η probesη fiber−chip = −7 dB. We therefore have η oc = 7.9×10−5 . Knowing the extraction efficiencies ηo = 35% and ηm = 11%, we further obtain η int = 2×10−3 .