Fig. 4: Quantum frequency converter.
From: Telecom quantum photonic interface for a 40Ca+ single-ion quantum memory
a Schematic quantum frequency conversion setup. Details are found in the main text. TDFL thulium-doped fiber laser, LPF low-pass filter, BPF band-pass filter, VBG volume-Bragg grating, DM dichroic mirror, HWP half-wave plate, SNSPD superconducting nanowire single-photon detector; b Device efficiency of the converter for different pump powers and input polarizations. The maximum efficiencies of the H- and V-polarizations are slightly different.
