Multifunctional on-chip storage at telecommunication wavelength for quantum networks

Implementing optical quantum memories with frequency and bandwidth control are important for quantum information processing and communication. Rare earth ions in solids are one of the most promising platforms due to their long optical and spin coherence times. Erbium is of particular interest because it has an optical transition in the telecom band, which allows interfacing devices with silicon photonics and fiber communication networks.

We demonstrated optical storage using a hybrid amorphous silicon-Er:YSO photonic crystal resonator evanescently coupled to an ensemble of ions with gold electrodes adjacent to the resonator. Using on-chip electrodes, we created electric fields as high as 3 kV/cm with CMOS compatible applied voltages (5 V). We stored light using the atomic frequency comb protocol, and further manipulated the recalled output frequency and bandwidth through the DC stark shift achieved by applying an electric field. In this device, we demonstrated a memory time control in a digital fashion with an increment of 50 ns, frequency shifting of output photons by ±39 MHz, and a bandwidth increase of output photons from 6 MHz to 18 MHz.