Optical quantum memory based on electro-optically silenced photon echo

Integrated quantum memories are a scalable solution to synchronize a large number of quantum computers, which are essential to build a quantum network to boost their capabilities on information processing. Rather than expecting to find a specific kind of atoms to meet all the requirements of a good quantum memory, as other protocols usually do, we propose that assigning the memory requirements on coherence property and control property to rare earth ions and lithium niobate crystal, respectively. In particular, optical quantum states are stored into erbium doped lithium niobate (Er$^{3+}$:LiNbO$_3$) micro-cavity by utilizing the electro-optic effect of LiNbO$_3$. The Er$^{3+}$:LiNbO$_3$ cavity frequency can be shifted by an external electric field, which is used to control the photon-echo emission by changing the resonance condition between micro-cavity and collective atomic excitation. According to calculations, high efficiency and low noise storage can be achieved. Benefiting from the host lithium-niobate thin film, such a device can be controlled by on-chip electrodes and is easy to be integrated with modern photonic devices, paving way of integrated quantum chips