Spectrally improved controllable frequency comb quantum memory

We propose a scheme of a universal block of broadband quantum memory consisting of three ring microresonators forming a controllable frequency comb and interacting with each other and with a common waveguide. We find the optimal parameters of the microresonators showing the possibility of highly efficient storage of light fields on this memory block and we demonstrate the procedure for gluing several memory blocks for increasing spectral range of the composite quantum memory while maintaining high efficiency.