Frequency-Multiplexed Storage and Distribution of Narrowband Telecom Photon Pairs over a 10-km Fiber Link with Long-Term System Stability

Characterisation of storage efficiency in magnetic field for extending coherence time of Pr:YSO quantum memory

“…Moreover, the number of spectral modes is determined by dividing the inhomogeneous broadening by the range occupied by an AFC. 9,10) A Eu-based AFC with a dopant concentration of 0.1% has an inhomogeneous broadening of 1.6 GHz, and the AFC occupies a range of 516 MHz; hence, it is calculated as three modes. 7) A Pr-based AFC has an inhomogeneous broadening higher than 10 GHz and a range of 78.3 MHz occupied by one AFC; hence, more than 100 modes are available.…”

Phase locking and absolute frequency stabilization of laser sources for a Pr:YSO quantum memory

“…), is called 'quantum frequency conversion' 15,24) because it involves the frequency conversion of photons. A quantum-memory control laser is used to generate AFCs in the quantum memories.…”

“…21) Therefore, the quantummemory control laser, TPS, and frequency-conversion pump laser must be frequency-stabilized within this frequency range. In frequency-multiplexed Pr:YSO memory, multiple AFCs with comb spacings close to 500 kHz were generated, 24,25) and precise laser frequency control was required. Therefore, we set the laser frequency requirement for the operation of a Pr:YSO quantum memory to 50 kHz (1/ 10 of 500 kHz).…”