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

Abstract

We propose a scheme to phase lock a quantum-memory control laser, frequency-conversion pump laser, and two-photon source over three octaves in frequency to operate a quantum memory. The absolute frequencies of the laser sources are determined based on a Doppler-free iodine hyperfine transition. The achieved relative frequency instability and uncertainty were ≤1 × 10–12 and 3 × 10–11, respectively, which are below the requirement for operating a Pr:YSO quantum memory. This scheme simplifies the instrumentation of laser sources in a quantum repeater, and increases the reliability of quantum communication systems.