Posterior laser-locking technique for MDI-QKD

Physical optics

We present a novel soft-ware based method to ensure independent lasers mutual coherence required for practical realization of advanced Measurement Device Independent Quantum Key Distribution (MDI-QKD) protocols. Proof of principle experiment has proved validity of the method, providing mutual coherence time while upper bound dictated by uncontrollable phase drift in optical fiber being ~ 100 µs.