A friendly visit to Kaiserslautern

From 11th to 15th of November 2019 Prof. Dr. Sergey Moiseev, director of KQC was in Technical University of Kaiserslautern with a friendly visit.

He gave a talk on the scientific research of the center, putting the main focus on Quantum memory development. He later had discussions with the dean of the Physical department of TU Kaiserslautern and our good friends Prof. Dr. Artur Widera and Dr. Thomas Niederprüm. The topic was the joint Master degree program between TUKl and KAI representer by KQC under the GRIAT initiative.

Another highlight of the visit was a 4.5 hour tour around the laboratories of the Physics department of TUKl with Dr. Christian Hartmann lead by Dr. Thomas Niederprüm.

The main result of the visit was a strong confidence from both sides that KQC and TUKl must have a strong scientific collaboration which would benefit both research and joint master program of Advanced Quantum Technologies.

From left to right: Dr. Thomas Niederprüm, Dr. Christian Hartmann, Prof. Dr. Sergey Moiseev and master student Alexander Pavlov

A new research paper by A. Gleym

Secure polarization-independent subcarrier quantum key distribution in optical fiber channel using BB84 protocol with a strong reference

Abstract: A quantum key distribution system based on the subcarrier wave modulation method has been demonstrated which employs the BB84 protocol with a strong reference to generate secure bits at a rate of 16.5 kbit/s with an error of 0.5% over an optical channel of 10 dB loss, and 18 bits/s with an error of 0.75% over 25 dB of channel loss. To the best of our knowledge, these results represent the highest channel loss reported for secure quantum key distribution using the subcarrier wave approach. A passive unidirectional scheme has been used to compensate for the polarization dependence of the phase modulators in the receiver module, which resulted in a high visibility of 98.8%. The system is thus fully insensitive to polarization fluctuations and robust to environmental changes, making the approach promising for use in optical telecommunication networks. Further improvements in secure key rate and transmission distance can be achieved by implementing the decoy states protocol or by optimizing the mean photon number used in line with experimental parameters.

 View at publisher’s website