Optics, Photonics & Laser

Sergei A. Kozlov, Doctor of physical and mathematical sciences, professor, dean of the faculty of photonics and optoinformatics, a renowned expert in nonlinear optics and laser physics of ultrashort pulses. In 1982 he graduated with honors from the Department of Quantum Electronics Engineering Physics Faculty LITMO. 1982-1985 years. - Graduate student of quantum electronics. He received degrees as Candidate of Physical and Mathematical Sciences (1986), associate professor in the Department of Physics (1992), Doctor of Physical and Mathematical Sciences (1997), a professor in the department of Photonics and optoinformatics. He works in Saint Petersburg State University of Information Technologies Engineer, assistant, Associate professor, Professor, Department of Physics. Dean of the Faculty of photonics and optoinformatics, supervisor of the department of Photonics and optoinformatics, head of the International Institute of Photonics and optoinformatics. He was awarded the Medal of A. Lebedeva, the medal "In memory of the 300th anniversary of St. Petersburg". He is Chairman of the Dissertation Council D 212.227.02 and also the winner of the Lenin Komsomol Prize for Science and Technology.

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 [1]. 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. The system was used in deployment of ITMO University quantum network in Saint Petersburg, Russia, where a polarization independent subcarrier wave quantum key distribution operation with sifted bitrate 250 kbit/s was for the first time demonstrated in metropolitan telecommunication network channel composed of standard SMF-28e fibers with 1.5 dB loss.

S.A.Moiseev has completed his PhD at the age of 30 years in Kazan Physical-Technical Institute (KPTI) of Russian Academy of Science (Russia) and then defended Dr.Sci (Habilitation in Russia) in 42 years in Kazan State University (Russia). He is a professor of Kazan National Research Technical University (KNRTU), director of Kazan Quantum Center (KNRTU) focusing on the elaboration of optical quantum memory and quantum communications and chief of lab. Quantum memory and informatics in KPTI. He have proposed and theoretically elaborated the photon echo approach for realization of optical quantum memory, proposed a four-wave mixing for coherent control of stationary and slow light pulses. Recently S.A. Moiseev proposed a transistor architecture for universal quantum computer. Published more than 100 papers in reputed journals. He was a guest editor of first special issue on quantum memory problems in Journal of Physics B: Atomic, Molecular & Optical Physics. 45, 120201 (2012), worked as invited professor researcher in the Universities of S.Korea, Canada, France, China.

Construction of optical quantum memory (QM) attracts a considerable attention due to promising applications in elaboration of various quantum information technologies. During the last decade, a number of fascinating experimental results have been obtained along this way that indicates to the feasibility of achieving this goal in the nearest future. The photon echo approach promises a number of convenient protocols for storage of multi-mode light fields such as CRIB, GEM, AFC, ROSE –protocols. Moreover, these protocols can be adopted and modified for different types of light-atom interactions. In particular, off-resonant Raman interaction of light fields with atomic systems greatly extends experimental conditions for realization of the photon echo QM schemes that could be especially important for nanooptical implementations. In this report, we discuss a number of such variants for the photon echo QM. We analyze the properties of propagating and optical cavity schemes where we focus our attention on the broadband and multi-color storage. Special attention will be devoted to the role of time-reversal dynamics in the light-atom interaction as a robust condition for high quantum efficiency and fidelity in the light storage and quantum processing of the photon states. Finally, we discuss a potential realization of the studied photon echo schemes in the planed experiments on the inorganic crystals doped by rare-earth ions and potential application of these schemes for quantum repeaters.

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 [1]. 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. The system was used in deployment of ITMO University quantum network in Saint Petersburg, Russia, where a polarization independent subcarrier wave quantum key distribution operation with sifted bitrate 250 kbit/s was for the first time demonstrated in metropolitan telecommunication network channel composed of standard SMF-28e fibers with 1.5 dB loss.