Ryu Laboratory (Ryu Lab) has just started research on April 2016 immediately after S. Ryu joined Meiji University.
Ryu Lab is aiming at research on optical communication systems, communication networking, and related optical measurement techbnology.
Ryu Lab is located at Nakano Campus, Meiji University near JR Nakano station in central Tokyo.
We are doing research on the following topics.
1. Optical wireless communication systems
２. Long-haul coherent optical fiber communication systems
４．Optical measurement techbnology
Mobile communication operators are facing heavy traffic demand, which has
forced the use of the Wi-Fi systems to provide mobile operators with additional
However, traffic demand is still increasing day by day. Even if we use the Wi-Fi systems, we frequently experience shortage of traffic capacity in the mobile communication systems in large traffic areas.
Optical wilreless communication (OWC) systems are attractiing much attention recently since the systems have possibilities to provide us with much traffic capacities by virtue of inherent high frequency of light. Recently, the OWC is sometimes referred to "Li-Fi" that is a new word coming from "Wi-Fi".
However, the OWC systems have essential problems; the systems are sensitive to the obstacles between a light source and a receiver since the OWC systems uses lightwave. To solve the above mentioned problem, we are now doing research on diversity systems in which multiple transmitters and receivers cooperate to establish stable communication channel. Diversity systems will play an important role in realization of the OWC systems.
Research on long-haul high capacity systems has been improved significantly recetly. Using the present state-of-the-art digital coherent optical communication systems technology, 100-Gbit/s per wavelength using QPSK format and 200-Gbit/s per wavelength using 16QAM format have been commercialized. Coherent optical communication systems use optical phase of light to carry data streams.
Coherent optical communication systems using optical phase modulation is essentially susceptible to optical phase noise caused by, e.g., optical fiber nonlinearities. Optical phase noise have not been paid so much attention in traditional optical communication systems since the systems just used 'intensity modulation' of light.
We are doing research on optical phase noise caused in the fibers to clarify the effect of the phase noise characteristics on the transmission performance.
Room 1207, 1208
4-21-1, Nakano, Nakano-ku
Tokyo 164-8525, Japan