Ultrahigh-Speed Optical Communication Group

Group Web Site

[ Professor ]Toshihiko Hirooka
Ultrahigh-Speed Optical Communication

[ Associate Professor ] Keisuke Kasai

Research Activities

Optical communication systems have evolved as a core technology of the ICT infrastructure and become widely used in society. This widespread deployment has been enabled by the progress made on light sources, transmission media, and signal processing, and by taking advantage of their high-speed and broadband operation. In the future, further innovation is expected that will realize flexible communication links capable of accommodating massive increases in the amount of information at any time, and transmitting it anywhere, and between any devices. In this laboratory, we aim at establishing ultrahigh-speed, large-capacity, highly secure and resilient optical communication technologies that can even be integrated with wireless communication by taking ultimate advantage of the coherence of lightwaves. We also intend to develop functional optical systems capable of handling such transmissions with extremely high energy efficiency.

Optical Signal Processing (Assoc. Prof. Hirooka)

We are engaged in the development of all-optical technologies using nonlinear optical effects by taking advantage of ultrafast optical properties, where optical signals are processed without the need to convert them into the electrical domain. Specifically, we are developing femtosecond pulse compression, pulse shaping, optical demultiplexing, and distortion elimination techniques, which are indispensable for realizing ultrahigh-speed OTDM transmission exceeding terabit/s.

Research topics

  • Distortion elimination technique using time-domain optical Fourier transformation
  • All-optical signal processing using nonlinear optical effects and their application to ultra-high-speed OTDM transmission
Experiment on ultrahigh-speed optical transmission
2048 QAM coherent optical signal (left) and cross section of 19-core fiber (right)