Net Journal 2
The cutting edge of next-generation optical network technology led by nanophotonics
Masanori Koshiba, Doctor of Engineering,
Professor of the Graduate School of Information Science and Technology, Hokkaido University,
Division of Media and Network Technologies's Research Group of Information Communication Systems
Ubiquitous society - what's next?
---- Broadband has recently spread to general households, and the term "photonics" is becoming established. What kind of research is currently conducted at the cutting edge of optical network technology?
Dr. Koshiba: Since Japan has conventionally played a leading role in the research and development of optical communications, its industry, educational institutions and administration all have world-class technical capabilities. Hokkaido University has also made many achievements in developing advanced technologies in the field of photonics. This foundation is currently being built on in the field of information through the Graduate School of Information Science and Technology, and research toward the realization of a next-generation optical network is being promoted from a comprehensive point of view, including communications, electronics and information technology.
Optical networks are an essential technology in ubiquitous society, and FTTH service to spread optical fibers to general households is also expanding dramatically. There is, however, a major problem in that the further spread of optical networks in the future may cause a huge increase in the amount of information distributed on the net and possibly even exceed Moore's Law. While the optical fibers currently in use are capable of terabyte transmission (i.e. transmission of 1 trillion optical pulses per second) by wavelength division multiplexing (Ex. 1), the capacity of the fiber is used to its limit. It is also expected that the electric signals used to process switching, routing and other network transfer functions will not be able to keep up with the speed of optical signals in the future.
Against this background, a new optical technology using photonic crystals (Ex. 2) is attracting attention as a key method of speeding up next-generation optical networks. While photonic crystals themselves are present in the natural world, nano-sized photonic crystals can now be produced artificially with the dramatic advances in nanophotonics technology supported by the recent evolution of nanotechnology. This is expected to lead to the realization of various optical devices, including entirely new optical fibers with properties that cannot be realized by conventional optical fibers and microminiature optical circuits.