Achieving an all-optical connection between any wireless communication systems with optical fiber network is one of the ultimate goals of communication network design. An all-optical system providing seamless connection between free-space and optical fiber links by using free-space optical (FSO) communication technology suitable for next generation network has been developed. In order to realize this next-generation FSO communication system in which the transmitted light signal does not undergo any conversion thus achieving all-optical connection, it is necessary to develop a technology for tracking and focusing the free-space optical signal to a single mode fiber (SMF). The developed FSO system incorporates a fine pointing mirror (FPM) for high speed beam control and steering. This novel tracking method can suppress the beam intensity variations as a result of angle-of-arrival fluctuation (AOA) caused by atmospheric turbulence. This paper presents experimental results of a next-generation FSO system providing stable and reliable single channel transmission at 10 Gbps data rates as well as multiple channels using dense wavelength division multiplexing (DWDM). This kind of data rate is not possible to achieve using conventional FSO systems. The developed system can provide transmission capacity equivalent to optical fiber and from its design concept and configuration it is bit-rate and protocol transparent. Furthermore, we present research on Radio-on-FSO (RoFSO) system which is a combination of the developed next-generation FSO system and Radio over Fiber (RoF) technology. We demonstrate the possibility of utilizing this system for optical and radio frequency signals transmission. RoFSO technology is independent of the difference in the underlying physical layers for radio system or fiber system, but realizing fusion at the service level. The RoFSO technology is available to realize a universal platform for transparent forwarding various wireless services in a ubiquitous network environment.
ASJC Scopus subject areas
- コンピュータ サイエンスの応用