Design and evaluation of optical antenna module suitable for Radio-on Free-Space Optics link system for ubiquitous wireless

We present initial results on research and development of an optical antenna module suitable for Radio-on Free-Space Optics (RoFSO) links. This new optical communication system is envisaged to be an effective means of realizing a ubiquitous society and therefore eliminating the digital divide. The RoFSO system is a trial system applying Radio on Fiber (RoF) technology for transmission through free space. Based on the results of research of next generation high-speed free-space optical communication system conducted in the past two years at Waseda University, we have developed an optical antenna module with efficient laser receiving characteristics as well as simple adjustment. The tracking system adopts two phases including rough tracking by the beacon light at 0.85 μm wavelength and fine tracking using communication light at 1.55 μm wavelength to improve compensation precision for the atmospheric turbulence at the time of beam propagation. We present results on the evaluation of performance characteristics (static characteristics) of the separate functions for RoFSO antenna module we have developed and confirmed the coupling efficiency and fine tracking characteristics which were set as goals at the beginning.