<title>Optical wireless: a prognosis</title>

Wireless infrared communications

“…While such diffusers can achieve efficiencies of about 70%, they typically yield a Lambertian radiation pattern, offering the designer little freedom to tailor the source radiation pattern. Computergenerated holograms [29] offer a means to generate customtailored radiation patterns with efficiencies approaching 100%, but must be fabricated with care to insure that any residual image of the LD emission aperture is tolerably weak.…”

LED location beacon system based on processing of digital images

“…Smyth et al [9] review the application of optical free space link for future broadband network. Long (0.5-5 km) and short (< 500 m) external and internal system are discussed.…”

Atmospheric effects on Quaternary polarization encoding for free space communication

“…Some of them are optical methods involving light, wherein different polarization or phase states of light are mapped to DiBITs [2,3]. However, when such methods are operated in free space communication protocols, concern has to be taken about the fact that atmospheric phenomena such as fog and smoke cause multiple scattering of the light, leading to a depolarization [4,7,8,9,10]. In additon, as we show in this communication, the depolarization behaviour is different for different encodings, adding additional difficulty, which is peculiar to M-ary encodings.…”