Optical antenna design for indoor optical wireless communication systems

Abstract

SUMMARYIn the present paper, the design of the non-imaging totally internally reflecting concentrator family denominated optical antennas (OAs) is discussed, and its use for indoor optical wireless communication systems is explained. The lenses presented here can be designed to provide a prescribed angular response in order to limit the central wavelength shift in thin-film optical filters. They can also be designed for any specific field-of-view (FOV), which allows greater rejection of unwanted background radiation and higher gains. The use of a variety of optical filters to achieve a high signal-to-noise ratio at the receiver is described. Design methods and properties of different Optical Antennas are explained. Comparisons of size and performance of total internal reflection based concentrators with those based on dielectric hemispheres and compound parabolic concentrators (CPCs) are carried out. Finally different experimental results are presented.

A Genetic Algorithm Method for Optical Wireless Channel Control

“…Quasi-diffuse configurations employing multispot diffusion (MSD) and diversity receivers [4] improve the bandwidth and ambient noise rejection through the use of an array of photodetector's coupled to either, a single imaging lens [5], or several optical concentrators [6]. Implementation of automatic gain control (AGC) can compensate for the variations in received power at different positions within the room [7].…”

Recent developments in indoor optical wireless systems

“…The low level of optical power often present at the receiver makes the utilisation of optical concentrators to maximise light collection beneficial [29]. However, the high level of ambient light presents results in shot noise from the entire fieldof-view (FOV) of the optical concentrator plus detector combination.…”

“…Owing to the fact the FOV can be controlled, a higher optical gain can be achieved along with rejecting more background illumination. Recently, another alternative has been presented in the form of a three dimensional dielectric totally internally reflecting concentrator or optical antenna which also uses a planar optical filter between the concentrator and the detector, but, unlike the CPC, it can have a variety of entrance aperture shapes, giving it a smaller size and the ability for higher optical gain compared to the traditional CPC [29,40].…”

Multi-user indoor optical wireless communication system channel control using a genetic algorithm

“…Quasi-diffuse configurations, employing multispot diffusion (MSD) and diversity receivers [5], ameliorate the bandwidth and ambient noise rejection through the use of an array of photodetectors coupled to either a single imaging lens [6], or several optical concentrators [7]. Modulation techniques, such as trelliscoded pulse-position modulation [8], and amplitude shift keying digital demodulation [9], are capable of overcoming the effects of intersymbol interference (ISI), and cyclostationary noise from fluorescent lamps [3], respectively.…”