Design research and performance analysis of compound parabolic concentrators as optical antennas in visible light communication

In order to satisfy the need of visible light communication, compound parabolic concentrators are selected as the optical antennas because of their wide fields of view and high gains in small field of view. Their geometries and optical properties are introduced in order to design compound parabolic concentrators with different fields of view by TracePro. These compound parabolic concentrators are tested under different light source conditions. The distribution of the received power of the receiver which has been coupled with the compound parabolic concentrator, is obtained by a simulation. The obtained gain of compound parabolic concentrator proves that the compound parabolic concentrator works better when the light source has a Lambert radiation pattern than the case under a parallel light condition. The results illustrate that compound parabolic concentrator is suitable to serving as an optical antenna for visible light communication. And it also shows that the smaller the field of view, the greater the gain is. Under the condition of simulation in this paper, a compound parabolic concentrator with 10° field of view could realize a gain of 22.88, which is 31% lower than the theoretical gain because of the effect of its position relative to the light source. On this basis, the model of a visible light communication system is established in a room with a size of 5 m×5 m×3 m. By using a compound parabolic concentrator with a field of view of 60° as an optical antenna, the simulation results show that the average received power is increased by 4.29 dBm for the directed light from light emitting diodes, and by 4.77 dBm with the reflected light being included. And the average received power is increased by 11.2% when the reflected light is considered.