Dual-aperture hologram receiver for visible light communications

To optimize the performance of visible light communication (VLC) systems it is important that a VLC receiver has both a carefully designed field of view (FOV) which excludes light from unwanted directions and optical filtering to block unwanted wavelengths. The new dual-aperture hologram receiver consists of two parallel opaque layers each with a transparent aperture and a volume hologram placed below the second aperture. The dual apertures ensure that only light from specific directions reaches the hologram. The hologram provides wavelength selectivity and additional directivity. Analytical and simulation results show how the FOV of the new dual aperture hologram receiver depends on the dimensions of the aperture structure, and the position and size of the receiver photodiode, and how the optical bandwidth depends on the design of the hologram. Proof of concept experiments confirm the performance of the receiver. Major advantages of the new receiver are its compact structure suitable for incorporation in smartphones and its ease of manufacture.