Optical Filter-Less WDM for Visible Light Communications Using Defocused MIMO

Andrew Burton, Petr Chvojka, Paul Anthony Haigh, Zabih Ghassemlooy, Stanislav Zvánovec*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)
8 Downloads (Pure)


This paper experimentally investigates, for the first time, a new wavelength-division multiplexing-based visible light communications link based on a defocused non-imaging multiple-input multiple-output (MIMO), which removes the need for tuned optical bandpass filters paired with each receiver. The proposed system is based on using the natural diversity of the individual light emitting diodes (LEDs) within a single light source to generate an H-matrix, which is independent of spatial diversity. We show that, by transmitting K-independent sets of non-return to zero on-and-off keying signals on separate wavelengths, the received superposed symbols can be demultiplexed. The non-imaging MIMO diversity is achieved by considering the power-current characteristics of the light emitting diode, the responsivity of the photodetector array, and the defocused beam spot. The system is empirically verified for K = 3 using red, green, and blue LEDs with Q-factors of 7.66, 7.69, and 4.75 dB, respectively.
Original languageEnglish
Article numbere1065
Number of pages8
Issue number9
Early online date30 Apr 2021
Publication statusPublished - 1 May 2021


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