Red/green/blue LD mixed white-light communication at 6500K with divergent diffuser optimization

Y.-F. Huang, Y.-C. Chi, M.-K. Chen, Din-ping Tsai, D.-W. Huang, G.-R. Lin

Research output: Journal article publicationJournal articleAcademic researchpeer-review

21 Citations (Scopus)


© 2018 Optical Society of America under the terms of the OSA Open Access Publishing AgreementEnabling laser white-lighting at a correlated color temperature (CCT) of 6500K with the use of only red/green/blue (RGB) tri-color laser diodes (LDs) is demonstrated, which can further perform wavelength division multiplexing (WDM) communication with a high-spectral-usage 16 QAM-OFDM data stream at 11.2 Gbps over 0.5 m. The sampling rate of encoded data is optimized to avoid the aliasing effect and to effectively amplify the signal with high on/off extinction and modulation depth. Proper oversampling can decrease the peak-to-average power ratio (PAPR) of the OFDM data and filter out unwanted noise. There are also six different diffusers used to diverge the white-light mixed by the RGB LD beam. By analyzing the color-casting transmittance, surface roughness, CCT uniformity, divergent angle of the diffuser, and the data transmission capacity, the frosted glass (FG2.8) diffuser with high transmittance diverges the white light with the divergent angle of ± 20° and supports the highest data rate of 14 Gbps over 0.5 m. To fit the day-light CCT, the blue LD power at an optimized bias current is further attenuated with a 0.6-optical density filter for reducing CCT from 100000K to 6500K; however, such an adjustment also degrades the SNR ratio to sacrifice the achievable data rate of the blue LD. The polycarbonate (PC1.5) diffuser with proper surface roughness diverged white-light exhibits the best CCT uniformity and a divergent angle of ± 30° but supports a data rate of only 6.4 Gbps over 0.5 m. The poly (methyl methacrylate) PMMA1.5 diffuser scatters the white light with the largest angle of ± 40°; however, the data rate also decreases to 4.8 Gbps over 0.5 m.
Original languageEnglish
Pages (from-to)23397-23410
Number of pages14
JournalOptics Express
Issue number18
Publication statusPublished - 3 Sep 2018
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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