Browsing by Author "Ng, Tien Khee"

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4-Gbit/s visible light communication link based on 16-QAM OFDM transmission over remote phosphor-film converted white light by using blue laser diode
(2015-12-28)
Retamal, Jose Ramon Duran
;
Oubei, Hassan Makine
;
Janjua, Bilal
;
Chi, Yu-Chieh
;
Wang, Huai-Yung
Visible Light Communication (VLC) as a new technology for ultrahigh-speed communication is still limited when using slow modulation light-emitting diode (LED). Alternatively, we present a 4-Gbit/s VLC system using coherent blue-laser diode (LD) via 16-quadrature amplitude modulation orthogonal frequency division multiplexing. By changing the composition and the optical-configuration of a remote phosphor-film the generated white light is tuned from cool day to neutral, and the bit error rate is optimized from 1.9 x 10(-2) to 2.8 x 10(-5) in a blue filter-free link due to enhanced blue light transmission in forward direction. Briefly, blue-LD is an alternative to LED for generating white light and boosting the data rate of VLC. (C) 2015 Optical Society of America
4-Gbit/s visible light communication link based on 16-QAM OFDM transmission over remote phosphor-film converted white light by using blue laser diode
(2015-12-28)
Retamal, Jose Ramon Duran
;
Oubei, Hassan Makine
;
Janjua, Bilal
;
Chi, Yu-Chieh
;
Wang, Huai-Yung
Visible Light Communication (VLC) as a new technology for ultrahigh-speed communication is still limited when using slow modulation light-emitting diode (LED). Alternatively, we present a 4-Gbit/s VLC system using coherent blue-laser diode (LD) via 16-quadrature amplitude modulation orthogonal frequency division multiplexing. By changing the composition and the optical-configuration of a remote phosphor-film the generated white light is tuned from cool day to neutral, and the bit error rate is optimized from 1.9 x 10(-2) to 2.8 x 10(-5) in a blue filter-free link due to enhanced blue light transmission in forward direction. Briefly, blue-LD is an alternative to LED for generating white light and boosting the data rate of VLC. (C) 2015 Optical Society of America
4.8 Gbit/s 16-QAM-OFDM transmission based on compact 450-nm laser for underwater wireless optical communication
(2015-09-07)
Oubei, Hassan M.
;
Duran, Jose R.
;
Janjua, Bilal
;
Wang, Huai-Yung
;
Tsai, Cheng-Ting
We experimentally demonstrate an underwater wireless optical communications (UWOC) employing 450-nm TO-9 packaged and fiber-pigtailed laser diode (LD) directly encoded with an orthogonal frequency division multiplexed quadrature amplitude modulation (QAM-OFDM) data. A record data rate of up to 4.8 Gbit/s over 5.4-m transmission distance is achieved. By encoding the full 1.2-GHz bandwidth of the 450-nm LD with a 16-QAM-OFDM data, an error vector magnitude (EVM) of 16.5%, a signal-to-noise ratio (SNR) of 15.63 dB and a bit error rate (BER) of 2.6 x 10-3, well pass the forward error correction (FEC) criterion, were obtained. (C) 2015 Optical Society of America
Going beyond 4 Gbps data rate by employing RGB laser diodes for visible light communication
(2015-07-13)
Janjua, Bilal
;
Oubei, Hassan M.
;
Retamal, Jose R. Duran
;
Ng, Tien Khee
;
Tsai, Cheng-Ting
With increasing interest in visible light communication, the laser diode (LD) provides an attractive alternative, with higher efficiency, shorter linewidth and larger bandwidth for high-speed visible light communication (VLC). Previously, more than 3 Gbps data rate was demonstrated using LED. By using LDs and spectral-efficient orthogonal frequency division multiplexing encoding scheme, significantly higher data rates has been achieved in this work. Using 16-QAM modulation scheme, in conjunction with red, blue and green LDs, data rates of 4.4 Gbps, 4 Gbps and 4 Gbps, with the corresponding BER/SNR/EVM of 3.3 x 10(-3)/15.3/17.9, 1.4 x 10-3/16.3/15.4 and 2.8 x 10(-3)/15.5/16.7 were obtained over transmission distance of similar to 20 cm. We also simultaneously demonstrated white light emission using red, blue and green LDs, after passing through a commercially available diffuser element. Our work highlighted that a tradeoff exists in operating the blue LDs at optimum bias condition while maintaining good color temperature. The best results were obtained when encoding red LDs which gave both the strongest received signal amplitude and white light with CCT value of 5835K. (C) 2015 Optical Society of America
Wireless optical transmission of 450 nm, 3.2 Gbit/s 16-QAM-OFDM signals over 6.6 m underwater channel
(2016)
Oubei, Hassan M.
;
Duran, Jose R.
;
Janjua, Bilal
;
Wang, Huai-Yung
;
Tsai, Cheng-Ting
We experimentally realized a gigabit underwater wireless optical communication system using commercially available 450 nm blue laser diode. By implementing 16-QAM-OFDM modulation, we achieved data rate of 3.2 Gbit/s with a BER of 6.83x10(-4) over 6.6 m channel.