Browsing by Author "Chen, Hsiang-Yu"

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450-nm GaN laser diode enables high-speed visible light communication with 9-Gbps QAM-OFDM
(2015-05-18)
Chi, Yu-Chieh
;
Hsieh, Dan-Hua
;
Tsai, Cheng-Ting
;
Chen, Hsiang-Yu
;
Kuo, Hao-Chung
A TO-38-can packaged Gallium nitride (GaN) blue laser diode (LD) based free-space visible light communication (VLC) with 64-quadrature amplitude modulation (QAM) and 32-subcarrier orthogonal frequency division multiplexing (OFDM) transmission at 9 Gbps is preliminarily demonstrated over a 5-m free-space link. The 3-dB analog modulation bandwidth of the TO-38-can packaged GaN blue LD biased at 65 mA and controlled at 25 degrees C is only 900 MHz, which can be extended to 1.5 GHz for OFDM encoding after throughput intensity optimization. When delivering the 4-Gbps 16-QAM OFDM data within 1-GHz bandwidth, the error vector magnitude (EVM), signal-to-noise ratio (SNR) and bit-error-rate (BER) of the received data are observed as 8.4%, 22.4 dB and 3.5 x 10(-8), respectively. By increasing the encoded bandwidth to 1.5 GHz, the TO-38-can packaged GaN blue LD enlarges its transmission capacity to 6 Gbps but degrades its transmitted BER to 1.7 x 10(-3). The same transmission capacity of 6 Gbps can also be achieved with a BER of 1 x 10(-6) by encoding 64-QAM OFDM data within 1-GHz bandwidth. Using the 1.5-GHz full bandwidth of the TO-38-can packaged GaN blue LD provides the 64-QAM OFDM transmission up to 9 Gbps, which successfully delivers data with an EVM of 5.1%, an SNR of 22 dB and a BER of 3.6 x 10(-3) passed the forward error correction (FEC) criterion. (C) 2015 Optical Society of America
Phosphorous Diffuser Diverged Blue Laser Diode for Indoor Lighting and Communication
(2015-12-21)
Chi, Yu-Chieh
;
Hsieh, Dan-Hua
;
Lin, Chung-Yu
;
Chen, Hsiang-Yu
;
Huang, Chia-Yen
An advanced light-fidelity (Li-Fi) system based on the blue Gallium nitride (GaN) laser diode (LD) with a compact white-light phosphorous diffuser is demonstrated for fusing the indoor whitelighting and visible light communication (VLC). The phosphorous diffuser adhered blue GaN LD broadens luminescent spectrum and diverges beam spot to provide ample functionality including the completeness of Li-Fi feature and the quality of white-lighting. The phosphorous diffuser diverged white-light spot covers a radiant angle up to 120 degrees with CIE coordinates of (0.34, 0.37). On the other hand, the degradation on throughput frequency response of the blue LD is mainly attributed to the selffeedback caused by the reflection from the phosphor-air interface. It represents the current state-ofthe- art performance on carrying 5.2-Gbit/s orthogonal frequency-division multiplexed 16-quadratureamplitude modulation (16-QAM OFDM) data with a bit error rate (BER) of 3.1 x 10(-3) over a 60-cm freespace link. This work aims to explore the plausibility of the phosphorous diffuser diverged blue GaN LD for future hybrid white-lighting and VLC systems.