High-speed underwater communication with GaN blue LDs (Conference Presentation)

Gong-Ru Lin; Chih-Hsien Cheng; Yu-Fang Huang; Tsai-Chen Wu

doi:10.1117/12.2512662

5 March 2019 High-speed underwater communication with GaN blue LDs (Conference Presentation)

Gong-Ru Lin, Chih-Hsien Cheng, Yu-Fang Huang, Tsai-Chen Wu

Proceedings Volume 10918, Gallium Nitride Materials and Devices XIV; 1091821 (2019) https://doi.org/10.1117/12.2512662
Event: SPIE OPTO, 2019, San Francisco, California, United States

Abstract

To enable high-speed underwater wireless optical communication (UWOC) in tap-water and seawater environments over long distances, a 450-nm blue GaN laser diode (BLD) directly modulated by preleveled 16-quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) data was employed to implement its maximal transmission capacity beyond 10 Gbps. The proposed UWOC in tap water provided a maximal allowable communication bitrate increase from 5.2 to 12.4 Gbps with the corresponding underwater transmission distance significantly reduced from 10.2 to 1.7 m. Light scattering induced by impurities in seawater attenuates the blue laser power to degrade the transmission such that the BLD based UWOC enables a 16-QAM OFDM bitrate of up to 7.2 Gbps in seawater more than 6.8 m. To optimize the QAM-OFDM transmission, the sampling rate of the encoded data is compromised to avoid the aliasing and oversampling effects during waveform extraction procedure. The sampling rate is optimized to 3~5 times of the encoded data bandwidth for suppressing peak-to-average power ratio (PAPR). This improves the BLD based UWOC with 16-QAM OFDM data transmission at 14.8 Gbps over 1.7 m. Lengthening the seawater distance to 10.2 m only decreases the transmission data rate by 4 Gbps, Oversampling not only filters out background noise but also attenuates data amplitude to degrade transmission performance. With spectrally filtering out the sidelobes of each OFDM subcarrier, the allowable modulation bandwidth is greatly improved from 1.9 to 2.7 GHz, as the inter-carrier interference induced crosstalk between subbands is relieved to improve the SNR of the carried data with a raw data rate of up to 10.8 Gbps over 10.2 m in seawater channel.

Conference Presentation

Citation Download Citation

Gong-Ru Lin, Chih-Hsien Cheng, Yu-Fang Huang, and Tsai-Chen Wu "High-speed underwater communication with GaN blue LDs (Conference Presentation)", Proc. SPIE 10918, Gallium Nitride Materials and Devices XIV, 1091821 (5 March 2019); https://doi.org/10.1117/12.2512662

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
PRESENTATION

WATCH
PRESENTATION SAVE TO MY LIBRARY

GET CITATION

KEYWORDS

Gallium nitride

Orthogonal frequency division multiplexing

Modulation

Signal to noise ratio

Amplitude modulation

Data communications

Light scattering

Show All Keywords

Keywords/Phrases

Search In:

Publication Years