Hybrid Laser-LED Transmitter With Closed-Loop Beam-Steering Control for Indoor Optical Wireless Communication

Ahmad, F and Sathisha, RN and Jyothsna, KM and Raghunathan, V (2022) Hybrid Laser-LED Transmitter With Closed-Loop Beam-Steering Control for Indoor Optical Wireless Communication. In: Journal of Lightwave Technology, 40 (12). pp. 3557-3566.

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Abstract

In this paper, we demonstrate a hybrid Laser-LED transmitter module for indoor optical wireless communication with closed-loop, non-mechanical beam steering capability. The hybrid transmitter module consists of a near infrared laser diode for data communication and white LED array for illumination, combined on a diffuser surface. Dual-axis non-mechanical beam steering of the laser beam is implemented using two off-centered liquid lenses. The diffused laser beam directed towards the receiver is steered over an angular range of -7.6o to 7.6o (-1.7o to 2.6o) along the horizontal (vertical) axes spanning -200 to 200 mm (-44 to 67 mm) at the receiver placed 1.5-meter from the transmitter. M-QAM/OFDM in combination with adaptive bit-and power-loading is utilized to achieve a total data throughput of 5.15 Gbps for the diffused laser beam with steering. Laser intensity levels as measured at the receiver plane are kept below the maximum permissible exposure limit for indoor usage across the entire beam steering range. Closed-loop beam steering is also demonstrated by scanning the transmitted laser beam horizontally, measuring the signal strength using a low bandwidth photodetector and locking the laser beam to the receiver position for data-communication. Such hybrid transmitters offer the benefit of decoupling the data communication and illumination requirements of the indoor optical link, thereby tailoring the individual light emitter's performance to specific use-case. © 1983-2012 IEEE.

Item Type:	Journal Article
Publication:	Journal of Lightwave Technology
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to the Institute of Electrical and Electronics Engineers Inc.
Keywords:	Laser beams; Lenses; Locks (fasteners); Optical transmitters; Visible light communication, Beam-steering; Closed-loop; Data-communication; Hybrid lasers; Indoor optical wireless communications; Lightemitting diode; Liquid lens; Measurement by laser beam; Optical-wireless communications; Orthogonal frequency-division multiplexing, Infrared devices
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	21 Sep 2022 09:44
Last Modified:	21 Sep 2022 09:44
URI:	https://eprints.iisc.ac.in/id/eprint/76928

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