A Scalable VCSEL-Array Optical Wireless Transmitter With Experimental Multi-Beam Prototype

A 5×5 VCSEL array-based optical wireless communication multi-beam transmitter is designed and simulated. Each element of the array addresses a separate spatial attocell. A microlens-array based homogenizer achieves uniform coverage at the receiver plane from each multi-mode VCSEL output. 1 m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> total coverage is achieved with each attocell covering an area of 400 cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at a range of 3 m. For a proof-of-concept demonstration a 1×3 channel VCSEL array-based transmitter prototype is experimentally tested. The performance is verified by demonstrating three channels achieving ∼ 0.12 mW/m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> uniform power with negligible optical interference to adjacent attocells (<-14 dB). With a simple receiver design using low cost, off-the-shelf components, each channel of the transmitter achieves ∼10 Gb/s throughput using OFDM within 7 cm lateral range and > 4 Gb/s within 12 cm lateral range at 3 m. The transmitter meets eye-safety restrictions and could be scaled to 250 Gb/s aggregate data rate by employing all 25 VCSELs with independent OFDM modulation.