High Power Eye-Safe Optical Wireless Gigabit Link Employing a Freeform Multipath Lens

This work experimentally demonstrates for the first time the practical feasibility of a freeform multipath lens (MPL) for optical wireless communications (OWC). The MPL is able to increase the eye safety laser power limit. Our transmitter is laser class 1M and features 190 mW optical output. We transmit 1.289 Gbit/s on-off keying (OOK) data and achieve a bit error ratio (BER) of 10⁻¹⁰ for an optical receiver power of −31.2 dBm. The link range is more than 5 m, depending on the targeted BER. We discuss the pros and cons of MPLs and compare them with diffusers.