Feasibility Study of Optical Wireless Technology in Data Center Network

We investigate the scalability and performance of a novel optical wireless data center network (OW-DCN) based on passive diffractive optics and fast tunable transmitters. The proposed OW-DCN architecture consists of two parallel inter- and intra- cluster networks to implement a flat communication between the top of racks within the DCN with at most two hops. The proposed DCN operation, the transmission performance and the scalability have been experimentally demonstrated and assessed for different modulation formats (NRZ-OOK and PAM4) with different sizes of DCN. A DCN with 8 x 8 racks shows 20Gbit/s OOK error free transmission with a power penalty of only 1dB compared to the B2B performance. For a 16 x 16 racks DCN, experiment indicates 16Gbit/s PAM4 transmission at FEC-limit of BER < 2 x 10(-3). Moreover, scalability investigations of the proposed DCN architecture with optimized passive optics indicate that a 32 x 32 racks DCN with spectral band around 1 nm per link is feasible.