  Due to the emergence of new paradigms and services such as 5G/6G, IoT, and
more, current deployed wired Data Center Networks (DCNs) are not meeting the
required performance metrics due to their limited reconfigurability,
scalability, and throughput. To that end, wireless DCNs using technologies such
as Optical Wireless Communication (OWC) have become viable and costeffective
solutions as they offer higher capacity, better energy efficiency, and better
scalability. This paper proposes an OWC-based spine and leaf DCNs where the
leaf switches are enabled with OWC transceivers, and the spine switches are
replaced by Access Points (APs) in the ceiling connected to a backbone network.
The APs are interconnected through a Passive Optical Network (PON) that also
connects the architecture with upper network layers. An Infrared (IR) OWC
system that employs Wavelength Division Multiplexing (WDM) is proposed to
enhance the DCN downlink communication. The simulation (i.e., channel modeling)
results show that our proposed data center links achieve good data rates in the
data center up to 15 Gbps. For the PON, Arrayed Waveguide Grating Routers
(AWGRs) that enable WDM are proposed to connect the APs. We evaluate the
performance of the considered architecture in term of its power efficiency
compared to traditional spine and leaf data centers. The results show that the
OWC-enabled DCN reduces the power consumption by 42% compared to traditional
the spine and leaf architecture.
