Physical Layer Security for FSO-based Data Center

Wireless data center network has recently received a lot of academic attention. Relevant studies have shown that Free Space Optical (FSO) technology can bring flexible topologies, high speed transmission and low energy consumption to data centers. However, it can also make the cloud data broadcast in the data center space. Some work has shown that outdoor FSO channel is vulnerable to eavesdropping attacks due to the combined attenuation effects of atmospheric turbulence and long distance transmission. Unfortunately, it is not clear the security of FSO channel in data centers and there are few studies discussing it. We study the physical layer security of FSO link in the data center indoor scenario. A suitable tapping channel model was given based on the viable mechanism of eavesdrop communication in data center. We also numerically simulate the FSO eavesdropping channel in short distance and study the impact of the relevant factors on probability of secrecy capacity. The results show that in data centers, only path attenuation of FSO also poses a channel eavesdropping risk. Under certain conditions, the distance of a few tens of meters combined with the use of shorter wavelengths can result in serious channel security risks. At the same time, the use of long wavelengths or special window wavelengths with small attenuation of FSO in FSO-based data centers has significantly improved channel security.