A distributed optical fiber sensing system for data center thermal monitoring

Temperature monitoring and regulation is a critical aspect of data center administration. Currently, conventional discrete transistor-based thermal sensing systems are widely used for this purpose, which requires a discrete device for each temperature measurement in the special domain. This leads to an increase in both complexity and cost as the data center grows in scale. This manuscript describes a real-time multiplexed optical fiber thermal sensing system for data center applications which simultaneously measures thousands of discrete points along the length of the fiber under test. This system allows for real-time thermal monitoring of several hundred servers with a spatial resolution of 1 cm, a temperature resolution of <1 °C, and a system update rate of 1 Hz. Temperature inside of individual servers and the ambient room temperature outside the racks can be simultaneously monitored in real time using a single optical fiber probe. To investigate this concept, a pilot experiment is presented which monitored the dynamic server temperature distribution using the proposed fiber sensing system. Temperature data recorded using built-in thermal sensors within the CPU of the server under test were simultaneously recorded and compared to measurements made. In order to induce a temperature change within the server, a computationally intensive task was undertaken during temperature testing. Both methods of temperature measurement demonstrated similar trends, indicating that the proposed multiplexed optical fiber-based system has substantial potential as a scalable method of distributed data center temperature monitoring.