The Emergence of

Power-Over-Fiber

Sept. 16, 2021


In addition to owning and operating an art academy and advocating for artists and teachers in the San Francisco Bay Area, I work as a sales and marketing professional in the telecommunications industry. My job is to primarily look for new trends in communications and sensing, particularly trends related to the rollout of 5G, 6G, and IoT technologies. Therefore, I spend a good chunk of time reading trade magazines and whitepapers. I recently came across an article in Cabling Installation & Maintenance (May/June 2021) titled "Is Copper in Fiber's Future?" by Kevin Paschal, which I would like to share my thoughts on.


With a non-technical writing style and easy-to-follow diagrams that even novices can understand, in his article, Kevin explains the evolution of powered telephony and the tradeoffs between copper and fiber optic cable for enabling modern day communications networks to run. Copper and fiber are traditionally used for providing data and power to low-power devices inside buildings, such as cameras, Wi-Fi access points, temperature and smoke sensors, physical access controls, telephones, etc. According to Kevin, fiber is better suited for data communications, whereas copper is better for transmitting power, and so he supports the use of a hybrid technology called Power-over-Ethernet, or PoE for short, which combines both fiber and copper wire into a single cable.


Since I work in the fiber optics industry, I am a proponent of using fiber to provide both power and data to the end-device and eliminating copper cable altogether. This would eliminate the need to install two different cable systems (fiber and PoE) inside buildings, and also enable building managers to build and maintain one grid instead of separate power and data grids.


Running straight fiber optic cable to the end-device to provide power is known as Power-over-Fiber, or PoF, and although the technology has been around for about three decades, it is a nascent field in our industry. PoF uses the photoelectric effect, or the same principle behind how solar panels works, to convert laser light into electricity using a photodetector. I will not go into detail here on this technology, but would like to briefly describe the work of Professor Motoharu Matsuura from the University of Electro-Communications in Tokyo.


In his whitepaper, "150-W Power-Over-Fiber Using Double-Clad Fibers," Professor Matsuura explains how he used a novel type of fiber optic cable, known as double-clad fiber, to successfully transmit not only data, but several watts of electrical power over a distance of one kilometer between a central office and a remote antenna unit. This is groundbreaking work, because, as with solar power technology, fiber optics technology is not very efficient at transmitting and converting laser light into electricity, especially over longer distances.


Traditionally, this job is left to copper cable, which is more efficient at transmitting power. Through his experiments, however, Professor Matsuura has demonstrated that there may be promise for using fiber optic cable to not only send data, but also effectively deliver power, to remote devices located inside and outside of buildings. If mass produced and commercialized, PoF will play a prominent role in the rollout of 5G, 6G, and IoT, because the number of low-power antenna units and other communication devices that require power is expected to increase dramatically.


Thanks for reading!