NTT and Kitami Institute of Technology have succeeded for the first time in the world in supplying more than 1 watt of power to an unpowered point more than 10 kilometers away while maintaining high speed and good communication quality using a single communication optical fiber.

In addition to making it possible to provide high-speed optical communications to all areas where optical communications have not yet been explored, including non-electrified areas, it is also expected to be possible to establish communications using optical fiber as an emergency response in the event of a loss of power supply during a disaster.
The multi-core optical fiber (MCF) used this time is the same thinness as existing optical fibers, and each core has the same transmission characteristics as existing optical fibers, so it can be used for normal optical communication (optical communication that does not require optical power supply). It can also be used in combination with existing transmission equipment. Furthermore, since each core can be used independently (without optical signal interference between cores), any core can be assigned for power supply, communication, or both.

In order to maximize the amount of optical power supplied, a light source with a wavelength of 1550 nanometers is input to the four cores. Furthermore, by using two of the four cores and assigning uplink and downlink signals with a wavelength of 1310 nanometers to each core, bidirectional optical communication is realized. It is also possible to set up two sets of two-core combinations, making it possible to configure two independent communication systems.

Bidirectional optical communication with a transmission speed of 10 Gbit/s using self-power supply was also demonstrated. The transmission speed of 10 gigabits/second is the highest transmission speed of optical communication currently available to general users. In this study, they investigated the configuration of one uplink and downlink system with two cores, and confirmed good transmission characteristics after 14 kilometers of transmission.
Considering the product of transmission speed and transmission distance as an indicator of transmission performance in self-optical power supply transmission, they were able to achieve the world’s highest transmission performance of 140 Gbit/s/km.