SoftBank and Nokia conducted a field trial testing three generations of passive optical network (PON) technology with different communication speeds.

The demo leveraged gigabit passive optical network (GPON), 10-gigabit symmetrical passive optical network (XGS-PON), and 50-gigabit passive optical network (50G-PON) on the same optical fiber using a single optical transceiver.

GPON and XGS-PON signals were superimposed over existing subscriber optical fibers connected to commercial network equipment with a 100 Gb/s optical signal, marking what was claimed to be Japan’s first successful demonstration of 100G-PON superposition.

Nokia supplied a multirate optical transceiver optical transceiver, which supports GPON, XGS-PON, and 50G-PON from a single transceiver and connection port. The equipment was not named by SoftBank, but is likely to be from the Nokia Lightspan OLT (optical line terminals) range.

SoftBank used a configuration in which 50G-PON was added on the same optical fiber while maintaining existing GPON and XGS-PON communication, with the speed and capacity increased in stages according to communication demand.

The intended model would continue serving existing GPON and XGS-PON customers while allowing 50G-PON to be introduced flexibly for particular customers or locations. The emphasis is on drawing more capability out of the installed fiber asset rather than re-architecting the optical distribution network every time a new PON generation is introduced.

On the 100G side, SoftBank will continue to explore whether the tech will eventually be practical in an operational access network. The firm intends to investigate stability, achievable real-world throughput, transmission distance, the number of fiber splits, optical-signal loss, and whether the new signal interferes with existing PON technologies.

The demo is claimed to be the first field trial of its sort conducted in a commercial environment and framed as a response to expected traffic growth from generative AI, cloud services and high-definition video. SoftBank highlighted increasing upstream requirements as users send more images, video, and other data into cloud services.

It also expects downstream access capacity to increase, with optical access relevant for residential broadband, enterprise connectivity, and to aggregate or connect mobile networks.

The technology is also being tested elsewhere in the nation by fellow Japanese telecom giant NTT, whose all-photonic network efforts are powering research into hollow core fiber (HCF) use cases in conjunction with 100G-PON.

Beyond Japan, 100G-PON deployments have been tested by CableLabs using coherent passive optical network (CPON), with the firm stressing to this title coherent optics use helps reduce capital and operating costs behind such compute-heavy deployments.