Any network is plagued by the inherent issue of slowing down when too many users are connected to it, because it takes the access network within about 20 km of the nearest station a long time to process the traffic. ETRI, however, has resolved this technical issue with the 25-Gbps technology called TiC-TOC.

ETRI announced that the essence of the technology is its fast optical reception module and the MAC technology. The fast optical reception module restores signals even with a weak optical input strength, while the MAC technology manages packets so that the traffic delivered via the optic fiber can be processed with ultra-low latency. These technologies mean that the current optic fiber used for Internet subscribers will not have to be replaced, and can be used to deliver huge amounts of data rapidly by boosting the laser speed tenfold. In other words, the capacity of the current network will be expanded and accelerated simply by improving the facilities, without having to install an additional optic fiber.

ETRI's researchers have integrated optical transmission and reception modules, an optical transceiver and the MAC technology into the line card, like one single board. Applying these technologies to the current OLT (Optical Line Terminal) installed at the station and ONU (Optical Network Unit) at apartment/commercial buildings will upgrade the system, enabling super-speed, ultra-low latency Internet services.

ETRI confirmed that the new technology was made possible by the channel bonding technology, low latency and band allocation technology, sensitivity and optical receiver module and optical transmission and reception technology that it had previously developed. Users of the current network used “assigned” and limited speed via one single channel, but this technology will expand the number of channels as well as the speed so that far more users can enjoy faster connection.

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Optical access technology with 25-Gbps
per wavelength simultaneously enabling
ultra-low latency services.

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ETRI will realize a new era of super-real
digital life.

ETRI worked on the development of a technology enabling network connection regardless of the user’s location in order to realize the super real digital life. The end result is the world's smallest optical transceiver and the related technology, which is capable of sending 200 GB of data per second via the mobile back hole network and the small metro network. This innovative technology will eliminate bottlenecks while greatly reducing power consumption and the equipment's footprint, which will be helpful in realizing the super-connected era.

ETRI has changed the modulation method which alters the luminous intensity for this technology. Instead of the current 2-phase NRZ method, which sends 1 bit at a time, ETRI's researchers selected the PAM-4 (Pulse Amplitude Modulation) to send 2 bits, boosting capacity. In addition, they managed to expand the range of the PAM-4 modulation method to 80 km (from the original 1 km) inside the data centers of major portal service providers.

Also based on this technology, ETRI developed an optical transmission/reception engine as an element technology to enable 400-Gbps in March of this year, thereby allowing 100,000 users to stream 1080p video on YouTube simultaneously. All of these technologies, when applied comprehensively, will resolve the issues of power consumption and the high cost of communication equipment, as its 1.5 times lower power consumption and 4 times higher density will allow a groundbreaking reduction of capex.

ETRI researchers are examining the semiconductor light source chips used in the 400 Gbps optical transmission/reception engine.