Development of a photodetector element that converts optical signals into electrical signals and a wavelength-variable light source element

Components for 5G communications networks have been developed.

The Electronics and Telecommunications Research Institute (ETRI) developed optical transmission and reception components using domestic technology. The existing transmission network was around 100G, but it was expanded by four times to 400Gbps.

ETRI has successfully demonstrated in a real environment a technology that can accommodate large-capacity data communications without additional installation of optical cables, even when traffic increases more than four times the current level for new network expansion, using components developed domestically.

There are two major optical transmission and reception components that ETRI has succeeded in developing. First, it developed a 400 Gbps optical receiver element that converts 400 Gbps optical signals into electrical signals and receives them, and a wavelength-tunable optical source element that is necessary to load electricity onto light in order to send electrical signals to optical communication networks.

The research team succeeded in developing an ultra-small component by developing the core components themselves and integrating them into an optical module. The developed coherent optical receiver is 3 cm x 1 cm in size, and the optical transmitter is 2 cm x 1 cm in size.

Accordingly, in the future, these technologies will be modularized into optical transmitters and receivers and used as repeaters for optical communications. These systems are expected to be installed in each city, especially in large cities with heavy traffic.

ETRI explained that these systems will be installed in the core networks or metro networks of mobile carriers in the future to effectively control traffic. In the future, this technology is expected to be implemented by optical transmission equipment manufacturers through optical transceiver manufacturers and then commercialized in earnest by telecommunications carriers.

The research team first created a 400Gbps electrical signal using a signal generator in Laboratory 4 of the ETRI Research Institute last month to confirm transmission. They successfully transmitted the created signal by putting it on light and sending it to Seoul through an optical fiber network, and then transmitting it back and forth to Daejeon.

ETRI's successful round-trip transmission test lasted a total of 510 km and used the Future Network Leading Test Network (KOREN) operated by the National Information Society Agency.

The research team said that with this technology development, existing optical communications had to be expanded by laying additional optical cables, but ETRI succeeded in developing a component technology that solves this problem by simply replacing the optical transmission and reception equipment using existing optical cables without the need for additional optical cable installation costing hundreds of billions of won. They said that this is the most effective in terms of not only economic benefits but also time and physical efficiency.

In addition, this technology is a next-generation optical network core technology that can control and manage transmission capacity, modulation method, and wavelength through software to provide communication services suitable for user needs such as transmission distance and communication quality. It has a great effect in increasing efficiency and reducing costs because there is no need to replace hardware to change transmission capacity.

Kim Jong-hoe, head of the Optical Communication Components Research Group at ETRI, said, “The optical components we developed are price competitive because they use low-cost materials such as silica and polymer, and in addition to 400 Gbps, they can also be used at various data capacities such as 100 Gbps and 200 Gbps without replacing parts, so they have the advantage of being applicable to existing optical communication networks.”