The world’s first successful transmission of 1 petabit per second in a multicore fiber with a standard sheath diameter

Researchers at the National Institute of Information and Communication Technologies (NICT) Network Research Institute are the first in the world to report a demonstration of more than 1 petabit per second in a multicore fiber (MCF) with a standard diameter of 0.125 mm.

Researchers led by Benjamin J. Puttnam have designed a transmission system that supports recording optical bandwidth in excess of 20 THz using wave multiplexing (WDM) technology. It includes commercially accepted fiber optic transmission windows known as C and L-bands and extends the transmission bandwidth to include the recently explored S-band. Two types of doped fiber amplifiers, along with Raman amplification with pumps added to the new multi-core pump combiner, have enabled the transmission of 801 wavelength channels across the 20 THz optical band.

A large number of wavelength channels were transmitted in each core of the 4-core MCF, which is notable for having the same sheath diameter as a standard optical fiber. Such fibers are compatible with current cabling technologies and do not require the complex signal processing required to decode signals in multimode fibers, which means that conventional transceiver hardware can be used. 4-core MCFs are considered the most likely of the new advanced optical fibers for early commercial adoption. This demonstration demonstrates their potential to transmit information and is an important step towards the implementation of backbone communication systems that support the development of Beyond 5G information services.

The results of this experiment were accepted as a post-closing presentation at the International Conference on Laser and Electro-Optics (CLEO) 2022 and presented on Thursday, May 19, 2022.

The demand for increased data transmission capacity has inspired both research into new spectral transmission windows and advanced optical fibers using spatial domain parallelization. In recent years, advanced fibers with the same sheath diameter as standard single-mode optical fibers have been designed, but able to support multiple propagation paths. These fibers can multiply transmission capacity, but are still compatible with existing manufacturing processes and have proven to be a likely candidate for short-term commercial adoption of these transformational communication technologies.

NICT has achieved various world records in the design of various transmission systems using the new optical fibers and in December 2020 succeeded in the first transmission demonstration of 1 petabit per second in a standard diameter fiber using a 15-mode optical fiber. However, such fibers require complex MIMO (Multiple-input-multiple-output) digital signal processing to decode interleaved signals, and practical deployment is expected to require extensive development of dedicated integrated circuits.

NICT designed the transmission system using a 4-core MCF with a standard casing diameter of 0.125 mm, WDM technology and mixed optical amplification systems. The system enabled the transmission of 1.02 petabits per second over a distance of 51.7 km. Previously, 610 terabits per second was achieved in a similar fiber, but only using part of the S-band.

In this experiment, by extending the bandwidth of Raman amplification to the entire S-band and using matched thulium-doped fiber amplifiers (TDFA) for S-band and extended L-band erbium-doped fiber amplifiers (EDFA), the researchers were able to use a record 20 THz optical spectrum with a total of 801 x 25 GHz distributed wavelengths, each with double polarization-256 QAM modulation for high spectral density in all wavelength bands.

The standard-diameter 4-core MCF is attractive for the early adoption of new space multiplexing (SDM) fibers in high-capacity and long-distance links because it is compatible with conventional cable infrastructure and is expected to have mechanical reliability comparable to standard ones. single-mode fibers. In addition to 5G, an explosive increase in data traffic from new information and communication services is expected, so it is crucial to show how new fibers can meet this demand. We hope that this result will help in the implementation of new communication systems capable of supporting new bandwidth-intensive services.

NICT will continue to support research and development of advanced optical fibers for near and long-term applications, while striving to continuously improve optical communication systems for the benefit of society. We will further develop broadband transmission systems and explore technologies to further increase the transmission capacity of low-core, multi-core and other new fibers. NICT will also seek to expand the transmission range of ultra-high capacity systems.

A paper containing these results was presented at the International Conference on Laser and Electro-Optics (CLEO) 2022.

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Provided by the National Institute of Information and Communication Technologies (NICT)