June 1, 2022
… while Airguide Photonics’ hollow core fiber development achieves “record low” propagation losses.
Researchers at Japan’s National Institute of Information and Communication Technology (NICT) Network Research Institute have reported the world’s first demonstration of more than 1 petabit per second in a standard-diameter multicore fiber of 0.125 mm.
The researchers, led by Benjamin J. Puttnam, built a transmission system that supports a record optical bandwidth exceeding 20 THz by exploiting wavelength division multiplexing (WDM) technology. It incorporates commercially adopted fiber optic transmission windows known as C and L bands and expands the transmission bandwidth to include the recently scanned S-band.
The results of this experiment were accepted as a presentation of the paper after the deadline at the International Conference on Laser and Electrooptics (CLEO) 2022, earlier this month.
Two types of doped fiber amplifiers along with Raman amplification with pumps added in a new multi-core pump combiner, allowed the transmission of 801 wavelength channels over the 20 THz optical bandwidth.
The large number of wavelength channels were transmitted to each core of a four-core MCF that stands out for having the same coating diameter as a standard fiber optic. These fibers are compatible with current cabling technologies and do not require the complex signal processing required to decrypt signals into multimode fibers, which means that conventional transceiver hardware can be used.
Four-core MCFs are believed to be the most likely new advanced fiber optics for early commercial adoption. This demonstration shows its potential for information transport and is an important step towards the realization of core communication systems that support the evolution of Beyond 5G information services.
Fund
The demand for improved data transmission capacity has inspired both research into new spectral transmission windows and advanced optical fibers that exploit parallelization in the space domain. In recent years, advanced fibers with the same coating diameter as standard single-mode optical fibers but capable of supporting multiple propagation paths have been proposed.
NICT has achieved several world records by building various transmission systems using new fiber optics and in December 2020 was successful in the first demonstration of 1 petabit per second transmission in a standard diameter fiber using a 15 fiber optic modes.
However, these fibers require complex MIMO (Multiple-input-multiple-output) digital signal processing to decipher the signals that are shuffled during transmission, and practical deployment is expected to require large-scale development of dedicated integrated circuits. .
NICT built the latest transmission system using 4-core MCF with a standard coating diameter of 0.125 mm, WDM technology and mixed optical amplification systems. The system allowed the transmission of 1.02 petabits per second in 51.7 km. Previously, 610 terabits per second was achieved on a similar fiber but only using part of the S band.
The hollow fibers show a low “record” loss.
Nature Photonics has published research from Southampton’s Airguide Photonics program on the development of hollow core fibers with record low propagation losses and exceptional power handling properties.
The research focuses on the transmission of kilowatt power laser beams at fiber lengths on a kilometer scale, while preserving a virtually ideal single-mode beam quality. This transmission is impossible on conventional optical fibers, as the high intensity of the laser interacts with the glass and quickly compromises the integrity of the beam, which means that single-mode kilowatt power levels can normally only be transmitted. in a few tens of meters in conventional fibers.
Dr. Hans Christian Mulvad of Southampton, who led the high-power transmission experiments, commented: “The enabling technology behind our advancement is the development of hollow core fibers with record low propagation losses. laser propagates inside a hollow core, instead of a solid glass core as in a conventional fiber, harmful nonlinear interactions with glass are virtually eliminated.This allows to transmit very high power levels without any harmful effect on the quality of the beam.
“In addition, low loss is essential for energy-efficient transmission, allowing most of the power from the laser source to be delivered to the fiber output even after a mile,” he said.
“Recent advances have shown that propagation loss has been reduced to record levels, comparable to fibers set at near-infrared telecommunication wavelengths and even lower in the visible range of the spectrum. .It’s one of those record-breaking NANFs, operating in the near infrared, that is used in this work. “
“This fiber and arrangement allowed the research team to demonstrate the transmission of a single-kilowatt laser beam over a kilometer, with a total power loss of only 20 percent. Mulvad added:” We also performed detailed numerical simulations that show that fiber can withstand even higher power levels and longer transmission lengths, underscoring the NANF’s superior performance over conventional fibers for single-mode power delivery. “