The global COVID-19 pandemic and the ensuing shelter-in-place orders has created an unprecedented demand for internet bandwidth taxing the full capacity of existing telecommunications networks. LLNL researchers have developed a practical solution to the challenge that leverages the existing fiber optic telecommunications infrastructure. The lab’s breakthrough enables the potential for installed optical fibers to operate in an untapped spectral region known as the E-band, a nascent capability in all existing installed optical fibers, in addition to the C- and L-bands where they currently operate -- effectively doubling a single optical fiber's information-carrying potential. The innovation is enabled by the successful development of a practical fiber-optic amplifier that generates operationally significant optical gain from 1,390 nanometers (nm) to 1,460 nm with relatively good efficiency. The LLNL E-band amplifier design is based on a novel waveguide, also developed by lab researche
Lawrence Livermore researchers are the first to successfully develop a practical fiber-optic amplifier that generates significant optical gain from 1,390 nanometers (nm) to 1,460 nm with relatively good efficiency. This discovery enables the potential for installed optical fibers to operate in an untapped spectral region known as the E-band, in addition to the C- and L-bands where they currently operate -- effectively doubling a single optical fiber's information-carrying potential.
LLNL’s new amplifier design is based on a novel Neodymium-doped microstructured optical fiber that is tailored to preferentially enhance optical signal gain in the E-band while effectively suppressing competing gain in other spectral bands. The new amplifier design is built around the same architecture as current conventional erbium-doped fiber amplifiers. The new amplifier can easily be converted to a fiber laser operating over the same wavelength range.
IP status: US patent 10,348,050 "Nd3+ fiber laser and amplifier" (LLNL internal case # IL-13120).
US patent 10,033,148 "Waveguide design for line selection in fiber lasers and amplifiers" (LLNL internal case # IL-13058).
US patent pending “Wavelength selective filtering with non-radial array of microstructure elements“ (LLNL internal case # IL-13512).
Applications and Industries
The primary utility of the Neodymium-doped fiber amplifier is in regeneration of telecommunication signals in the wavelength range from 1,390 – 1,460 nm. The Neodymium amplifier can also be converted to a laser operating over the same spectral range.
The LLNL Neodymium-doped fiber amplifier has the same architecture as conventional fiber amplifiers already widely deployed. Instead of having to lay more cable, these new amplifiers could be installed in the same buildings as the current amplifiers, resulting in twice as much bandwidth on current cables.
Installation of new cable is expensive; a service provider must not only purchase new cables, but also undergo the large expense of digging trenches to install the new cable.
LLNL's new amplifiers would potentially allow telecom companies to more advantageously leverage their installed base of equipment, requiring less capital investment than new cable -- resulting in expanded bandwidth and lower costs for their customer base.
Technical and economic advantages of LLNL's Neodymium-doped Fiber Amplifier technology include:
- opening up a new telecom transmission band that is compatible with existing infrastructure
- increasing the data transmission capacity of optical fiber networks without having to install new fiber
- operating in a spectral band that is sufficiently separated from existing C- and L-bands enabling simple, inexpensive provisioning at substations for independent amplification and routing
- no other practical fiber amplifier solutions exist in this spectral range which is still in the low loss window for most long haul optical fibers
- operating in a spectral band sufficiently far from the current C- and L-bands to minimize non-linear interactions
- the Neodymium-doped fiber amplifier is very similar in “look and feel” to conventional Erbium-doped fiber amplifier for easy adoption by the telecom industry