By: Rhonda Moniz
Ocean News & Technology recently spoke with Mark Enright, vice president, customer solutions at TE SubCom about this new development in undersea fiber optic technology.
ON&T: What is C&L technology and how is this repeater different from its predecessors?
Mr. Enright: C+L technology refers to the signal amplification technology used in the undersea repeaters.
Standard repeaters support the “conventional” transmission band, or C-band, near the minimum attenuation wavelength of optical transmission fiber. The C-band is determined by the strongest amplification Band of Erbium-doped fiber, which is used to provide the optical amplification in the repeaters. The C-band is limited to about 4.5 THz of bandwidth for optical amplification.
TE Connectivity SubCom Repeater. Photo credit: TE SubCom.
However, Erbium-doped fiber can also provide amplification on the long wavelength side of the C-band, even though amplification here is typically much weaker.With increased Erbium concentration and longer Erbium-doped fiber length in the amplifier design, similar levels of amplification and performance can be achieved in the “long-wavelength” band or L-band as in the C-band. C+L technology is, therefore, an evolutionary step in repeater technology that expands on established Erbium-doped fiber technology.
ON&T: The demand for Internet bandwidth is seemingly insatiable. How will the C&L repeater help meet this demand?
Mr. Enright: Indeed, Internet bandwidth demand continues to increase exponentially, and more capacity is needed on the undersea path connecting continents. C+L technology effectively doubles the available transmission bandwidth of the repeater, an unprecedented factor of two in supported capacity per fiber pair when compared to the same number of fiber pairs in C-band technology.
Since only half the number of fiber pairs are needed compared to a C-band repeater-based cable with the same capacity, C+L technology is much more cost competitive and opens the path to cable capacities that were previously unachievable.
ON&T: When will we begin seeing deployment?
Mr. Enright: The C+L repeater has been in development at TE SubCom for the last two years and has just recently entered the production stage. Manufacturing for the wet plant of a contracted and funded large transoceanic system is underway and the ready-for-service date is scheduled for late 2018.
TE Connectivity SubCom Repeater being loaded onto a Reliance Class ship. Photo credit: TE SubCom.
ON&T: How does this repeater fit in with the equipment and services offered by TE SubCom?
Mr. Enright: The new C+L repeater fits seamlessly into the equipment and services offered by TE SubCom. There is no physical difference on the outside of the repeater body compared to a standard C-band repeater, and the new C+L repeater fits all the existing handling and installation procedures.Optical Add/Drop Multiplexing (OADM) technology for the L-band is in development alongside the C+L repeater enabling complex undersea OADM network architectures and applications while leveraging the benefits of C+L technology.
ON&T: What do you see for the future of the submarine cable market?
Mr. Enright: The future of the submarine cable market is vibrant and bright! Bandwidth demand between data centers will continue to be driven upward by virtual reality, the Internet of things and machine-to-machine traffic.Increased requirements for cable route diversity will provide better network resilience against faults and attacks.In response, we will continue to innovate with new technology, better engineering, and creative solutions.