FEATURE
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KEY QUESTIONS FOR YOUR SUBOPTIC VISIT BY GEOFF BENNETT
T
he Suboptic conference and tradeshow comes but once every three years, and 2025 is our lucky year because, while some other conferences have succumbed to the “pay to play” approach, where sponsors simply pay to present uninspiring product pitches, the presentations at Suboptic actually still have interesting content. You also have access to some of the best minds in the subsea industry for one to one discussions. With this in mind, I’d like to suggest three key questions you could ask the experts if you’re planning to attend the event. There will be one question for transponder vendors and two questions for wet plant vendors – but all three questions relate to scaling challenges for present and future submarine cable systems.
THREE KEY QUESTIONS QUESTION FOR TRANSPONDER VENDORS
Question 1: What are your future plans for increasing capacity on submarine transponders? Is this still a focus, or are you looking at other scaling factors? Background: Coherent transponders have been incredibly successful at delivering enhanced spectral efficiency over submarine cables in the past 15 years. The latest transponders are within 2 dB of the theoretical spectral efficiency limit (aka Shannon Limit) for uncompensated fiber pairs, and additional SE gains are getting extremely difficult to
80 SUBMARINE TELECOMS FORUM MAGAZINE
achieve, while delivering comparatively little additional capacity. Moreover, the financial cost, size of transponders and electrical power consumption that would be required may not be the desired outcome for fiber pair operators. So, if spectral efficiency is no longer the focus, what are transponder vendors planning?
QUESTIONS FOR WET PLANT VENDORS
Question 2: What is your next technology step to deliver a transatlantic reach, 1 Petabit/s submarine cable? Background: The highest capacity transatlantic cable today is Anjana, which will be able to support over 500 Tb/s total capacity across 24 fiber pairs. Anjana uses standard 17 mm cable which would normally be limited to 16 fiber pairs, assuming conventional 250 micron fibers are used. Trying to pack more 250 micron fibers than this into the limited dimensions of the cable compartment would introduce microbending losses. But Anjana uses 200 micron fiber – where the outer cladding thickness has been reduced in order to support more fiber pairs in the same diameter cable compartment. 200 micron fibers are common in terrestrial networks, but Anjana is the first transatlantic cable to use them. For most 17 mm cable designs, 24 x 200 micron fiber pairs is the maximum that can be supported without risking additional microbending losses. So what are the Wet Plant vendors planning for the next capacity leap – ideally to achieve a full 1 Petabit cable?