RocketMan, a good submarine f-o FAQ page can be found at the link I've provided below. Instead of free-forming an answer to your question, I'll just post from the link, after my sign-off below.
The repeaters, incidentally, take the shape of an in-line torpedo, very slim in proportions, both for pulling and aqua-dynamic reasons.
One of the perils of repeater design is the potential for reaching operational limits in the deep sea component, i.e., reaching a premature bandwidth ceiling, while advancements are being implemented into the terminal equipment on shore to boost throughput.
The weakest link, or in this case, the most restricting network element when it comes to throughput, can easily be mid-ocean repeaters that would need to be pulled up and retrofitted at some point.
This may be one of the advantages, conceivably, aside from the protection switching it affords for fail-safe operations through self-healing techniques, of putting in a dual-segmented ring architecture, since future upgrades can be performed on one arc of the ring at a time. Although, I've not seen this written anywhere, it's conceivable to me that with cooperative recovery measures in the way of mutual assistance programs between submarine consortia, i.e., programs put in place with other submarine consortia, this is a doable arrangement.
If this subject interests you you may want to search using the following search terms: submarine cable fiber optic repeaters spacing
You may also want to visit the FAQ site below, which may be slightly dated w.r.t present day throughput speeds and related parameters, [then again, the story of throughput potential is being written as we type] but it contains most of the rudimentary information you'd be looking for, most of which does not change in principle, only in proportions.
Best Regards, Frank Coluccio
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teleport.com
Question: Do undersea cables make do without undersea repeaters to boost the signals? If so, how?
Answer: Most existing cable systems, both optical and copper, utilize electronic repeaters. However virtually all new systems planned are doing without repeaters by using optical amplifiers which exploit the physical properties of doped-glass fiber (erbium) to amplify the optical signal. The op-amp, which requires a pump-laser to provide signal amplification, must still be powered from the shore-end and in this way is similar to a repeater (shorter systems may require an op-map only at the shore station). The capacity on op-amp systems is much larger than for repeatered systems (1.5 Gb/s to 10 Gb/s compared to repeatered systems at less than 1 Gb/s) and can even be upgraded later in some cases (increasing the rate or switching to wavelength division multiplexing - WDM). In the future systems are planned which will use optical signals called solitons. This should greatly increase the length of non-amplified systems.
Question: What are amplifier spacing requirements?
Answer: With optical amplifier systems the amplifier spacing varies depending on the length of the system and the capacity (ie in gigabits per second). Single hop systems can reach 400km + whilst long haul systems of 40 Gigabits have a spacing of around 40km. Naturally improvements in the technology are being made all the time. |
