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Submarine Cable Map

submarinecablemap.com

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Re: Submarine Cable Map

#41

Post by samstave »

jleader wrote: post #39
samstave wrote: post #30

I want to know what optics they are using. On segments that are 7,000 miles long - are there active optic splice boxes along the length of the cable? Or are they using lasers that actually push 7K miles?

The diagram of the Polar King cable-laying ship that gk1 posted here shows a "repeater stack" near the holds full of cable. I assume the repeaters are spliced into the cable as it's being laid. http://en.wikipedia.org/wiki/Submarine_communications_cable#... describes the repeaters in a modern submarine telephone cable, and says: "The optic fiber used in undersea cables is chosen for its exceptional clarity, permittin…

That means that in a ~7K mile cable run, they have ~110 repeater stacks. Wow, that's a lot.

I am still interested in who's optics/equipment are in those repeater stacks and how they power them.

Re: Submarine Cable Map

#42

Post by bdb »

samstave wrote: post #30

I want to know what optics they are using. On segments that are 7,000 miles long - are there active optic splice boxes along the length of the cable? Or are they using lasers that actually push 7K miles?

Submarine cable systems often employ repeaters (hardened EDFAs). I remember one vendor bragging that not one of their units had EVER failed in service.

If you want to see what they look like: http://www.nec.com/en/global/prod/nw/submarine/product/ns-se...

Re: Submarine Cable Map

#43

Post by bicknergseng »

gk1 wrote: post #12

For anyone curious as to how they're actually laid, here's a simple diagram of a typical cable layer ship (CS): http://www.murmanchanin.ru/shipnoise/polar_king/polar_king.j... And a simplified diagram of how it operates: http://www.fiberinc.net/images/sea.jpg

What's amazing to me is that these cables were laid without a lot of fanfare. Seems to me if I were Level1 or whoever else and had just completed a 10,000 km cable across an ocean, I'd make sure the press release saw some circulation.

The same thing with satellite launches. I feel like these are fairly major feats of engineering that go basically unheard of unless you're in certain small circles.

Re: Submarine Cable Map

#44

Post by bdb »

bdb wrote: post #42
samstave wrote: post #30

I want to know what optics they are using. On segments that are 7,000 miles long - are there active optic splice boxes along the length of the cable? Or are they using lasers that actually push 7K miles?

Submarine cable systems often employ repeaters (hardened EDFAs). I remember one vendor bragging that not one of their units had EVER failed in service. If you want to see what they look like: http://www.nec.com/en/global/prod/nw/submarine/product/ns-se...

Actually, there are much better photos in this PDF: http://www.nec.com/en/global/prod/nw/submarine/pdf/submarine...

Look at the last page for a photo of one of the amps with people in the frame for scale.

Re: Submarine Cable Map

#45

Post by verelo »

mikeocool wrote: post #6
verelo wrote: post #4

I've always wondered where they are. Can you imagine just how long it took to wrap a wire around the whole world a few times over? The thing that shocks me is how recently these were added. I was checking out the cables in Australia, expecting them to have been added in the 60's or something....however most are around the year 2000-2010.

Yeah, I was thinking the same thing, almost all the transatlantic cables seemed to have been laid in the 2000s as well. I ran across this: http://en.wikipedia.org/wiki/Transatlantic_telecommunication... Seems like each cable generally only has a life of 10-20 years.

10-20 years...gez there must be a lot of cables down there then. I am sure that some kind of salvage operation would be worthwhile if well thought out...it wouldnt be easy to do it at a profit but i could sure go for a few thousand kg of copper!

Re: Submarine Cable Map

#46

Post by tomkinstinch »

samstave wrote: post #41
jleader wrote: post #39

Earlier quoted context omitted.

The diagram of the Polar King cable-laying ship that gk1 posted here shows a "repeater stack" near the holds full of cable. I assume the repeaters are spliced into the cable as it's being laid. http://en.wikipedia.org/wiki/Submarine_communications_cable#... describes the repeaters in a modern submarine telephone cable, and says: "The optic fiber used in undersea cables is chosen for its exceptional clarity, permittin…

That means that in a ~7K mile cable run, they have ~110 repeater stacks. Wow, that's a lot. I am still interested in who's optics/equipment are in those repeater stacks and how they power them.

They are "powered" by lasers themselves. No electronics involved; excess energy from a pumping laser boosts the intensity of the data laser, using sections of special doped fiber.

http://en.m.wikipedia.org/wiki/Optical_amplifier#Doped_fiber...

Re: Submarine Cable Map

#47

Post by bdb »

kijin wrote: post #11
mikeocool wrote: post #6

Earlier quoted context omitted.

Yeah, I was thinking the same thing, almost all the transatlantic cables seemed to have been laid in the 2000s as well. I ran across this: http://en.wikipedia.org/wiki/Transatlantic_telecommunication... Seems like each cable generally only has a life of 10-20 years.

Hmm, then what happens to outdated cables? Do we pull them up, or do we just turn off a switch at the shore and leave the rest in the ocean? Do the cables contain any substance that might pollute the seabed as the casing degrades away?

In certain cases, e.g., the cables AT&T laid between Hawaii and the mainland US, they were decommissioned from active service and then used to power a network of undersea sensors used for research by the University of Hawaii:

http://aco-ssds.soest.hawaii.edu/

Re: Submarine Cable Map

#48

Post by miahi »

falcolas wrote: post #27

I found it absolutely fascinating how some continents use underwater cables to connect different locations within a continent (Africa, notably, seems virtually surrounded), while others seem to only have significant outbound connections (North America, Australia). I can only guess it has more to do with whether you cross national boundaries (since even the US has underwater cables bridging the mainland to Alaska) tha…

If you take a look at an Internet penetration map[1] you will see that most of the cables around Africa have only a few big "customers": Morocco, Egypt, Nigeria and South Africa. If you compare that map with a GDP map you will also see why: poor countries, without terrestrial infrastructure and some with unstable political situations.

[1] http://en.wikipedia.org/wiki/File:Internet_Penetration.png

Re: Submarine Cable Map

#49

Post by onemoreact »

bicknergseng wrote: post #43
gk1 wrote: post #12

For anyone curious as to how they're actually laid, here's a simple diagram of a typical cable layer ship (CS): http://www.murmanchanin.ru/shipnoise/polar_king/polar_king.j... And a simplified diagram of how it operates: http://www.fiberinc.net/images/sea.jpg

What's amazing to me is that these cables were laid without a lot of fanfare. Seems to me if I were Level1 or whoever else and had just completed a 10,000 km cable across an ocean, I'd make sure the press release saw some circulation. The same thing with satellite launches. I feel like these are fairly major feats of engineering that go basically unheard of unless you're in certain small circles.

People laid undersea cables for telegraphs and back then it was a big deal. However, it's been 154 years and people stopped being impressed a while ago. http://en.wikipedia.org/wiki/Transatlantic_telegraph_cable

Re: Submarine Cable Map

#50

Post by dotBen »

bdb wrote: post #42
samstave wrote: post #30

I want to know what optics they are using. On segments that are 7,000 miles long - are there active optic splice boxes along the length of the cable? Or are they using lasers that actually push 7K miles?

Submarine cable systems often employ repeaters (hardened EDFAs). I remember one vendor bragging that not one of their units had EVER failed in service. If you want to see what they look like: http://www.nec.com/en/global/prod/nw/submarine/product/ns-se...

How do they power the repeaters? I thought the cable itself was just fiber optic, thus no electricity transmission
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