Coherent Optics Converging To The Shannon Limit

Coherent optics is converging to the Shannon limit. The Shannon limit represents the upper bound on information transfer for an optical channel. The gap between Shannon and various modulation schemes is shrinking. Note that the higher the transfer rate, the lower the optical reach. A lower optical reach means more OEM or optical amplification and this is an outcome carriers wish to avoid. These sort of tradeoffs permeate optical transmission. No free lunch. 

Graph Depicting Modulation Schemes Converging To The Shannon Limit

Comments

Post a Comment

Popular posts from this blog

How To Calculate An IRU Price For a 100G Wavelength

The IRU price should reflect your forecast of future lease revenes. If the current MRC is high and prices have been stable and are expected to remain so, then the opportunity cost of selling an IRU is high. You are sacrificing a lot of lease revenue if you sell that capacity. In this case the upfront IRU price should equal the three year MRC multipled by 4 to 6 years. So if the three year Faster cable MRC is $17K, then 48x to 72x times that number is fair value. So 48*$17K=$816K. Plus a standard 4% annual fee to cover the wavelength's share of maintenance and operations.. So strong markets and tight capacity mean that leasing is more attractive than IRUs to the supplier. Vice versa, the buyers will be desperate to lower their long term costs via an IRU. In my example, $816K divided by 15 years equates to $4500 per month excluding O&M. Bad for the seller. Good for the buyer. That's why so many of you are looking for IRU capacity to resell to your clients, but finding few se
Read more

Burying Fibre Optic Subsea Cables In Shallow Waters: The How And Why

Image
It is standard practice to bury subsea cables in shallow waters. This generally means the ocean or sea lying above the continental shelf. The shelf is really just that part of the continent that is submerged under water during the warm periods between the earth's recurring ice ages. During interglacial periods like now the shelves remain submerged and during each ice age the shelves become dry land as the sea levels fall due to less precipitation. Precipitation declines as the earth becomes colder and water is locked up in snow, ice, and glaciers on dry land. Indeed, during the last ice age the oceans were about 130 meters lower than today's levels and the continental shelves were dry land. In general, the continental shelves range from 100 to 200 meters below the water surface. At the continental shelf's edge the depths plunge down a steep slope to the bottom of the ocean. The purpose of burying is to protect a fibre optic cable from its most ferocious predators and enemi
Read more

Buyer Pricing Guidance: The Atlantic

Image
The Atlantic at the 100G level ranges from $4K to $6K MRC. The cables deployed at or around the time of the New Millenium vary from $3,800 to $5K. Generally, new cables like Marea and Dunant command a premium because they directly connect Ashburn Equinix to Continental Euroipe with both Ashburn Equinix and at least two Paris Equinix facilities onünet. Both bypass Ireland and the British isles. So expect to pay in the $5K to $6K range on 2 or 3 year terms. And yes, you should pay the premium because Marea, Dunant, Anjana, and Nuveem all dramatically improve resiliency. The NYC/London cooridor is congested with most UK landings in Cornwall at Bude. Furthermore, UK surveillance of undersea cables is well known.  Any saavy buyer should be riding both NYC/London cables and also cables like Dunant and Marea that directly link Ashburn Equinix to the European continent. This physical diversity is not a luxury; it's essential. A special mention goes to EXA Express for NYC/London which is a
Read more