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Technology Stocks : The *NEW* Frank Coluccio Technology Forum -- Ignore unavailable to you. Want to Upgrade?

To: elmatador who wrote (31902)	10/31/2009 4:23:45 PM
From: Frank A. Coluccio	Read Replies (7) \| Respond to of 46821

Pray tell, how did you arrive at 2017? I ask because the more forward-looking European carriers (namely, FT and DT, and on this side of the Atlantic VZ, as well), at least, have already stated aggressive objectives to consolidate their services in "jumbo hubs" closer to the core by backhauling their end user traffic via fiber, thus eliminating the need to house equipment closer to the customer. This is what enables them to decommission the majority of their central offices as they are used today, although I'm not aware of any precise time lines in any of the instances I've cited above. It also occurs to me that, by the time copper loops are eliminated as a last mile solution, fiber would still in most cases traverse the same geographical points on the map where those COs now stand. That's just how cabling infrastructure topology evolves over time and establishes permanence. Hopefully, by that time most end users will be receiving symmetrical services and some of those COs might be converted to local collocation sites for hosting end-user backup and disaster recovery service hubs, content caching and repositories, and, in general, Cloud/Web hosting sites for residential, so-ho and SMBs. In other words, I'm suggesting that Cos could be transformed --not into parking lots, but into collocation centers for end users whose requirements don't quite scale high enough to cost justify leasing cages in larger carrier hotels and collocation centers. ------

To: elmatador who wrote (31902)	11/25/2009 6:34:13 PM
From: axial	Respond to of 46821

Amplifying noise for cheap fiber optics Getting good broadband and voice speeds requires good infrastructure. Fiber to the home is arguably the best way to go, but that's prohibitively expensive in the developing world. A new advance may change that. -snip- "When left to their own devices, diode lasers will emit over a fairly broad range of wavelengths. Manufacturers of telecom diodes build structures into the diodes that provide a huge amount of feedback for a predefined wavelength and very little for others. This results in a laser with a very precise wavelength and a very high price tag (relatively speaking). The odd thing is that in long-haul networks, this isn't good enough, because the signal must be periodically amplified. The amplifiers don't just amplify the signal, they amplify the noise as well. Left alone, light in between—and in—each channel builds up and eventually you end up with a mess. To reduce this, filters are put before and after each amplification stage, reducing the amount of light sitting in between channels and slowing the build-up of noise. The important thing is that these filters are nearly as precisely defined as the original laser diodes, but are much much cheaper. A group of researchers from Taiwan took note of this and thought that filters combined with an amplified spontaneous emission source might replace several expensive laser diodes. Here's how an amplified spontaneous emission source works. Imagine you have a laser crystal which you have just excited, so there is a whole bunch of ions just sitting there waiting to emit. One of them does emit, and, as that photon passes through the crystal, it stimulates other photons to emit. This is the first part of what makes a laser: amplification. But, in a laser you also have feedback—mirrors reflect the amplified spontaneously emitted light back to stimulate more emission. Without the mirrors, the crystal just glows weakly and everyone goes off to buy a fluorescent light. If we replace the crystal with an optical fiber, a certain fraction of the spontaneously emitted light is guided by the fiber. As this light travels along the fiber, it becomes amplified by stimulating other excited ions to emit. In the end, you can end up with hundreds of watts of power being emitted from an optical fiber, but it is not laser light. (That's because measuring the properties of the light in one instant of time tells you nothing about what the light will be like at some later point in time—there is no feedback to allow light emitted earlier to stimulate the emission of light later.) On the end of the active fiber, the researchers placed a filter. They ended up with a comb of wavelengths that happen to correspond to exactly what is expected on telecom networks. One problem: laser diodes occupy a tiny fraction of the filter bandwidth and more of the bandwidth is occupied by adding information to the signal. In this case, however, the source completely fills the bandwidth. Even so, the researchers demonstrated links operating at 1.25Gbps. However, because of the nature of the source, only every second channel can be used, so in terms of link capacity, this sits at half of that of a traditional fiber network. But balanced against what we gain—the same source can be used for every village, and higher-capacity networks cost nearly the same as low-capacity networks—I think they are onto a winner, even in the developed world. Compared to the microwave solutions I worked on, and traditional fiber networks, this is much cheaper—depending on the terrain. But for a 60-mile ring network over relatively easy ground, it would work out to be cheaper still. This is perfect for those situations where power is available, but the phone lines absolutely stink, like parts of rural India, southeast Asia, and Africa." arstechnica.com Jim