Mega Bandwidth Acheived

PDG writes "The german engineering firm Siemans has produced the rate 1.2 tbs (YES, tera bits per second) over a SINGLE strand of fiber, thus proving the limitless power of fiber. " One step closer to the ultimate goal for humanity: infinite bandwidth. Or maybe thats just my ultimate goal. Nevermind.

Comments

Limits of Erbium

[Anonymous Coward]

Correct! I did some research on these Erbium amplifiers during my undergrad work, and here's the skinny: It turns out that the most efficient wavelength in fiber optics can be reproduced by a certain energy level delta in erbium (since its higher atomic number provides many deltas to work with). What they do is excite the erbium atomes with a laser. The fiber is looped along the doped section of fiber--bent fiber=loss of signal. As the signal is lost, it collides, in phase, with all the excited Erbium atons, which all release this effifcent wavelength. This method provides an amplification on the order of 40dB, which is immense. It also vastly cleans up any bandwidth spreading that would be present.
Interestingly enough, it sounds like this multiplexing method, while drastically increasing bandwidth, may make this elegant method unusable. Different wavelengths would need different energy levels, all of which probably could not be produced by erbium. I would be interested in seeing how they get around this, if they can. IF they actually have to go to an electric amp, they will probably loose most of the bandwidth they are trying to create! I suppose they could dope the fiber with multiple atom types to simultanously amplify all bandwiths. However, the entire fiber would need to be amplified at a rate consistant with the most inefficient wavelength in the signal, making the entire process more expensive.