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Technology Stocks : JDS Uniphase (JDSU) -- Ignore unavailable to you. Want to Upgrade?

To: quidditch who wrote (773)	8/11/1999 6:11:00 PM
From: Bulldozer	Respond to of 24042

steven, FBGs have many uses throughout a WDM system. They can be used at the source for wavelength stabilization (in competition with wavelocker products now), at ADMs to add/drop selected lambdas, at WDMs to demux wavelengths or in our current case, in EDFAs. FBGs and related LPGs (long-period fiber gratings), are used for gain flattening and dispersion compensation in particularly high channel count systems. Over the 1550 nm bandwidth window (1530-1560 or 70), various channels actually experience different gain (amplification) than others. In other words, the gain is not uniform and if left unattended, can produce errors and transmission difficulty in the form of differences of SNRs (signal to noise ratio) and high BERs (bit error rates). In addition, as there are usually many EDFA and amplifier stages in a system and the concatenation (accumulation or attachments to one another) results in the errors compounding. FBGs and LPGs are used directly after amplification stages to equalize the gain across the gain window. There are various ways this is accomplished which is not important at this point. There are other benefits of FBGs as well to different situations (such as what happens when you add or drop wavelengths - how do you control the amplification uniformity of all the other channels?) SDL used to (actually they still do) tout its FBG technology as a selling point against JDSU at the higher channel count systems. The reason SDL had this lead was due to the fact they had an inferior product originally which was not as stable as Uniphase's 980. As the market went to 10gb faster than expected (although the overwhelming number of systems out there are still 2.5), the FBG EDFA was in the right place at the right time. JDSU now offers this feature. Bulldozer