Talk:Wavelength-division multiplexing
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Added some references, but I am very new to wikipedia, and they are probably not in the correct format. If you are more experienced than I and could correct them, thanks.
[edit] CWDM - 8 or 16?
Part of the article says that CWDM is 8 wavelengths or less, and another part says it's up to 16.
There's a couple of iterations of the standard. The first set has 8 wavelegnths and the second has 16, scattered over the 1310 and 1550 nm bands.
[edit] WDM Does not allow for bidirectional transfers, light does
"This allows [...] to perform bidirectional communications over one strand of fibre."
Because of the physics of light at large, light does not interfere with itself in waves passing against each other of any great angle of separation irrespective of the frequency. It may be the case that current implementations use WBM for bidirectional transfers (I do not know), but it is by no means required.
It's more a matter of practical implementation than basic physics. If you want to send light both ways over a fiber you have to be able to direct the incoming light to the detector and not to the transmitter going the other way. You can do that with a splitter which will send half of the light to the detector, and half to the transmitter. That will give you a 3 dB loss at that end. Since you would need to do this at both ends you will wind up with a 6 dB loss to make it bidirectional. Also, since half of your light still goes to the transmitter, which are very often sensitive to optical feedback, you may wind up with an unstable or noisy transmitter. If you use two wavelengths with a WDM your loss will be well under a dB, and you will pick up anywhere from 16 to >50 dB of isolation to keep interfering light away from your transmitter. (If you really wanted to use the same wavelength in both directions, wanted good isolation, lower insertion loss than a splitter, and didn't mind spending a few more bucks, you could use a circulator.)216.70.247.242 23:47, 12 February 2007 (UTC)John N.
[edit] British vs. American English -- this article uses British English
See Wikipedia:Manual of Style#National varieties of English. This article was originally written using British English and therefore we should stick to British English for consistency's sake. --A. B. 05:45, 2 November 2006 (UTC)
- Wouldn't it make more sense to stick with the spelling of the optical fiber page, the American one? —The preceding unsigned comment was added by 130.126.76.122 (talk • contribs) 15:33, 14 November 2006 (UTC)
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- There's some logic to that, however, you would be amazed at some of the bizarre, silly fights that have erupted over this topic. See (or skim) Talk:Under the Umbrella Tree#Canadian vs. American spelling and Talk:Under the Umbrella Tree#RfC for an example; as for my own true feelings, you can read my own comments at the end of the RfC section. (You might also enjoy some of the uniquely Canadian/American links I posted).
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- I made my 2 November comment above after a new, fiber-savvy editor, unfamiliar with the rules, conscientiously went through and fixed all the "misspellings" (which I then reverted). --A. B. 22:11, 14 November 2006 (UTC)
