Talk:Wavelength-division multiplexing

message: I don't understand why Infinera is redirected to Wavelength-division multiplexing. FYI Infinera is one DWDM equipement manufacturer, growing pretty fast over the last few years. 13:02, 23 April 2009 (UTC)
replies: text: I don't understand this either.  how can it be fixed? Opticalgirl (talk) 15:50, 4 September 2009 (UTC)

text: OK I have worked how to remove the redirect.  Created a basic page, but it needs more info. Opticalgirl (talk) 16:45, 4 September 2009 (UTC)
thread_title:  Infinera 

message: 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.
In the description of DWDM there is a small discrepancy in the lower frequency limit of C-band - 1525nm & 1530nm. There is a big mismatch in the definition of L band though - 1570nm to 1610nm in the article .... but it links to a page describing this as an atmospheric transpaency window at 3.5 microns. Clearly somebody did not read what hey linked to.  — Preceding unsigned comment added by 194.193.198.123 (talk) 04:02, 21 January 2023 (UTC)
thread_title:  CWDM - 8 or 16? 

message: "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.
--Osndok
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)
thread_title:  WDM Does not allow for bidirectional transfers, light does 

message: The page contains some factual errors. CWDM is the accepted term for applications with spacing > 100 GHz. It isn't clear whether the C refers to coarse or conventional, and the two are used interchangeably. A system with 100 GHz or denser spacing is DWDM and WDM is a blanket term that applies to both CWDM and DWDM. Madgenberyl 17:31, 18 October 2007 (UTC)
thread_title:  WDM, CWDM and DWDM 

message: It would be very interesting to know which on is better, CWDM or GEPON technology? Advantages and disadvantages...  —Preceding unsigned comment added by 85.206.21.24 (talk) 10:29, 1 April 2011 (UTC)
thread_title:  CWDM vs. GePON 

message: This article refers to etalon technology and fixed WDM only. It needs to be brought up to date and referenced to a ROADM page, if there is such a thing. Madgenberyl (talk) 06:53, 24 April 2011 (UTC)
thread_title:  Update needed 

message: I just wanna know what colors are used.  Green and red would be tacky.  — Preceding unsigned comment added by Mercster (talk • contribs) 07:08, 30 November 2019 (UTC)
thread_title:  Cut the technical crap