Talk:Polarization-maintaining optical fiber

Errors?
Many of the statements are simply wrong.

Article needs a quality check. —Preceding unsigned comment added by 88.217.227.129 (talk • contribs) 10:36, 16 July 2008


 * Which statements do you think are wrong? I don't see any problems.--Srleffler (talk) 05:45, 17 July 2008 (UTC)

Just came to this talk page because I stepped over the sentence in the article that PM fiber was "important in modern telecommunication". AFAIK, nearly every piece of modern telecommunication is designed (and has the explicit design goal) to be polarization *independent*. Telecom commonly uses "normal" (non-PM) single-mode fiber and all components on the way are designed to be polarization independent (with exception of EO modulators mounted directly after laser diodes). PM fiber is not used in telecom because over distances in the km range, the two polarizations suffer considerable cross-coupling (giving rise to interference). This is even worse because the two polarizations travel at different speeds ("slow axis", "fast axis"). The only "mass use" of PM fiber I am aware of is fiber gyroscopes applying Sagnac interferometers (as used in military missiles and similar). Due to the comparatively low production volume, PM fiber is more than 100 times more expensive than standard telecom SMF (e.g. OFS AllWave). —Preceding unsigned comment added by 141.84.219.146 (talk) 16:35, 29 May 2009 (UTC)


 * I guess it comes down to what the definition of "important" is. AFAIK source lasers for long-distance telecomm are always pigtailed with PM fiber, so they can be used with modulators. Are sources and modulators not important in modern telecommunication? The article probably should be clearer that pm fiber is not used for the actual outside plant lines.


 * I may be biased on this issue: I have worked with PM fiber far more than standard singlemode fiber.--Srleffler (talk) 03:12, 30 May 2009 (UTC)


 * Your statement about "source lasers for long-distance telecom" is exactly what I meant above with "expection of EO modulators mounted directly after laser diodes". From the point of use, standard single-mode "telecom" fiber is definitely the most important fiber in telecom. If you talk about "standard telecom fiber" you always mean non-PM SMF. Short-distance fiber network patch"cables" are non-PM just as transatlantic lines (commonly combined with DCF and EDFAs). I like the article in the current version. —Preceding unsigned comment added by 93.135.62.39 (talk) 23:06, 5 June 2009 (UTC)

Diagram
A diagram similar to figure 1 in the LFW article would be good, except that the "bow tie" fiber should also have a core at its center, similar to the Panda fiber. Other example images here and here.--Srleffler (talk) 05:45, 17 July 2008 (UTC)
 * I've created one: Image:PM optical fibres.svg. Is that what you wanted? Bart133 t c @ How's my driving? 22:25, 21 August 2008 (UTC)
 * Thanks, it's perfect!--Srleffler (talk) 02:26, 22 August 2008 (UTC)

Elliptical polarization
If linearly polarized light sent into a PM fiber is not aligned with its principal stress direction, it is NOT elliptically polarized as indicated in the article. In this case, the linearly polarized light has a component in each of the two principal stress directions (call them X and Y directions). For elliptically polarized light, both components have the same wavelength, but are out of phase by any angle except 0 & 180 degrees (linearly polarized) and 90 & 270 degrees (circularly polarized). However, in PM fiber, the index of refraction "seen" by light polarized in the X direction is different than that "seen" by light polarized in the Y direction. The result is a different wavelength for each principal stress direction which does not occur in elliptically polarized light. — Preceding unsigned comment added by MEmmons333 (talk • contribs) 02:15, 3 February 2011 (UTC)
 * The article says that the output (i.e. the light leaving the other end of the fiber) will generally be elliptically polarized. The wavelength difference you mention occurs only within the fiber. When the X and Y components leave the fiber, their wavelengths become equal again.--Srleffler (talk) 05:44, 3 February 2011 (UTC)

Article now just free advertisement to a commercial website.
The article titled "PANDA-style fibers move beyond telecom." just links to a companies webpage where they sell any number of commercial fiber optic products. I cannot find the original article through any of the links listed on this page or on this website. The link should be deleted or updated. — Preceding unsigned comment added by 71.42.11.147 (talk) 15:07, 5 December 2012 (UTC)
 * Thanks. I have fixed the problem. If you are interested in the article, you should be able to find it in print in any University physics library. Laser Focus World August, 2004 issue.--Srleffler (talk) 04:33, 6 December 2012 (UTC)

Broken link
The first reference pdf link is not working. I googled the pdf file name and go this: http://www.fujikura.co.jp/eng/resource/pdf/16pnb04.pdf — Preceding unsigned comment added by 67.221.224.4 (talk) 21:02, 1 November 2016 (UTC)