Talk:Fiber Bragg grating

Comment
As original author I'd agree with the merger - maybe a redirection to handle the UK spelling of 'Fibre/Fiber' is enough to fix this. --PeterMarkSmith 03:32, 28 March 2006 (UTC)

I've tried to tidy it up a bit - wikifying some links and adding a little more detail on chirped gratings. I should try to dig out some useful references as well. Need also to change the reference to apodization or at least add an explanation. I think we also need to work out how to say doping without always meaning semiconductos, though the two proceses are similar. Will revisit JohnGray 23:08, 4 November 2006 (UTC)
 * Looks good. References would be a good addition. I agree about the reference to apodization. I'm going to at least make a link there for now.--Srleffler 05:51, 5 November 2006 (UTC)

I fully agree with the merger - as I understand, the articles point to the same component, wich is more commonly known as fiber bragg grattings. I've got some material to improove this article, I just need time to organize it ;]! —The preceding unsigned comment was added by 201.37.178.140 (talk • contribs) 06:26, November 11, 2006.

I agree with the merger - the DBR article is the best way to cover the theory - it's not a very large article currently. The fibre applications could usefully be a section of that article. It would make sense to retain the redirect though. JohnGray 13:35, 11 November 2006 (UTC)

I oppose merging FBG and DBR. DBR can be in planar waveguide, as a dielectric mirror, or in fiber. FBG is only in fiber. Olegivvit 10:05, 14 November 2006 (UTC)
 * Would you have a problem then with merging into the DBR article? FBG's can then be treated in that article as a special case.--Srleffler 13:15, 14 November 2006 (UTC)

I oppose - FBG's are a topic all on their own due to their unique practical applications. --PeterMarkSmith 11:15, 15 November 2006 (UTC)
 * I agree they're a topic of their own - but I'm not sure that it's a topic with enough content (yet) to keep them split. The theory is the same - the applications may be different but we don't have much on the applications at present To me, the merger seemed a way to make things a little more straightforward, but I don't object to keeping them separate if more FBG stuff is in the pipeline. JohnGray 18:22, 15 November 2006 (UTC)

Working on it
Hi,

Please hold off on the merger, I am putting together a lot of material om FBGs so I would like to have a go at a major increase in size (yes with lots! of references).

I will also add to DBR, which are separate to FBGs, specifically in their manufacture and applications.

FYI I am a currently working in the field of FBG sensors, and have done some work on DBR for VCSELs. Grahamwild 17:15, 24 January 2007 (UTC)

- requesting addition to the Tilted BFG section. "The angle of tilt in a TFBG has an effect on the reflected wavelength, and bandwidth." What is that effect? Even a very general description. —Preceding unsigned comment added by 158.12.37.51 (talk) 14:26, 14 February 2008 (UTC)

Chiral-fiber Gratings
I removed the following new section from the article, and put it here for review. The editor who posted it appears to have a conflict of interest, and this text should be reviewed prior to inclusion in the article. If the material is suitable, or can be rewritten to be suitable, someone other than the editor who wrote it should reinsert it into the article. --Srleffler (talk) 05:07, 19 June 2009 (UTC)

Chiral-fiber gratings are a variation on conventional fiber Bragg gratings. Rather that write gratings on glass, chiral gratings are mechanical gratings microformed into glass. Chiral Photonics, a New Jersey company, is the leading developer of this technology.

Chiral optical fibers are produced by twisting fibers as they pass through a miniature oven to create a periodic structure. There may be as many as 25,000 twists per inch. Twisting concentric birefringent fiber preforms or nonconcentric fibers, respectively, produces stable structures with double- or single-helix symmetry. While double-helix structures are polarization sensitive, single-helix structures are insensitive to the incident polarization, enabling fabrication of gratings. These fibers are useful as sensors, in-fiber polarizers, lasers, and filters. Twisting uniformly heated standard single mode fiber with residual nonconcentricity also produces long period helical fiber gratings, comparable to conventional long-period fiber grating.

Importantly, as opposed to conventional fiber Bragg gratings that require photosensitive glass, chiral-fiber gratings are media agnostic. They can be implemented in any material that can be drawn. This technology, thus, may widen the current field of resistances and sensitivities available to fiber optic sensing. In order to resist temperature, radiation or chemical corrosiveness certain materials might be used. In contrast, in order to sense temperature, radiation or chemicals, different ones might be.

Re: Obviously chiral gratings should be re-inserted somewhere under long period gratings - it is a legitimate grating (I dont like the word chiral personally) playing a role not unlike rocking filters and does have some benefits. It may need some editing to remove the preception that it is selling itself as superior - otherwise it is not a bad article and is relevant. Many fibre Bragg gratings do not require photosensitivity so that statement is highly limiting and reflects some ignorance of the field. Many femtosecond gratings can also be classed as "mechanical gratings" I note! Regards, JC Australia —Preceding unsigned comment added by 129.78.32.22 (talk) 04:30, 13 March 2011 (UTC)

Bragg Bandwidth Theory
I've just come across this article and while much of it is good, I think there is a problem with some of the equations. The Bragg bandwidth is only independent of length in the strong grating limit. More generally, the bandwidth depends on both the length and the variation in the index. In the weak grating limit, the bandwidth depends only on the grating length and not the index variation. In addition, further clarification would help for some of the equations. For example, $$N$$ and $$B$$ are not defined. I am a professional physicist and am happy to try to improve the article, but will defer to a seasoned Bragg grating expert if one is available and wants to take a look. Flagged up in the article to warn other users of the potentially misleading equation.

Humidity sensing
A recent article in Symmetry Magazine described how a fiber Bragg grating can be used as a humidity sensor:

http://www.symmetrymagazine.org/article/detectors-in-the-dirt

-- Dan Griscom (talk) 23:35, 8 September 2017 (UTC)