Recent content by Gilbert

Edit : is there any book or website that could explain the behavior of FBG with multimode fiber ?

Hi everyone! I use a FBG in a double-clad multimode optical fiber of 20 µm core diameter, and a laser diode working at 910 nm as ligth source. As the Bragg reflection wavelength of a FBG depends on the effective refractive index of the different guided modes (λFBG=2.neff.Λ , where Λ is the...

As you can see on the picture above (http://en.wikipedia.org/wiki/Gaussian_beam#mediaviewer/File:GaussianBeamWaist.svg), θ is the far field divergence. Thus : θ=limz→∞{ω(z)/z} , and it is the theoretical maximum divergence. And ω(z) = ω0 √(1+z²/ zR2) . It comes from the resolution of the...

θ is the half-angle divergence for z→∞ so that : θ=limz→∞ {ω(z)/z} = ω0 / zR = λ/(π.ω0) with zR = π.ω02 / λ : the Rayleigh range.

I think there is a mistake in your equation : (A-B)∪(A-C) ≠ (A∩B)∪(A∩C). Here it's a general example to verify it: A={a,b,c,d} , B={a,c} and C={c,d} A-(B∩C) = {a,b,c,d} - ({a,c}∩{c,d}} = {a,b,c,d} - {c} = {a,b,d} And (A-B)∪(A-C) = {b,d}∪{a,b} = {a,b,d} Then : A-(B∩C) = (A-B)∪(A-C). But...

I am currently completing a Master's degree in Electronics Engineering in France. I am comfortable with electronics, photonics and instrumentation in general. I signed up because I think it is a good opportunity to learn and discuss about subjects I have few knowledges, with people from around...