Hi, Steve
I have reproduced Fig. 10 by using matlab based on the numerical method reported by E. Anemogiannis, et al. The fiber parameters are: core radius 2.5μm, cladding radius 62.5μm, core refractive index 1.4573, cladding refractive index 1.45, index modulation amplitude 3.6e-4, grating length 25mm and grating period 570μm. However, the transmission spectrum obtained by using the formulas provided by T. Erdogan presents a large wavelength shift if compared with Fig. 10 (see the figure attached below). Using OpitGrating still cannot get any resonances.
After checking the document of OptiGrating, I think the definition of the grating index profile (see page 26) is very different from that of the paper reported by T. Erdogan, which may be the reason why OptiGrating cannot get the same transmission spectrum as Fig. 10. However, I don’t know how to define the same index profile in OptiGrating as that of Fig.10.
Thanks.
Appendix
grating index profile defined in OptiGrating (page 26): n(x,y,z)=n0(x,y)+Δn0(x,y,z)+Δn⋅P(x,y)⋅A(z)⋅f[Λ(z)⁄cosθ,z]
References
E. Anemogiannis, E. N. Glytsis, and T. K. Gaylord. Journal of Lightwave Technology, Vol. 21, Issue 1, 218-227 (2003)
