parameters.txt

cudos实例

!       CUDOS Fibre Software sample parameter file
! This parameter file is for finding the first modes of 
! fibre used as an example in "Multipole method for 
! microstructured optical fibers. I. Formulation", 
! by T.P. White, B.T. Kuhlmey, R.C. McPhedran, D. Maystre
! G. Renversez, C. Martijn de Sterke and L.C. Botten,
! J. Opt. Soc. Am. B/Vol. 19, No. 10, pp. 2322-2330 (2002)
! The structure consists of a single layer of hexagonally 
! arranged air holes in a dielectric background with 
! refractive index 1.45, the whole structure being surrounded
!  by a slightly lossy 
! jacket. 
! The structure is by an external file, and
! symmetries are ignored.
!
! First define the structure :
! Load the externaly defined structure file.
! Note that the internal structure compiler can only deal 
! with fibres having C6v symmetry properties

load structure file=nosymhex.txt

! define the wavelength
lambda=1.45

!define the region of effective indices in which to search for modes:
n_eff_0=(1.427,0d0)			! lower left corner of the region
upper right n_eff corner=(1.446,1d-2)	! upper right corner of the region

! adjust the eigenvalue threshold (when no symmetries are used, degeneracies occur, in which case 
! the two degenerate eigenvalues have a larger minimum magnitude than what can be reached 
! for non degenerate eigenvalues
eigenvalue threshold=1d-8

! redefine the number of points to be computed for the 
! initial determinant map: this number is very large in
 ! the present example. Indeed the region of effective 
! indices is quite large (we want to get the first 7 modes).
! Further when no symmetries are used,
! modes can not be separated by their class of symmetry. 
! They tend to be quite close together, and we therefore need a good resolution in the 
! initial determinant map
! 
num_n_points=500 	! number of points along the real axis (default is 100)
num_ni_points=8		! number of points along the imaginary point (default is 4)

! define the range of classes of symmetry to be scanned. 
! When no symmetries are used, the only valid class of
! symmetry is 1

start_mode=1
stop_mode=1

! Start searching modes
search modes

! End of parameter file
end