The parameter “m” is not defined in OptiGrating. However, you can define it yourself in the User Defined option of the Grating Shape function. To get m = 1 you can write 1 + cos(2*pi*x/Period) in the definition box. However, I wasn’t able to reproduce Fig. 10 either. The description specifies some of the grating parameters, but it isn’t clear what the fibre parameters are. I tried using the parameters in Section 2 of the paper. Then used that fibre to calculate what the grating period should be to get a resonance at 1.55 um from an input wave in LP(0,1). The paper says the period is 570 um. I don’t find that to be the grating period for coupling to any of the cladding modes, so it is clear the fibre of Fig. 10 is not the same as that in Section 2. I can’t determine what fibre was used for Fig. 10.