Discussion Forum

I would like to calculate the reflectivity/transmission of an anti-reflection (AR) coating on the facet of a diode ridge laser, but the result is strange. Therefore I reduced the case to a simple case by setting the refractive index of the coating as n_coat = 1 (= n_air): a ridge laser emits from its cavity (n = 3.3) to air. In this simple case, one would expect the reflectivity of the laser facet of R = (3.3-1)^2/(3.3+1) ^2 = 0.29. In the attached model, I defined Port 1 as the input port. Since the output side is air and there is no confined mode, I am not able to use a Port 2 to obtain R and T. I used a method, which might be stupid and/or wrong, to calculate T by T = Power_out/Power_in, Power as defined in “Definitions – Variables” in the attached file. The calculated T and R, as shown in the 1D plot of the attached file, are ridiculous. Could anyone please tell me, in this model, where is my mistake; and, is there a better way to obtain T other than P_out/P_in for my case? Thank you very much.