nHi GWANG,nThank you! I have solved this question in this transmission by your method.n But when I change a parameter to get a new transmission, I meet a new problem.nThere is a warning that Insufficient number of peaks detected to calculate free spectral range.nThe FSR is 0:nnquality factor is a point :nnI decrease the pit excursion from 7 to 3nThe problem still exists.nCan you tell me how to solve this problem?n