It will take a lot of computing resources and maybe meaningless. You can simulate various FBG of different distributed parameters using the Ricatti differential equation or other modified transfer matrix method. And you will achieve a high accuracy.

Thanks Sir, for your replied. Please suggest me some related papers.

“ Investigation of a Three-Dimensional Micro-Scale Sensing System Based on a Tapered Self-Assembly Four-Cores Fiber Bragg Grating Probe ” would show how to introduce distributed parameters into the TMM.

“Modified Transfer Matrix Formulation for Bragg Grating Strain Sensors” would give you a original TMM.

Thanks Sir.