In this study, the V –I transmission matrix formalism(V –I method) is proposed to analyze the spectrum characteristics of the uniform fiber Bragg grating(FBG)-based acousto–optic modulators(UFBG-AOM). The simulation results demonstrate that both the amplitude of the acoustically induced strain and the frequency of the acoustic wave(AW) have an effect on the spectrum. Additionally, the wavelength spacing between the primary reflectivity peak and the secondary reflectivity peak is proportional to the acoustic frequency with the ratio 0.1425 nm/MHz. Meanwhile, we compare the amount of calculation. For the FBG whose period is M, the calculation of the V –I method is 4 ×(2M-1) in addition/subtraction,8 ×(2M- 1) in multiply/division and 2M in exponent arithmetic, which is almost a quarter of the multi-film method and transfer matrix(TM) method. The detailed analysis indicates that, compared with the conventional multi-film method and transfer matrix(TM) method, the V –I method is faster and less complex.
