For the problems of narrow adjustable range

large loss and low bandwidth accuracy in the optical filter module for traditional fiber-optic communication systems

a large bandwidth linear modulation optical filter based on FBG is designed. The modulation system is composed of a light source

a strain-sensitive Fiber Bragg Grating（FBG）

an adjustable strain structure

and a demodulator. A large-scale continuous modulation of the strain is realized by the screw fine-tuning structure

and the linear correlation between the strain amount and the echo wavelength offset is calculated by the combination of the strain beam and the FBG. The simulation analysis shows the peak reflectance of the reflected light as a function of the reflection bandwidth under different FBG parameters

and the relevant parameters are selected accordingly. We conduct an experiment by continuous changing the force values to test the reflected light power

echo central wavelength and echo spectrum. The results show that for every 0.1 mm change

the average central wavelength shift is 415 pm

and the linearity is high. The linearity is better than 0.98

and the modulation range is 1 545～1 565 nm

which can achieve large-bandwidth continuous linear modulation. In conclusion

the structure can be used in a fiber optic communication system that requires a wide range of continuously adjustable filtering modules

and has certain application value.