Numerical and experimental analysis of the modulation of fiber Bragg gratings by low-frequency complex acoustic waves

• Acoustic modulation of the bandwidth of a Bragg grating is numerically investigated.
• Finite element method is used to model a superposition of flexural-longitudinal waves.
• The complex strain induced in the grating is investigated for the first time.
• The net longitudinal strain induces an almost linear bandwidth-voltage response.
• Numerical method allows the control of the grating bandwidth by an electrical signal.

The acoustically modulated bandwidth of fiber Bragg gratings is simulated and experimentally demonstrated. Finite element and transfer matrix methods are used to investigate a superposition of flexural and longitudinal acoustic waves and the induced complex strain in the grating, for the first time. The results show that the longitudinal strain is suitable to generate a bandwidth-voltage response. The modeling is useful for the design and characterization of acousto-optic modulators, which is attractive for the fast control of several photonic devices.