Fiber Bragg Grating Sensor Series

Fiber Bragg Grating (FBG) sensors are classified based on grating structure, wavelength response, and application, including uniform, chirped, tilted, and long-period FBGs.Overview of FBG SensorsFBG sensors are optical fiber-based devices that reflect specific wavelengths of light while transmitting others, with the reflected wavelength shifting in response to environmental changes such as strain, temperature, or pressure . They are widely used in structural health monitoring, aerospace, environmental sensing, and biochemical applications due to their high sensitivity, immunity to electromagnetic interference, and ability to operate in harsh environments .Types of FBG SensorsUniform FBGsThese have a constant grating period along the fiber length.They reflect a narrow wavelength band and are commonly used for precise strain and temperature measurements .Chirped FBGs (CFBGs)The grating period varies along the fiber, producing a broader reflection spectrum.Ideal for applications requiring dispersion compensation, distributed sensing, or measurement over a range of strains or temperatures .Tilted FBGs (TFBGs)The grating planes are tilted relative to the fiber axis.They couple light from the core to the cladding modes, making them sensitive to refractive index changes and suitable for chemical or biochemical sensing .Long-Period FBGs (LPFBGs)These have a grating period much longer than standard FBGs, typically hundreds of micrometers.They couple light from the core to cladding modes, producing attenuation bands rather than reflection peaks, and are used for sensing strain, temperature, or bending over longer distances .Polarization-Dependent FBGsDesigned to respond differently to different polarization states of light.Useful in applications where polarization effects are critical, such as in fiber optic gyroscopes or advanced structural monitoring .Multi-Parameter FBGsThese combine multiple gratings or specialized designs to measure more than one parameter simultaneously, such as strain and temperature, often using compensation techniques to isolate each effect .ApplicationsFBG sensors are extensively used in civil infrastructure monitoring, aerospace, and industrial environments. They can measure strain, temperature, pressure, vibration, and even chemical changes, with the choice of sensor type depending on the required sensitivity, measurement range, and environmental conditions . In summary, the selection of an FBG sensor type—uniform, chirped, tilted, long-period, or multi-parameter—depends on the specific sensing requirements, including the physical parameter to be measured, the desired sensitivity, and the operational environment.