What spectral distortions occur when the fiber is subjected to lateral squeezing?
When an optical fiber with a Fiber Bragg Grating (FBG) is subjected to lateral squeezing, it experiences a phenomenon known as transverse pressure sensitivity, which leads to distinct spectral distortions.
Here’s what happens:
- Induced Birefringence: The lateral squeezing induces birefringence in the fiber. This means the refractive index of the fiber core becomes anisotropic, with different refractive indices for light polarized parallel and perpendicular to the direction of the applied force.
- Bragg Peak Splitting: Due to this induced birefringence, the single, symmetrical Bragg peak of the FBG splits into two distinct peaks. Each of these peaks corresponds to a different polarization state of the light propagating through the FBG. The separation between these two peaks is directly proportional to the magnitude of the transverse pressure applied.
- Wavelength Shift: In addition to splitting, the centroid wavelength of these two peaks will also shift. This shift is influenced by both the axial strain and the transverse pressure, as well as the photoelastic properties of the fiber.
For applications requiring the measurement of multi-directional forces, including transverse pressure, we offer the OFSCN® Fiber Bragg Grating 3D Force Sensor. This sensor is designed with multiple FBG measuring segments to detect forces from various directions.
Here are some standard images of the product:
You can find more detailed technical parameters on our website: OFSCN® Fiber Bragg Grating 3D Force Sensor.