Dual-Core Side-Hole Fiber for Pressure Sensing Based on Intensity Detection

We propose a novel dual-core side-hole fiber (DCSHF) for air/hydrostatic pressure sensing. Two large air holes are employed in the cross-section of the DCSHF, which result in a difference of the pressure-induced index changes for two fiber cores. The mode coupling between two fiber cores of the DCSHF is sensitive to the pressure-induced index change which ensures the intensity detection of the DCSHF-based pressure sensor. A segment of DCSHF with a length equal to the coupling length of the mode coupling between two fiber cores is used as a pressure sensor. When the light is injected into the central fiber core of the DCSHF, there is a one-to-one correspondence between the pressure and the output power on the output side of the central fiber core. A pressure sensor based on a typical DCSHF can achieve a pressure measurement range of 27 MPa. DCSHFs with different structure parameters for pressure sensing are investigated.