Composite materials are widely used in the aerospace industry and structural engineering owing to their advantageous mechanical properties. The curing monitoring of composite material is important to ensure the quality of the curing process, especially for the characterization of residual strains after manufacturing. In this study, we present a notched long-period fiber grating (NLPFG) with a period of 650 μm and a diameter of 66 μm that can be used in the curing monitoring of composite materials. This NLPFG was embedded into the middle layers of composite materials in order to determine the curing residual stress exhibited by the materials. The experimental results showed that the residual stress was about 107 MPa and the axial residual strain was 1490 με. Therefore, the proposed NLPFG has potential as a strain sensor for composite materials.
