IdealPhotonics' long-period fiber grating is an optical device that achieves core-cladding mode coupling through periodic refractive index modulation (period 100μm-1mm). It utilizes the transmission loss peak (depth > 20dB) at the resonant wavelength (bandwidth 10-50nm) to achieve broadband sensitivity (sensitivity > 100nm/RIU) for strain, temperature, and refractive index, making it suitable for gain flattening and multi-parameter sensing in fiber optic communications."Claddding mode holographic manipulation" achieves broadband coupling (bandwidth 30nm, sensitivity 200nm/RIU) of the core-cladding mode through precise periodic design (Λ=100-500μm). It supports decoupled measurement of multiple parameters such as refractive index (resolution 10⁻⁶ RIU) and bending (curvature 0.1m⁻¹), providing all-fiber sensitive probes for cutting-edge fields such as biochemical microfluidics and smart skin.