An excessively tilted LPFG-assisted surface plasmon polaritons sensor (ExTLPFG assisted SPP sensor) with ultrahigh sensitivity is proposed and numerically investigated using the finite-element-method-based full-vector complex coupled mode theory. We show that the SPP mode is transited (or excited) gradually from both the p-polarized TM0. j and EHv. j (v ≥ 1) modes. https://www.roneverhart.com/RME-Fireface-UFX-III-Audio-Interface-p32300/