Data_Envelope-free Vernier effect via peak position recognition in cascaded fiber Bragg grating sensors for high-sensitivity sensing

This paper proposes a novel envelope-free peak position recognition method, combined with cascaded FBGs to achieve over 86-fold sensitivity enhancement, verified by temperature sensing experiments.

Notably, the limit of detection of the sensor is reduced by 39.33% compared with single bare FBG (without Vernier effect), outperforming the traditional optical Vernier method. Without the need for an additional physical reference arm sensor, this method features simple implementation, controllable cost and flexible performance tuning. Building on our prior virtual Vernier framework, this work first extends the envelope-free Vernier strategy to cascaded FBGs, breaking the inherent barrier of FBG sensing and offering a low-cost flexible scheme for high-precision fiber measurement.</p>