High sensitivity fiber Bragg grating (FBG) sensor based on hollow core silica tube (HCST) sensitization for gas pressure and temperature discrimination

•A high temperature resistant ceramic adhesive (HTA) enclosed fiber Bragg grating (FBG) sensor for simultaneous measurement gas pressure and high temperature is proposed;•A mathematical relationship between pressure sensitivity, Young's modulus and temperature has been established and the relationship between the Young’s modulus of HTA and temperature has been determined.•Taking advantage of the temperature resistance property of HTA, the proposed fiber structure has a high working temperature up to 400 °C. The pressure sensitivities of the encapsulated are linearly proportional to the temperature which start from zero at room temperature and become more negatively sensitive with increasing temperature.•An interest approach based on 2 × 2 characteristics matrix has been demonstrated for discriminative measurement of pressure and temperature is proposed.