Laser-welded high-stability all-silicon dual-cavity MEMS Fabry-Perot pressure sensor with self-temperature...

This Letter presents a laser-welded all-silicon dual-cavity MEMS Fabry-Perot sensor operating from 0.5 kPa to 3.5 MPa over a temperature range of -40 to 125 °C. Adhesive-free laser-welded integration and encapsulation of the sensor chip and optical fiber ferrule are achieved using a carbon dioxide laser, enhancing structural reliability. Compared with previous all-silicon dual-cavity FP sensors, the key advance of this work lies in the laser-welded fiber integration, which suppresses thermally induced cavity drift and enables stable pressure-temperature decoupling over the full operating temperature range. Temperature sensing is realized through the combined thermo-optic and thermal expansion effects within the silicon substrate cavity, while pressure is determined based on the pressure-sensitive response of the vacuum cavity. To mitigate cross-sensitivity, a piecewise linearization method is employed for pressure-temperature decoupling and in situ temperature compensation. At 125 °C, temperature compensation improves pressure accuracy from 0.404% FS to 0.195% FS during pressurization and from 0.398% FS to 0.062% FS during depressurization. These results demonstrate the potential of the proposed sensor for reliable pressure sensing over a wide temperature range.