Demodulation system for optical fiber Fabry-Perot sensor

A demodulation system for optical fiber Fabry-Perot sensor comprising:

• a light source;
• a Fabry-Perot sensor configured such that light undergoes multi-beam interference in the Fabry-Perot sensor to form interference light;
• a coupler configured to receive light emitted from the light source and transmit the light to the Fabry-Perot sensor and transmit the interference light formed by the Fabry-Perot sensor;
• a first optical assembly configured to shape the interference light into a linear first interference fringe pattern, wherein the first optical assembly comprises a cylindrical lens or a cylindrical mirror;
• a second optical assembly configured to form a second interference fringe pattern on the basis of the linear first interference fringe pattern;
• a first detector provided in a light path downstream of the second optical assembly and configured to receive a first light signal to form a first light signal curve;
• a second detector provided in the light path downstream of the second optical assembly and configured to receive a second light signal to form a second light signal curve;
• a data collection device configured to receive the first light signal curve from the first detector to generate a first light intensity curve and receive the second light signal curve from the second detector to generate a second light intensity curve;
• and
• a processor configured to receive the first light intensity curve and the second light intensity curve from the data collection device, and calculate a cavity length variation of the Fabry-Perot sensor on the basis of the first light intensity curve and the second light intensity curve,
• wherein the first light signal and the second light signal have a phase difference of 90 degrees.