Abstract
A phase demodulation of dual-cavity fiber-optic Fabry-Perot interferometer based on open-cavity and silica-cavity was proposed and experimentally demonstrated for pressure and temperature sensing. In contrast to the commonly used wavelength demodulation, the phase demodulation for dual-cavity fiber-optic Fabry-Perot interferometer used in this paper has the advantages of simplicity, rapidity and high precision. By the phase demodulation in the spatial frequency domain, pressure sensitivity of -2.07 rad/Mpa and temperature sensitivity of -5.48 x 10 -4 rad/°C are obtained for the open-cavity, and pressure and temperature sensitivity are respectively -0.16 rad/Mpa and -1.5 x 10 -2 rad/°C for the silica-cavity. Thus, this structure can achieve concurrent the pressure and temperature sensing as a result of that pressure and temperature sensing characteristics of the open-cavity are different from silica-cavity.
Highlights
In recent years, the fiber-optic Fabry-Perot interferometers have been widely applied to lots of sensing fields, such as transverse load [1], [2], temperature [3], [4], strain [5], [6], refractive index [7], [8], magnetic field [9], [10] et al, owing to their advantages of resistance to electromagnetic interference, compact size, and low weight
EXPERIMENT AND RESULTS High sensitivity pressure sensing can be achieved by opencavity for the reason that gas pressure can change refractive index
The spectra of dual-cavity Fabry-Perot interferometer are recorded by an optical spectrum analyzer (OSA) (YOKOGAWA AQ6370D) as the pressure rising from 0.2 to 1.0 MPa with a step of 0.1 MPa at the temperature of 25 ◦C, as shown in Fig. 5(a) and 5(b)
Summary
The fiber-optic Fabry-Perot interferometers have been widely applied to lots of sensing fields, such as transverse load [1], [2], temperature [3], [4], strain [5], [6], refractive index [7], [8], magnetic field [9], [10] et al, owing to their advantages of resistance to electromagnetic interference, compact size, and low weight. INDEX TERMS Fiber-optic sensor, phase demodulation, Fabry-Perot, temperature, pressure. D. Zhao et al.: Pressure and Temperature Sensor Based on Fiber-Optic Fabry-Perot Interferometer by Phase Demodulation
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