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This paper describes an efficient system for the interrogation of miniature all-fiber optic sensors, such as Fabry-Perot
interferometers or Bragg gratings that change their spectral characteristics within a narrow wavelength band, under the
influence of the measured parameter. The signal interrogation is performed by sweeping the laser diode's wavelength
over the narrow spectral band containing information about the measured parameter. The optical source consists of a
standard telecommunication distributed feedback laser diode with integrated elements for thermal control. The laser
diode's sensitivity to temperature is used to cyclically sweep the emitted wavelength for approximately 3 nm. This
allows for integration of FBGs and all-fiber FP interferometers with resonator lengths between 0.3 and 1 mm. The
interrogation system further includes a wavelength reference, which was formed by a Bragg gratings pair that was
temperature stabilized by the miniature Peltier element. The responses of both the optical sensor and the reference Bragg
gratings are simultaneously recorded in time during the temperature-induced wavelength sweep. These characteristics are
further digitally processed to eliminate any amplitude fluctuations and noise. The peaks in both recorded spectral
characteristics are then used to calculate the value of the measured parameter, like for example, strain or temperature.
There is, therefore, no need for additional wavelength measurements, which simplifies the presented system. The
proposed system is built from standard opto-electronic devices and is, therefore, simple, easy to manufacture and costeffective.
The system was tested using a 1 mm long sensing all-fiber Fabry-Perot interferometer for temperature
measurements, and standard Bragg gratings for temperature and strain sensing. The achieved temperature repeatability
was better than 0.5 °C, while the strain reparability proved to be about 10 με . The proposed system is thus appropriate
for various industrial and other applications, requiring cost-effective measurements with optical sensors.
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