AWG-Based Interrogator for FBG Sensors

In this work, we have made an interrogator for fiber optic sensors based fiber Bragg grating using a broadband radiation source and a spectrometer, implemented on a photonic integrated circuit (PIC). The basic spectral element of the interrogator is PIC based on arrayed waveguide grating with 10 crossed channels. The chip is made on the basis of indium phosphide. The advantage of the proposed scheme is complete passive realization, which makes it possible to increase the interrogation rate. A semi-analytical demodulation algorithm was proposed for wavelength measurement, the error of which is less than a picometer. In this work the different factors such as device temperature and polarization state affecting the wavelength measurement error were analyzed. The main contribution to the error is connected with the polarization properties of elements used, since the chip is made for one polarization. The absolute wavelength measurement error of the developed interrogator is estimated as 67,6 pm.