Miniature and low-power high-precision FBG interrogator with self-temperature compensation

Abstract

A compact fiber Bragg grating (FBG) interrogator, integrating an arrayed waveguide grating (AWG) chip, photodiode (PD) array, and demodulation circuits within an 85 × 60 × 40 mm 3 volume, has been designed and fabricated. Utilizing what we believe to be a novel three-point demodulation technique, precise center wavelength demodulation is achieved. The conventional thermoelectric cooler (TEC) is supplanted by a look-up table (LUT) in conjunction with interpolation for temperature compensation. Experimental validation confirms the interrogator's wavelength demodulation stability at 0.55 pm and resolution of 1.65 pm. Under ideal conditions, the absolute wavelength demodulation accuracy reaches 2.7 pm. Over an operating temperature range of 10 °C to 60 °C, the absolute wavelength demodulation accuracy is enhanced to within 21.5 pm, representing a nearly 19-fold improvement compared to uncompensated performance. This interrogator, characterized by its diminutive size, low power consumption, high accuracy, and adaptability to varying operating temperatures, holds significant potential for widespread application in FBG sensing domains.