Wavelength Stabilization and Intensity Correction of Fiber Fabry–Pérot Tunable Filter-Based Wavelength-Swept Laser

Wavelength-swept laser (WSL) is a light source for sensing dynamic physical quantities in optical fiber sensors and has the advantage of a fast scan speed over a wide wavelength range. However, WSLs based on the fiber Fabry–Pérot tunable filter (FFP-TF) have difficulty maintaining a stable scanning wavelength band due to its thermal instability. Additionally, fluctuations in the intensity of the WSL due to temperature variations in the gain medium within the WSL resonator affect the accuracy of the sensor. In this study, we report two approaches for FFP-TF-based WSL stabilization. First, we implement a feedback mechanism to stabilize the center wavelength of the WSL by adjusting the voltage of the FFP-TF based on measurements in the temporal domain. Second, we propose a method to rapidly measure the signal in the temporal domain and compensate for intensity variations due to the temperature changes in the gain medium. The effectiveness of the proposed WSL stabilization and amplitude correction techniques was evaluated using a set of five fiber Bragg gratings (FBGs) maintained under consistent conditions. Over a measurement period of 15 h, the wavelength stability of the WSL was confirmed to be within a maximum standard deviation (SD) of 66.7 pm. Additionally, the peak intensities of the FBGs were successfully corrected for fluctuations due to the temperature changes in the gain medium. These results demonstrate the effectiveness of the method in maintaining the precision and stability of a WSL output over a long period of time and should enable rapid and accurate measurement of the wavelength and peak intensity of FBG-based sensors.