轴向张力作用下As2S3硫系光纤的光敏性及其在Bragg光栅刻写方面的应用

Abstract

Objective Among the many photonic devices, the Bragg grating of chalcogenide glass fibers is important. As a linear device, it can be applied to infrared sensors. In nonlinear optical applications, it can achieve alloptical signal processing. In addition, it is necessary to apply Bragg grating with high reflectivity to obtain efficient integrated chalcogenide glass fiber lasers, such as the distributed feedback Brillouin lasers. For chalcogenide glass fibers, it is complex to write Bragg gratings, mainly because the cladding and core components of chalcogenide glass fibers are similar; thus, both show photosensitivity, resulting in the weak photosensitivity of the fiber core. In our previous study, nearbandgap light close to the absorption edge of the material was selected to irradiate the chalcogenide glass fiber. The fiber core showed high photosensitivity, which solved the weak photosensitivity caused by subbandgap light far from the absorption edge of the material. However, when the fiber is used to write a Bragg grating, the depth of the grating transmission peak is not extended and cannot satisfy the actual usage requirements. This requires methods to further improve the photosensitivity of chalcogenide fibers. Therefore, this study extensively investigated the photosensitivity of chalcogenide optical fibers in tension applied in the axial direction to improve the photosensitivity of chalcogenide fibers and provide a new approach to writing gratings with high reflectivity. The findings provide new ideas and approaches for preparing chalcogenide grating photonic devices and will promote the development of chalcogenide photonics. MethodsThe photosensitivity of chalcogenide optical fibers was determined by measuring the change in the refractive index of the fiber core based on the Fabry -Perot (FP) etalon principle. In this experimental device, an optical fiber clamp with a slider was designed to apply tension, and a continuous dualfrequency Nd∶ YAG laser with a working wavelength of 532 nm was used as the illumination source. After the laser beam was expanded using the beamexpansion system, it was focused onto the sample surface through a