Fabrication Of Bragg Grating In As₂S₃ Chalcogenide Glass Fibers

The chalcogenide glass material has high nonlinearity and good light transmission in middle-and far-infrared band,and can be used widely in near-and mid-infrared region.The chalcogenide glass photonic devices will be used in the fields of communication and medium infrared sensors,nonlinear signal processing and fiber lasers,etc.The chalcogenide glass fiber Bragg grating is a important photonic devices.When it was fabricated as a linear device,can be used for infrared sensor;but as a nonlinear device,can be applied to all-optical switching,pulse shaping,and also can improve the generation of supercontinuum and slow down the speed of light,etc.First,in this paper,the As2S3 chalcogenide glass fiber Bragg grating is simulated by the coupled mode theory,then the reflection spectrum,transmission spectrum,the power conversion and the relationship between peak reflectivity and refractive index modulation.Then,the As2S3 chalcogenide glass fiber Bragg grating was fabricated in the experiment.The Fiber Bragg grating writing by the use of a near bandgap light at 532 nm and improved Sagnac interferometer system with +1/-1 diffracted orders phase mask has been demonstrated in two different cladding(~170 ?m and~140 ?m)As2S3 chalcogenide fibers.We analyze the dynamic characteristics of two different cladding As2S3 chalcogenide glass fiber Bragg grating in detail,including transmission spectrum and transmission peak.In addition,we also analyze the photosensitivity of smaller diameter(~140 ?m)fiber,and the refractive index modulation amplitude and the average refractive index are obtained.