The Fiber Filter Based On Sms Fiber Structure And Its Research

Optical fiber filter is widely used in optical communication field,such as wavelength division multiplexing(WDM)system and time-division multiplexing(OTDM)of the ultra-fast mode-locked pulse fiber.Also have broad and important applications in optical fiber sensing,optical information processing,ultra-fast optics,laser-guided,industrial processing,even in the medical and other fields.In recent years,more and more researchers added to the study of fiber filters,because of the advantages of their tunable,low insertion loss and easy integration with the optical fiber communication systems,it has become an important research on optical fibers.For the single-mode-multimode – single-mode(SMS)structure,based on multi-mode fiber interference theory and self-image effect,attracts widely attention.This paper studies the properties of the structure of the fiber-based SMS bandstop,bandpass filter,research the filtering effect based on UV radiation.This paper first studies on the transmission mode that exist in the multimode fibe ofr SMS structure,then calculate the coupling coefficient between the fundamental mode of the single-mode fiber and the conduction mode of the muliti-mode fiber,so as to realise the transmission spectrum of the whole SMS fiber structure simulation.Then research on the band-pass,band stop filter base on the SMS fiber structure.Focusing on the influence of multimode fiber length in SMS structure for the effect of the SMS structure filter,and fabricate the optical fiber filter based on SMS structure.The characteristics of the fiber refractive index of the multimode fiber can be modulated by using UV radiation,carry out the research on the performance of the fiber filter based on SMS structure by using UV radiation.Study on interaction of various existing SMS structure in the interference pattern and ultraviolet light modulation,simulate the performance of filter based on SMS structrue changes caused by the refractive index adjusting modulated by using UV radiation.Finally based on the theoretical analysis and calculution,we experiment on the theoretical analysis results above.The experiments prove that we can using the UV radiation to realize the filiter performance change.