The Research Of Mode Selective Switch Based On Tapered Fiber And Spatial Light Modulator

With the rapid development of the Internet in recent years,the growth of audio and video is explosive,which poses new challenges to the transmission capacity of optical communication technology.In order to continuously improve the transmission capacity of fibers,researchers have designed and implemented multiplexing technologies in different dimensions.Therefore,TDM,WDM,and current research hotspot-SDM have emerged.As a kind of SDM,MDM has increased the transmission capacity of fiber and added a new information exchange granularity-mode.Based on the MDM,this paper proposes and designs a mode selective switch based on tapered fiber and SLM.Further,two or more multiplexing technologies used in the transmission system will increase the capacity,such as WDM-MDM.In order to make the mode selective switch still applicable,the function of operating the wavelength of the switch is increased.Therefore,the switch can realize the separation of the mode and wavelength while maintaining states unchanged and separately distribute the separated beams to different path.The innovation and main work of this paper are as follows:1.A scheme of mode separation without conversion based on tapered fiber is proposed.This paper applies tapered fiber to the mode selective switch,which breaks through the limitation that the demultiplexer must perform mode conversion while separating fiber modes.This article explains the principle of the switch and analyzes the results through the software platform.In tapered two mode fiber,more than 95%of the LP,core mode energy is transformed into the cladding mode.Therefore,spatial modes' distribution between LP01 mode and LP11 mode would be separated without conversion.2.A scheme of path allocation for mode/wavelength based on SLM is proposed.Path allocation is realized by loading different blazed gratings on corresponding areas,so that the beams with different mode or wavelength witch irradiate on different areas of the SLM would be modulated with different reflection angles.This gives the switch more flexibility.3.The switch simultaneously operates the mode and wavelength of the beam.This switch realizes the function of the wavelength selective switch at the same time.The beam' state of mode and wavelength is unchanged.This allows the switch can be applied to the WDM-MDM network without the need for new conversion devices,reducing loss and network construction costs.