Study Of Three-dimensional Mode Converter Based On Polymer Waveguide

Optical communication network plays a key role in telecommunications to support the internet infra-structure.With enmerging of the huge amount of bandwidth-hungry devices and the increasing computational power which follow the Moore's law,the data traffic of the internet in the past ten years has sustained in exponential growth in the past ten years.And for the foreseeable future,the speed will continuely raise fast.In the past two decades,we met the internet traffic date demand mainly by using wavelength dividsion multiplexing?WDM?system.The using of WDM system greatly broaden the information transmission capacity.However,it is well known that the transmission limit can not exceed Shannon limit and all this WDM system is based on single mode fiber light,with the development of the technological progress,only using WDM system can not met the explosive growth of the transport capacity.So,we need to expand new dimensions such as polarization state,mode and phase etc.To match the new applications,recently,mode division multiplexing system?MDM?have attract more and more attention which can provice another dimension for transmission capacity expansion.In this paper,we systemically compute and stimulate many kinds of mode converter,moder mux/demux system and muti-port optical switch to expanded information capacity both in port numbers and modes type.And we complete analysis,design mask and fabricating device using eching and wet process,then we compared those device.The paper mainly including the following parts:1.Design and fabrticating one kind of unbiasd 1×4 optical switch,this device can expand the data capacity by control the electric signal on the electronic.Then by controlling the on/off state in the electrode to control light output from different ports,the light can output form port 1-4 respectively.We use SiO₂ as under cladding to improving speed of this switch.By using polymers as core and clading material and etching air tank structure to reduce the power waste,we use finite element method comparing different substrate such as PMMA and silica and also comparing the device power waste with have and have not the air trench structure.And we also design and fabricating then testing the device.We use scanning electron microscope?SEM?to characterization this device.The testing results shows that the etching effect is excellent,and change of the near field light spot is very clear when the electrode work,which means that the switch port conversion effect is good.We characterized the device by by an oscilloscope DPO4104B.The square wave shape is good.And rise and fall time of the switch is 160 us and 80 us respectively.The power comsumption is 6 mW.2.We designed one kind of vertical coupled mode converter and one kind of mode muti-mode mux/demux system,the device adopted an X vertical coupled structure.The mode converter being designed,upper core and under core dimension differs eath other.The mode converter can convert mode LP₀₁ to LP_11a,LP_11b,and LP_21a1a mode.And by rational combining the mode converter we design one mode mux/demux device which can mux and demux LP₀₁,LP_11a and LP_21a1a mode with converting ratio higher than 99%.3.We design one kind of mode converter switch array,mode converter combining with optical swith to achieve the function of 15 combination of mode LP₀₁,LP_11a,LP_11b1b and LP_21a1a mode and control it's on/off state with maximum power consumption of only18mW.In this section,we give the detailed calculate results.The device can be used in MDM system by bonding with fiber or waveguide mode mux/demux system and to build up complete MDM communication system.