Research On Silica/SU-8 Hybrid Integrated Optical Switch Devices

In recent years,due to the demand for fast and efficient transmission characteristics,optical communication technology has received extensive attention and has been rapidly developed.While pursuing better optical transmission performance,signal processing is also required,which makes various optical devices widely used.Among the optical devices,the planar optical waveguide device is small in size,has a relatively close internal structure,and has a relatively simple integration process,which can play an important role in short-distance communication scenarios.In this field,the use of organic materials and inorganic materials has its own advantages and disadvantages-organic materials are easy to electro-optical and thermo-optical modulation,and inorganic materials have relatively lower losses,but a device made of a hybrid of the two can combine the advantages of both,while reducing the two Therefore,the future application and development space of this planar optical waveguide device will be very wide.In this paper,we study the hybrid integrated optical switch device of silicon dioxide/SU-8.The waveguide structure of the designed optical switch device adopts the embedded strip waveguide structure,and the polymer material SU-8 2002 is selected as the core layer.It is filled into the groove with silicon dioxide as the lower cladding layer,and the core layer material overflowing the groove is etched away to form a rectangular waveguide recessed into the lower cladding layer,and then the PMMA upper cladding layer is spin-coated.The sidewall of the waveguide obtained by this manufacturing step is steep,which basically solves the disadvantage of irregular shape of the inner core caused by wet etching,so that a photonic chip with higher performance can be fabricated.Based on the embedded strip waveguide structure,the modeling design and performance simulation of 2×2 optical switch units based on “DC-MZI” type and “MMI-MZI” are carried out respectively.The size of the two optical switch units is smaller than 0.05mm×9.8mm,simulate the adjustment of the modulation arm temperature,change the working state of the switch,simulate the “Cross” and “Bar” states respectively,and obtain good performance indicators,the insertion loss is less than 0.049 d B,and the extinction ratio is greater than 35 d B.The modulation power consumption is less than 2.82 m W.After discussing the 2×2 optical switch units based on the two new structures,multiple designed 2×2 optical switch units are cascaded to obtain two hybrid integrated 4×4 optical switch arrays based on embedded strip waveguide structures.The performance of the array is simulated separately,and by adjusting the temperature of multiple groups of modulation arms,the light entering from 4 arbitrary input ports can be exported from 4 arbitrary output ports,while maintaining the high performance of the designed structure.array function.On this basis,the dimensions of the two 4×4 optical switch arrays are both smaller than 0.15×29.2mm.The temperature adjustment of each modulation arm is simulated to make it work from any input port to any output port,and the insertion loss is equal to Less than 0.121 d B,the modulation power consumption is less than 11.29 m W.The proposal and design of the above optical switch devices have great application potential in the fields of optical communication and optical crossover,especially in the production of large-scale optical switch arrays.In this paper,in addition to the discussion on the structure of the embedded strip waveguide optical switching device,the structure of the raised strip waveguide optical switching device is also studied.The raised strip waveguide structure is spin-coating of the core material SU-8 2002 on a silicon dioxide substrate,and the core layer part attached to the silicon dioxide is formed by mask exposure,and wet-processed during the development process.The core layer material that does not need to be retained is removed by etching,and then the PMMA upper cladding layer is covered on the top layer of the waveguide core layer and the surface of the silicon dioxide of the lower cladding layer.Based on the raised strip waveguide structure,the 2×2 optical switch units and 4×4 optical switch units based on “DC-MZI” type and “MMI-MZI” type were redesigned respectively under the condition of keeping the original device parameters as much as possible.Optical switch arrays are designed and simulated.Then,the various parameters and performances of the raised strip waveguide optical switch device and the embedded strip waveguide optical switch device were compared horizontally and vertically,and the advantages and disadvantages of the optical switch device based on the two structures were discussed respectively.The devices that are more suitable for mass production are designed and expanded to obtain parameters suitable for fiber arrays（FA）.On the basis of many theoretical analyses,the feasibility analysis and experimental parameter exploration of the application of the above designed silica/SU-8 hybrid integrated structure were carried out.In this paper,the process flow of embedded strip-shaped waveguide structure,raised strip-shaped waveguide structure and aluminum electrode is also given.After formulating a specific preparation plan,through a large number of experimental evidences,the real parameters of spin coating,pre-baking,exposure,post-baking,development,etching and other related process processes were explored,and the manufacturability of the design was fully confirmed through real operations.