The Study Of High Speed Silicon-Based Optical Buffer

All-optical network is the core of the next-generation communications technology.Its construction lies in the realization of all-optical switching technology,including data exchange,routing,buffering,and forwarding.Currently,significant advances have been made in the application of optical switching,optical routing and optical forwarding technologies.Only the optical buffer technology can be promoted,all-optical networks can truly provide services.Due to the current bottleneck of“opto-electrical-to-optical”conversion,the buffer cannot be moved from the electrical buffer to the optical buffer.Therefore,it is very important to study all-optical caching.According to the different buffer media,the optical buffers are mainly divided into optical fibers and waveguides.Fiber-optic buffers can achieve a considerable amount of delay,but are susceptible to environmental influences,and are sensitive to external disturbances such as temperature,and the large device size makes it difficult to control the buffering time.Waveguide-type buffers are easy to integrate on-chip thanks to the compact structure of the waveguide structure,and the buffer time is precisely controllable.By the reasonable design of the micro-ring resonant cavity can also achieve a large amount of delay.Based on the previous results,this paper proposes an improved buffer structure,which achieves low power consumption,large delay,and tunable operation while satisfying the on-chip integration.In this paper,a low-power polymer thermal tunable track-type optical buffer on a silicon substrate is designed based on theories of dielectric slab waveguide theory,micro-ring resonator coupling theory,group delay theory,thermo-optic effect and optical switch working theory.Light can achieve single-mode transmission through this structure to reduce the device loss,by virtue of the resonant effect and the dispersion effect of the waveguide can reduce the speed of light propagation to improve the amount of buffer time,the use of high thermal coefficient of polymer material can make the optical buffer switching time achieve sub-ms level.By analyzing the micro-ring bending loss,coupling efficiency and optimizing the design of the structural parameters,the simulation shows that the respond speed is about600μs,the switching power consumption is 14mW,and the maximum delay is 1.2ns.The overall size of the thermo-optic tunable optical buffer is about 14mm~2.By using spin coating,vacuum coating,UV contact exposure,reactive ion etching,electrode nesting,cutting polishing and other processes,a polymer thermo-optic tunable buffer chip was successfully fabricated experimentally.The spectral characteristics,cache characteristics,response characteristics,and power consumption were tested.Measured device insertion loss was11.2dB,rise response and drop response time were 320μs and 620μs respectively,buffer maximum delay was up to 1.177ns,and the test results were basically consistent with the design results.In order to further improve the response speed of the optical buffer and reduce the chip size,a cascaded electro-optic tunable optical buffer based on silicon-on-insulator(SOI)is designed.With the strong binding of SOI waveguides to light,device integration is greatly improved and the overall size is reduced to 0.005mm~2.According to the simulation results,the driving voltage of the device is 1.5V,and the maximum delay of the optical buffer is 49ps.With the help of the electro-optic modulation technology with the free carrier dispersion effect,the optical buffer response speed can reach 2ns.At this time,the switching power consumption is only 5.7mW.This new type of SOI-based electro-optic tunable optical buffer has low power consumption,high integration,high-speed response,low driving voltage,etc.It can meet the requirements of high-speed optical buffer processing chip.