Study Of Photonic Temporal Differentiator In Silicon-on-insulator Waveguides

All optical signal processing for computing and networking has been implemented to overcome the speed limitations generated in the electronics circuits.Photonic temporal differentiator is one of equivalent fundamental devices that form the basic building blocks in electronics,providing the time derivative of the complex envelope of an arbitrary input optical waveform,which has wide applications in optical processing and computing,pulse shaping,optical sensing and control,and all-optically solving differential equations.Based on the available devices and platform in our lab,experimental investigations are carried out with photonic temporal differentiator based on silicon-on-insulator.To improve the device operation bandwidth,a silicon directional coupler is researched.Besides,optomechanical device of racetrack microring resonator through the optical gradient force is proposed as a fractional order photonic temporal differentiator scheme.Main contents are summarized as follows:Firstly,the research background and significance of silicon photonic temporal differentiator are introduced,and the existing schemes are sorted out to find solutions.Characteristics of photonic temporal differentiator have been analysed,so the device operation bandwidth and differential order should be studied.The key parameters to evaluate the performance of a photonic temporal differentiator are processing error and energy efficiency.Secondly,a scheme of terahertz-bandwidth photonic differentiator employing a silicon directional coupler is proposed and experimentally demonstrated.The operational principle of this structure is analyzed mathematically.The relationship between the 3 dB bandwidth of silicon directional coupler and the two variable parameters(the length and the gap)is simulated.Silicon directional coupler is designed and fabricated,and a terahertz-bandwidth first order differentiator is implemented experimentally.Finally,a fractional order photonic temporal differentiator scheme of optomechanical racetrack microring resonator through the optical gradient force is proposed and researched.Optomechanical effect through the optical scattering force or the gradient force is briefly introduced.Operational principle and calculation method on optical gradient force have been analysed.As an alternative regulatory mechanism,optomechanical device of racetrack microring resonator through the optical gradient force is experimental tested.