Research On High Speed Optical Switch Based On Electro-optic Mode Deflection Of LN Waveguide

Human demand for the capacity of communication system has accelerated the development of all-optical switching network.Optical switches,as the core equipment of all-optical switching networks,play a significant role in optical routing and optical interconnection,which is widely used as a routing selector,a wavelength selector,and an optical ccross-connect device in optical communication system.In a word,there is no communication network without a switch.Starting from the telephone switching network,switches have been widely applied to implement circuit switching between users.Optical signals of different wavelengths must use optical switch in order to implement routing in all-optical networks.Mechanical optical switch based on fiber collimator and micromirror relying on the movement of components in the optical path,and generally exist the problems of long switching time and poor repeatability.Optical switch based on planar optical waveguide technology have become a crucial direction for the development of optical switches due to its features such as small size,easy integration,flexibility and reliability,combined with the excellent electro-optical effect of lithium niobate materials to change the refractive index of waveguides that can achieve fast and stable switching of the optical path.In previous work,we have known that the design of lithium niobate optical waveguides and microstructured electrode arrays can produce larger mode deflections.the principle is that: when an external voltage is applied to the microstructured electrode,it would bring changes in the spatial distribution of the electric field,resulting in a spatial distribution of refractive index changes,thereby guiding the optical waveguide mode to achieve deflection.Based on the theory of electrooptic effect,this paper proposes and attains a 1×2 miniature high-speed optical switch based on Xcut lithium niobate proton exchange waveguide and electro-optic deflection device.The optical switch device combines the design structure of an isosceles triangle array electrode,a horn-shaped input and two tapered output waveguides.The structured is mainly constituted by four parts,the first three parts are used to realize the optical field mode deflection under the electro-optic effect,and the fourth part introduces regular lateral taper output waveguide for implementing 1×2 mode optical switch based on the electro-optic deflection.Experiments have verified that when the incident light is 1530 nm,the intensity modulation of the light field can be achieved.The response time of the switch is 22 ns,switch contrast is 14.58 d B.The optical switch is implemented based on the principle of electro-optic mode deflection.The difference from an electro-optical switch based on a Mach-Zehnder interferometer is that the 1×2 optical switch is a non-interfering structure and may be realized in a relatively large wavelength range High-speed switch switching of broadband optical;its two-mode output can be used in modular division multiplexing technology for increasing the communication capacity,which is also an innovative point of the 1×2 high-speed optical switch design.When analyzing the experimental and theoretical simulation results of the 1×2 optical switch,it was brought by the structure design are relatively high switching voltage and low switching contrast.Therefore,the optical switch is improved in design,and the waveguide design of the electrode part of the improved 1×2 optical switch is designed to have a width gradient of 8-80 ?m,and the covered electrode structure is the same as the waveguide structure,forming a gradient isosceles triangle array electrode structure.Theoretical research on the optical switch of the designed graded waveguide electrode structure,and using HFSS(High Frequency Structure Simulator)software to explore methods that enable to achieve bandwidth and high-frequency work.After optimation,the switch contrast is 25.69 d B.Until now,the simulation research and preparation have been completed,and the device preparation completed,but due to time constraints,its experimental part didn't finish.