Study Of Low Half-voltage And Low Loss PLZT Modulator

In recent years,with the development of the information industry,optical modulators have developed in the direction of high speed,large bandwidth,low loss,and compact size.PLZT electro-optic film is an electro-optic ceramic materialwith high electro-optic coefficient and large refractive index.It has the potential to design and fabricate compact electro-optic modulators with high-speed.In this paper,a PLZT electro-optical thin film is used to design PLZT hybrid optical modulator.The theoretical research,performance analysis,and experimental preparation of the device are emphasized.The etching in the traditional microfabrication process will bring a large loss to the PLZT waveguide,and the fabricated PLZT electro-optic modulator has a large insertion loss.Aiming at this problem,this paper proposes a scheme of a hybrid waveguide of PLZT and silicon based on the basic theory of optical waveguides.The characteristics of high refractive index and low loss of silicon waveguides are used to compensate for the high loss of PLZT waveguides.Based on the theory of traveling wave electrodes,the CPW traveling wave electrode of the device is designed and optimized,.The buffer layer is introduced to neutralize the high dielectric constant of PLZT to increase the bandwidth of device.Simulation results show that when the device electrode length is 10 mm,the half-wave voltage is 10.7 V,the 3 d B bandwidth is 11.75 GHz,and when the input optical wavelength is 1550 nm,the extinction ratio is 28.2 d B,and the insertion loss is 0.6 d B without considering the end-face coupling loss.Due to the low modulation efficiency of the waveguide structure of PLZT as the lower cladding,the study of PLZT electro-optic modulator with graphene electrode was carried out in this paper.Graphene has good optical and electrical properties.It has a low absorption of light and high electron mobility.Compared with traditional electro-optic modulators with metal electrodes,which require a thicker cladding layer to reduce the metal's absorption loss.Graphene as an electrode can be directly deposited on the surface of the core layer to increase modulation efficiency.Simulation results show that the PLZT electro-optical modulation device with graphene electrodes has a switching voltage of 6.2 V and an extinction ratio of 37.5 d B when the input light wavelength is 1550 nm,and the response time reaches nanoseconds.In this paper,we explored the process of graphene transfer and etching,and improved the graphene transfer method.Optical,Raman,and SEM characterization of the transferred graphene were performed.The results show that the method used in this paper can transfer single layer graphene film well.The microfabrication process and graphene transfer method were used to fabrication the device,and the PLZT electro-optic modulation device with graphene electrodes was initially prepared,build a test platform and analyze the test data.