【摘要】 结合铌酸锂薄膜的研究现状,提出一种硅与铌酸锂复合集成的波导结构,该波导结构能够将硅基的成熟工艺与铌酸锂材料的特性结合,利用铌酸锂的高双折射特性,该波导结构在实现偏振控制器件方面具有一系列独特的优势.基于硅与铌酸锂复合的波导结构,设计了两类无源器件:定向耦合型偏振分离器和定向耦合型偏振分离转换器.分别采用光束传输法(BPM)和时域有限差分法(FDTD)对两类器件进行了仿真与性能分析,仿真计算结果表明,偏振分离器能够实现TE模和TM模的分离,且消光比高于30dB,在保证消光比大于10dB的情况下,其带宽约为70nm,工艺容差达100nm;偏振分离转换器能够实现TM模向TE模的转换,且消光比达20dB.两类器件均具有尺寸小、结构简单、工艺上易于实现等优点.更多还原

【Abstract】 With the research status of lithium niobate thin film,we propose a Silicon-Lithium niobate hybrid integrated waveguide which could combine the mature processing technology of Silicon with the properties of lithium niobate.Utilizing the high birefringence of lithium niobate,the Silicon-Lithium niobate hybrid integrated waveguide has a series of unique advantages in the design of polarization control devices.Based on the Silicon-Lithium niobate hybrid integrated waveguide,we proposed two types of passive devices.The first one is polarization besm splitter(PBS)based on directional coupler(DC)which could achieve the separation of the TE and TM mode with a relatively simple structure.Then the beam propagation method(BPM)is used to simulate and analyze the performance of the device.The numerical simulations show that the device has a good performance for the separation of TE and TM po-larizations with a high extinction ratio(higher than 30dB).The simulated fabrication tolerance for the variation of the waveguide width is about 100 nm and the bandwidth is about 70 nm when the extinction ratio is higher than10 dB.This decive can avoid complex structure and make the design simpler because of the high birefringence of lithium niobate.The other one is polarization splitter-rotator(PSR)based on directional coupler(DC)which could achieve the separation of TE and TM polarizations and the rotation of the TM polarization.The finite difference time domain(FDTD)method is used to simulate the performance of the device.The simulations show that the device has a good performance for the separation of TE and TM polarizations and the rotation of the TM polarization with a high extinction ratio(higher than 20dB).Since the Silicon-Lithium niobate hybrid integrated waveguide is asymmetrical in the vertical direction,this device can also avoid the complex structure and be achieved with a relatively simple.Both of the two devices have the advantages such as small size,simple structure and easy to be achieved.更多还原