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设计了一种基于铌酸锂晶体的电控可调谐波导光栅双波长滤波器。在可同时传输横电波(TE)和横磁波(TM)模式的钛扩散波导上刻写布拉格光栅,能够实现正交偏振的双波长滤波。利用铌酸锂的电光效应改变波导的有效折射率,可以实现两个布拉格波长的快速调谐。对波导光栅滤波性能的分析结果表明,蚀刻光栅在蚀刻坡度小于15°,蚀刻占空比为1/2时,滤波特性最好,且随着蚀刻深度的增加,光栅的反射率与带宽均增加。通过横向电场对波导光栅进行调谐,双波长滤波器的TE模式调谐灵敏度达到15.6 pm/V,TM模式的达到5.5 pm/V。
An electronically tunable waveguide grating dual wavelength filter based on lithium niobate crystal was designed. Bragg gratings can be written on a titanium diffusion waveguide that can transmit both transverse (TE) and transverse magnetic (TM) modes simultaneously, enabling dual wavelength filtering with orthogonal polarization. Using the electro-optic effect of lithium niobate to change the effective refractive index of the waveguide, fast tuning of two Bragg wavelengths can be achieved. The analysis of the filtering performance of the waveguide grating shows that the etching characteristics of the etching grating are best when the etching gradient is less than 15 ° and the duty cycle is 1/2, and the reflectivity and the bandwidth of the grating increase with the increase of the etching depth . By tuning the waveguide grating with a transverse electric field, the TE mode tuning sensitivity of the dual-wavelength filter reaches 15.6 pm / V and the TM mode achieves 5.5 pm / V.