偏振无关的双折射多波长滤波器的Z域设计

基于双折射铌酸锂晶体的电光效应,设计了一种偏振无关的二端口波导型多波长可调谐滤波器.在非对称干涉仪的上下分支波导上,耦合电极与相移电极周期性交叉级联实现模式的偏振转换.利用琼斯矩阵的Z域分析,求解驱动电压模拟实现多个波长的同时选择.仿真实现了自由光谱范围内分布任意的窄带多波长输出.波长中心处传输率为100%;旁瓣大小受到所选波长个数的影响,三个波长同时滤波的旁瓣可达12 dB.同时得到了梳状滤波输出谱,其通带顶部平坦,旁瓣可达15 dB以上.

Z-domain Design of Polarization-independent Birefringent Multi-wavelength Filter

A polarization-independent two-port wave-guided multi-wavelength tunable fiter is designed based on the electro-optic effect of birefringent Lithium Niobate (LiNbO₃) crystal. Mode-coupled electrode and phase-shifted electrode periodically alternated cascaded are set on each arm of an asymmetric interferometer to realize mode conversion. Z-domain analysis of Jones matrix is utilized to get the values of driving voltages so that wavelengths can be selected simultaneous. Narrow-band multi-wavelength with arbitrary distribution is simulated successfully in Free Spectrum Range (FSR). 100% transmittance is obtained at each wavelength. Number of wavlengths has an influence on sidelobe of each wavelength. And sidelobe of 12 dB can be realized when three wavelengths are selected. Comb filter can also be obtained using this method, which has a flat passband and sidelobe of more than 15 dB.