摘要
基于钛扩散铌酸锂(Ti∶LiNbO3)波导的集成光学电光调制技术的干涉光谱仪是Ti∶LiNbO3调制器的一种崭新应用,一般应用的探测光谱区间是在波导的单模区间。为拓宽探测波长范围至多模传输范围,以x向切割,y向传输。以共面对称电极的Ti∶LiNbO3波导电光调制干涉器(器件长度60mm)为例,模拟了多模传输时电光调制系数的模式色散现象。数值模拟中采用了有限差分方法(FDM)。分析表明,在多模传输情况下,光的各阶模式的光场分布差异导致了电光调制系数的模式色散;在对经线性扫描电压调制后的干涉输出数据进行傅里叶变换谱分析后,可发现对应波长的各阶传输模式谱。实验采用0.808μm单模偏振光源,在激励起准TE多模式和激励起混合模两种情况下,验证了数值模拟和分析的结果。
The electro-optic modulation coefficient mode dispersion phenomenon in a 60mm long Ti ： LiNbO3 waveguide Mach-Zehnder modulator with symmetric complementary coplanar electrodes is analyzed. The finite difference method is used in the simulation. A series of experiments are carried out to verify the analyses. Simulation suggests that the electro-optic modulation coefficient mode dispersion is dependent on the mode profiles. The differences of the mode profiles cause the electro-optic modulation coefficient dispersion. By coupling in with 808nm laser source, simultaneously modulated by linearly varying voltage, after Fourier transforming the recorded interference fringes, one can clearly see the modes in the spectrum. This analysis method might be useful in expanding the working bandwidth of an integrated optical interference spectrometer.
出处
《光学技术》
CAS
CSCD
北大核心
2012年第4期488-492,共5页
Optical Technique
基金
国家自然科学基金资助项目(60978042
61078039)
关键词
光谱学
集成光学
电光调制系数
模式色散
钛扩散铌酸锂
有限差分法
spectroscopy
integrated optics
electro-optic modulation
mode dispersion
Ti ： LiNbO3
finite difference method
