通信波段金属包覆波导传播特性研究

Propagation properties of metal clad waveguide at communication frequency

采用等效折射率的方法,以金、银、铜作为金属材料,计算了入射波长为1550nm时,2种不同结构金属包覆波导的几何色散关系、场分布特征及损耗情况。采用金属为衬底的非对称包覆结构进行计算,结果表明TE模的特点与全介质波导的情况类似。采用双面金属对称包覆结构进行计算,计算表明TM0模由金属-介质界面处的表面模对称结合而成,其等效折射率不在导模的范围之中,TE模和TM1模等效折射率的范围大于全介质波导的情况,TM1模由金属-介质界面处的表面模反对称结合而成。

Dispersion properties,field distribution and propagation loss of symmetric and asymmetric metal clad waveguide at 1500nm were analyzed with effective index method. Simulation was given for Au,Ag and Cu cladding. In asymmetric clad guide simulation,properties of TE modes are the same as those of dielectric waveguide,TM0 mode is the surface mode at metal-dielectric interface with no cut-off. In symmetric clad guide simulation,TM0 mode is even mode which is coupling between surface modes at two metal-dielectric interface,and its effective index is beyond the index range of guide modes. The range of the effective index of TE mode and TM1 mode is larger than guide modes and TM1 mode is odd mode which is coupling between surface modes at two metal-dielectric interface.