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采用微扰法研究了左手介质矩形波导的吸收特性。由于色散方程的限制,左手介质波导不能传输基模,它的吸收特性也与右手介质矩形波导明显不同。结果发现,模式的衰减系数随长宽比(a/b)的增加而减小,而在右手介质波导中结果恰恰相反。除此之外,当不同模式的光波在同一左手介质矩形波导中传输时,每一模式都对应着相邻很近的吸收峰和吸收谷。同时高阶模的衰减系数较低阶模的大。但是,当不同模式的光波在同一右手介质矩形波导中传输时,它们的衰减曲线随着波导宽度的增加而振荡的变化,并且趋近于芯层衰减系数。另外一方面,在右手波导中,高阶模式的衰减系数较低阶模式小。
The perturbation method is used to study the absorption characteristics of rectangular waveguide with left-handed medium. Due to the dispersion equation, the left hand medium waveguide can not transmit the fundamental mode, and its absorption characteristics are also obviously different from that of the right hand medium rectangular waveguide. The results show that the mode attenuation coefficient decreases with increasing aspect ratio (a / b), whereas the right-handed medium waveguide results exactly the opposite. In addition, when different modes of light waves are transmitted in the same left-handed medium rectangular waveguide, each mode corresponds to adjacent absorption peaks and absorption troughs. At the same time, the attenuation coefficient of higher-order mode is lower than the lower-order mode. However, when different modes of light waves are transmitted in the same right-handed medium rectangular waveguide, their attenuation curves oscillate with increasing waveguide width and approach the core attenuation coefficient. On the other hand, in the right-hand waveguide, the higher-order mode has a lower attenuation coefficient than the lower-order mode.