In terms of coupled-mode theory, only two real-valued normalized parameters are needed for describing the spectral properties of any 1D photonic crystal of finite size made of lossless materials: detuning (δL) with respect to the Bragg condition and coupling strength (κL). As far as its quasi-normal mode (QNM) spectrum is concerned, the usual “complex frequency” concept can be replaced by an effective “complex detuning” (δL + i αL), thus establishing a formal connection with the modal cartography, in the (κL, αL) plane, of purely index-coupled distributed-feedback lasers of normalized gain αL.

中文翻译：

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一维光子晶体中准正常模式的通用耦合模式理论公式

在耦合模式理论方面，描述任何由无损材料制成的有限尺寸一维光子晶体的光谱特性只需要两个实值归一化参数：关于布拉格条件和耦合强度 (κL) 的失谐 (δL) ）。就其准正态模（QNM）谱而言，通常的“复频率”概念可以被有效的“复失谐”（δL + i αL）代替，从而与模态制图建立正式联系，在(κL, αL) 平面，纯指数耦合分布式反馈激光器的归一化增益 αL。