Universal coupled-mode theory formulation of quasi-normal modes in a 1D photonic crystal.

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. [ABSTRACT FROM AUTHOR]