Sztefka, G.G.SztefkaNolting, H.P.H.P.Nolting2022-03-032022-03-031993https://publica.fraunhofer.de/handle/publica/18388610.1109/68.215279The bidirectional eigenmode propagation (BEP) combines the advantages of the transfer-matrix method for propagation and the mode-matching method (satisfying Maxwell's boundary conditions) at longitudinal large discontinuities for forward and backward travelling eigenvalues including discretized radiation modes. The calculated examples include a grating-assisted codirectional coupler for which 20% radiation losses have been found, and a cleaved waveguide facet with 39% reflected intensity and recapture of radiation modes due to a taperlike structure. The BEP is applicable to various types of optical passive (directional coupler, butt-coupling, taper) and active (DBR-, DFB-, and VCSE-laser, detector) devices with large refractive index differences.endiffraction gratingsdirectional couplerseigenvalues and eigenfunctionsintegrated opticsoptical couplersoptical lossesoptical waveguide theoryrefractive indexforward travelling eigenvalueslaser diodesactive laser devicesphotodetectorsdbr lasersdfb laserslarge refractive index stepsbidirectional eigenmode propagationtransfer-matrix methodmode-matching methodmaxwell's boundary conditionslongitudinal large discontinuitiesbackward travelling eigenvaluesdiscretized radiation modesgrating-assisted codirectional couplerradiation lossescleaved waveguide facetreflected intensitytaperlike structuredirectional couplerbutt-couplingtapervcse-laserlarge refractive index differences621535journal article