Details of the implemented formalisms for scalar and vectorial bidirectional and quadridirectional eigenmode expansion:

M. Hammer
Oblique incidence of semi-guided waves on rectangular slab waveguide discontinuities: A vectorial QUEP solver
Optics Communications 338, 447-456 (2015)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer
Quadridirectional eigenmode expansion scheme for 2-D modeling of wave propagation in integrated optics
Optics Communications 235 (4-6), 285-303 (2004)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Lohmeyer
Mode expansion modeling of rectangular integrated optical microresonators
Optical and Quantum Electronics 34 (5), 541-557 (2002)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Lohmeyer, R. Stoffer
Integrated optical cross strip polarizer concept
Optical and Quantum Electronics 33 (4/5), 413-431 (2001)  Preprint (ps.gz)  Preprint (pdf)  External online source

About the hybrid variant of coupled mode theory:

M. Hammer
Hybrid analytical/numerical coupled-mode modeling of guided wave devices
Journal of Lightwave Technology 25 (9), 2287-2298 (2007)  Preprint (ps.gz)  Preprint (pdf)  External online source

On the variational approach for 2-to-1D effective index reduction:

M. Hammer, O.V. Ivanova
Effective index approximations of photonic crystal slabs: a 2-to-1-D assessment
Optical and Quantum Electronics 41 (4), 267-283 (2009)  Preprint (ps.gz)  Preprint (pdf)  External online source

Details of the VEIMS mode solver for 3D channels:

O.V. Ivanova, R. Stoffer, M. Hammer
A variational mode solver for optical waveguides based on quasi-analytical vectorial slab mode expansion
University of Twente, technical report, 19 pages (2009)  Preprint (ps.gz)  Preprint (pdf)
arXiv:1307.1315 [physics.optics]   External online source

On bend modes and whispering gallery resonances:

E.F. Franchimon, K.R. Hiremath, R. Stoffer, M. Hammer
Interaction of whispering gallery modes in integrated optical micro-ring or -disk circuits: Hybrid CMT model
Journal of the Optical Society of America B 30 (4), 1048-1057 (2013)  Preprint (ps.gz)  Preprint (pdf)  External online source

K.R. Hiremath, M. Hammer, R. Stoffer, L. Prkna, J. Ctyroky
Analytical approach to dielectric optical bent slab waveguides
Optical and Quantum Electronics 37 (1-3), 37-61 (2005)  Preprint (ps.gz)  Preprint (pdf)  External online source

Further numerical experiments & theoretical results based (partly) on these tools:

M. Hammer, L. Ebers, J. Förstner
Configurable lossless broadband beam splitters for semi-guided waves in integrated silicon photonics
OSA Continuum 4 (12), 3081-3095 (2021)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer, L. Ebers, J. Förstner
Resonant evanescent excitation of guided waves with high-order optical angular momentum
Journal of the Optical Society of America B 38 (5), 1717-1728 (2021)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer, L. Ebers, J. Förstner
Hybrid coupled mode modelling of the evanescent excitation of a dielectric tube by semi-guided waves at oblique angles
Optical and Quantum Electronics 52, 472 (2020)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer, L. Ebers, J. Förstner
Oblique quasi-lossless excitation of a thin silicon slab waveguide: A guided-wave-variant of an anti-reflection coating
Journal of the Optical Society of America B 36 (9), 2395-2401 (2019)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer, L. Ebers, J. Förstner
Oblique evanescent excitation of a dielectric strip: A model resonator with an open optical cavity of unlimited Q
Optics Express 27 (7), 9313-9320 (2019)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer, Andre Hildebrandt, Jens Förstner
How planar optical waves can be made to climb dielectric steps
Optics Letters 40 (16), 3711-3714 (2015)  Preprint (pdf)  External online source

F. Civitci, M. Hammer, H.J.W.M. Hoekstra
Semi-guided plane wave reflection by thin-film transitions for angled incidence
Optical and Quantum Electronics 46 (3), 477-490 (2014)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer
HCMT models of optical microring-resonator circuits
Jounal of the Optical Society of America B 27 (11), 2237-2246 (2010)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer
Chains of coupled square dielectric optical microcavities
Optical and Quantum Electronics 40 (11-12), 821-835 (2009)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer, R. Stoffer
PSTM / NSOM modeling by 2-D quadridirectional eigenmode expansion
Journal of Lightwave Technology 23 (5), 1956-1966 (2005)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer, D. Yudistira, R. Stoffer
Modeling of grating assisted standing wave microresonators for filter applications in integrated optics
Optical and Quantum Electronics 36 (1-3), 25-42 (2004)  Preprint (ps.gz)  Preprint (pdf)  External online source

E. Flück, M. Hammer, A. M. Otter, J. P. Korterijk, L. Kuipers, N. F. van Hulst
Amplitude and phase evolution of optical fields inside periodic photonic structures
Journal of Lightwave Technology 21 (5), 1384-1393 (2003)  External online source

M. Hammer
Resonant coupling of dielectric optical waveguides via rectangular microcavities: The coupled guided mode perspective
Optics Communications 214 (1-6), 155-170 (2002)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Hammer, E. van Groesen
Total multimode reflection at facets of planar high contrast optical waveguides
Journal of Lightwave Technology 20 (8), 1549-1555 (2002)  Preprint (ps.gz)  Preprint (pdf)  External online source

M. Lohmeyer, L. Wilkens, O. Zhuromskyy, H.Dötsch, P. Hertel
Integrated magnetooptic cross strip isolator
Optics Communications 189 (4-6), 251-259 (2001)  Preprint (ps.gz)  Preprint (pdf)  External online source