We introduce a theoretical formalism to describe disorder-induced extrinsic scattering inslow light photonic crystal waveguides. This work details and extends the optical scatteringtheory used in a recent issue of Physics Review Letters (Patterson et al 2009 Phys. Rev.Lett. 102 253903) to describe coherent scattering phenomena and successfully explainrelated experimental measurements. Our presented theory, which combines Green functionand coupled mode methods, allows us to self-consistently account for arbitrary multiplescattering for the propagating electric field and recover experimental features such asresonances near the band edge. The technique is fully three-dimensional and can calculatethe effects of disorder on the propagating field over thousands of unit cells. As anapplication of this theory, we explore various sample lengths and disordered instances, anddemonstrate the profound effect of multiple scattering in the waveguide transmission.The spectra yield rich features associated with disorder-induced localization andmultiple scattering, which are shown to be exacerbated in the slow light propagationregime.
Read full abstract