Composite optical fibre–slab waveguides: a scalar,coupled-mode analysis with vector corrections

Analytically-derived vector corrections are included as additional coupling coefficients in numerical calculations of scalar coupled-mode and compound-mode theory (SCMT) of composite fibre–slab waveguides. The slab waveguide is asymmetric, with moderate light-wave guiding and coupling assumed and the resultant polarization effects are of interest. It is found that the modifications to light propagation and coupling coefficients determined previously by first-order SCMT are dependent mainly on the strength of coupled fibre and slab modes, the thickness of the guiding layers and the ratio of refractive indices of guiding to cladding layer (asymmetry of the slab waveguide). The vector corrections observed are not significant compared with our previous SCMT results, as the optical constants defined appear to satisfy the approximations necessary for the scalar analysis. This revised version was published online in June 2006 with corrections to the Cover Date.