TRANSVERSE OFFSET LOSS BETWEEN 2 IDENTICAL NONCIRCULAR SINGLE-MODE WAVE-GUIDES

We derive an approximation for the transverse offset loss based on the Laplacian mode-field half-width (MFHW) and far-field second moment fo r two arbitrary identical noncircular single-mode waveguides. The rela tion is reduced to the known result for circular-symmetric, single-mod e waveguides. Numerical results for symmetrical rectangular waveguides show that the transverse offset loss calculated from the Laplacian MF HW is more accurate than that from the elliptical Gaussian MFHW for sm all transverse offsets. To our knowledge, this is the first calculatio n of the errors in the approximate transverse offset loss relations de rived from the Laplacian and the elliptical Gaussian MFHW for noncircu lar optical waveguides.