title: Low loss coupling to sub-micron thick rib and nanowire waveguides by vertical tapering.
abstract: Highly nonlinear planar glass waveguides have been shown to be useful for all optical signal processing. However, the typical SMF-28 fiber to waveguide coupling loss of ~5dB/end remains a barrier to practical implementation. Low loss coupling to a fiber using vertical tapering of the waveguide film is analyzed for rib and nanowire waveguides and experimentally demonstrated for ribs showing polarization and wavelength independence over >300nm bandwidth. Tapers with essentially zero excess loss led to total losses from the waveguide to fiber core of 1.1dB per facet comprising only material absorption (0.75dB) and mode overlap loss (0.36dB), both of which can be eliminated with improvements to processing and materials.
authors.affiliation: Centre for Ultrahigh Bandwidth Devices for Optical Systems, Laser Physics Centre, Australian National University, Canberra, Australia. sjm111@physics.anu.edu.au
authors.forename: S
authors.initials: S
authors.lastname: Madden
authors.forename: Z
authors.initials: Z
authors.lastname: Jin
authors.forename: D
authors.initials: D
authors.lastname: Choi
authors.forename: S
authors.initials: S
authors.lastname: Debbarma
authors.forename: D
authors.initials: D
authors.lastname: Bulla
authors.forename: B
authors.initials: B
authors.lastname: Luther-Davies
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D008027:Light; D043942:Nanotubes / Q000737:chemistry*; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000295:instrumentation*