P. L. E. Velha

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We design compact (a few wavelength long) and efficient (>99%) injectors for coupling light into slow Bloch modes of periodic thin film stacks and of periodic slab waveguides. The study includes the derivation of closed-form expressions for the injection efficiency as a function of the group-velocity of injected light, and the proof that 100% coupling(More)
A chalcogenide-assisted silicon waveguide is realized by depositing a thin layer of A(2)S(3) glass onto a conventional silicon on insulator optical waveguide. The photosensitivity of the chalcogenide is exploited to locally change the optical properties of the waveguide through exposure to visible light radiation. Waveguide trimming is experimentally(More)
Photonic device structures such as photonic crystals, photonic wires and optical metamaterials - all with submicron features can be described as `nanophotonic'. Many of these devices and structures can be used as sensors. The usual approach is to photonic sensing is to change the refractive index of a surrounding medium. Here we consider several(More)
Nanobeam cavities based on Silicon-On-Insulator (SOI) working at telecommunication wavelengths (1550 nm) provide an ideal platform to use for label free sensing due to their features of high Qs, high sensitivity and capability for CMOS integration. We present some recent results showing the design modeling, fabrication, and experimental measurement of(More)
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