The vast majority of work on waveguide-coupled resonators focuses on decreasing losses in the waveguide and coupling region. Here we present fully integrated resonators based on an ultralow-loss Si3N4 waveguide platform. By tailoring the directional coupler excitation to the resonators, we are able to achieve lower loss singlemode coupling to multimode waveguide widths compared to straight bus ...

We present a device design and fabrication of a novel hollow-waveguide optical switch consisting of a directional coupler with variable air cores. The numerical simulation and experimental characterization of the proposed optical switch performance is discussed. Switching operation is achieved by mode-field change and coupling beat length in the directional coupler section, as the air core thic...

The Substrate Integrated Waveguide (SIW) technology is an attractive approach for the design of high performance microwave and millimeter wave components, as it combines the advantages of planar technology, such as low fabrication costs, with the low loss inherent to the waveguide solution. In this study, a substrate integrated waveguide power divider, circulator and coupler are conceived and o...

We design a compact embedded metallic elliptical focus grating coupler based on gold or silver that efficiently interconnects free space with silicon nitride waveguide at 632.8 nm wavelength. The 3D far-field radiation pattern for the proposed grating coupler shows much higher gain and directivity towards free space coupling than that of the etched grating coupler. Specifically the free space t...

We have characterized low-birefringence, PbF(2) coatings to permit, first, agreement between envelope and prism-coupler waveguide methods under the standard isotropic assumption. In essentially the same measurement conditions, for obliquely deposited (58.3°) CeO(2) coatings the isotropic model becomes unsustainable. Explicit consideration of the film microstructure is then required for good cor...

Diffraction gratings can be used to achieve phase matching between the fundamental modes of a slab or confined waveguide. Compared with the usual techniques such as quasi-, Cerenkov, and intermodal phase matching, the matching method used here involves spatial harmonics of the guided electromagnetic field that are generated by the corrugated grating. This grating acts simultaneously as a linear...

The silicon photonics market has grown rapidly over recent decades due to the demand for high bandwidth and data-transfer capabilities. Silicon leverage well-developed semiconductor fabrication technologies combine various photonic functionalities on same chip. Complicated integrated circuits require a mass-producible packaging strategy with broadband, coupling efficiency, fiber-array fiber-to-...

In this Letter, we propose general optimization methods to design broadband high-efficiency grating couplers for planar waveguides. We attribute the coupling bandwidth to the mismatch of effective indices between the diffracted beam and the actual grating structure around the operation wavelength for fiber to waveguide excitation. The coupling bandwidth formula is deduced. A simple parameter-se...

A porous silicon waveguide with integrated grating coupler is demonstrated as a new platform for portable detection of chemical and biological molecules. The two-layer porous silicon waveguide is formed by electrochemical etching and a photoresist grating is fabricated directly on the waveguide core by means of electron beam lithography. Angle-resolved reflectance measurements reveal distinct p...