Abstract: Structures including a waveguide core and methods of fabricating a structure including a waveguide core. The structure comprises a substrate, a waveguide core, and a grating disposed in a vertical direction between the waveguide core and the substrate. The grating includes a first plurality of layers and a second plurality of layers that alternate in the vertical direction with the first plurality of layers. The first plurality of layers comprise a first material having a first refractive index, and the second plurality of layers comprise a second material having a second refractive index that is greater than the first refractive index.

Abstract: Structures including a waveguide core and methods of fabricating a structure including a waveguide core. The structure comprises a substrate, a waveguide core, and a grating disposed in a vertical direction between the waveguide core and the substrate. The grating includes a first plurality of layers and a second plurality of layers that alternate in the vertical direction with the first plurality of layers. The first plurality of layers comprise a first material having a first refractive index, and the second plurality of layers comprise a second material having a second refractive index that is greater than the first refractive index.

Abstract: Structures for a wavelength division multiplexing filter and methods of fabricating a structure for a wavelength division multiplexing filter. The structure includes a first waveguide core having a first section and a second section. The first section and the second section have a first notched sidewall and a second notched sidewall opposite to the first notched sidewall. The structure further includes a second waveguide core positioned with a first offset in a first direction relative to the first section and the second section of the first waveguide core and with a second offset in a second direction relative to the first section and the second section of the first waveguide core. The second direction is transverse to the first direction.

Abstract: Structures for a wavelength division multiplexing filter and methods of fabricating a structure for a wavelength division multiplexing filter. The structure includes a first waveguide core having a first section and a second section. The first section and the second section have a first notched sidewall and a second notched sidewall opposite to the first notched sidewall. The structure further includes a second waveguide core positioned with a first offset in a first direction relative to the first section and the second section of the first waveguide core and with a second offset in a second direction relative to the first section and the second section of the first waveguide core. The second direction is transverse to the first direction.

Abstract: Structures for a filter and methods of fabricating a structure for a filter. The filter is coupled to a waveguide core. The filter includes a first plurality of grating structures positioned adjacent to a first section of the waveguide core and a second plurality of grating structures positioned adjacent to a second section of the waveguide core. The first plurality of grating structures are configured to cause laser light in a first portion of a wavelength band to be transferred between the first section of the waveguide core and the first plurality of grating structures. The second plurality of grating structures are configured to cause laser light in a second portion of a wavelength band to be transferred between the second section of the waveguide core and the second plurality of grating structures.