A grating based optical transmitter includes a light source region coupled to an interference region, two reflective regions on both sides of the interference region, and one or several gratings interacting with the interference light wave in the interference region causing a vertical emission. Two electrodes are used to inject electrical carriers, and a third electrode can be added to modulate the electrical carrier density recombined in the light source region. Compared to conventional edge-emitting laser with two electrodes, the grating-based optical transmitter in this invention largely reduces the packaging cost and complexity due to the vertical emission, and largely enhances the modulation bandwidth due to the three-terminal configuration.

An optical waveguide structure. In some embodiments, the optical waveguide structure includes a semiconductor waveguide having a waveguide ridge, and a heater. The waveguide ridge may have a varying dopant concentration across its cross-section. The heater may include a first contact and a second contact, and the waveguide structure may include a conductive path from the first contact to the second contact, the conductive path extending through a doped portion of the waveguide ridge.

An optical waveguide structure. In some embodiments, the optical waveguide structure includes a semiconductor waveguide having a waveguide ridge, and a heater. The waveguide ridge may have a varying dopant concentration across its cross-section. The heater may include a first contact and a second contact, and the waveguide structure may include a conductive path from the first contact to the second contact, the conductive path extending through a doped portion of the waveguide ridge.

A method includes: determining a first material and a second material of a photonic waveguide for propagating light, the photonic waveguide having a first section and a second section arranged in a first layer and a second layer, respectively, of the photonic waveguide; determining a spacing between the first layer and the second layer; determining a parameter set of a crosstalk reduction structure, according to the spacing, the first material and a wavelength of the light, to cause insertion losses of the first section and the second section to be lower than a predetermined threshold; and forming the first and second sections with the first and second materials, respectively, the first section having the crosstalk reduction structure overlapping the second section.

A method includes: determining a first material and a second material of a photonic waveguide for propagating light, the photonic waveguide having a first section and a second section arranged in a first layer and a second layer, respectively, of the photonic waveguide; determining a spacing between the first layer and the second layer; determining a parameter set of a crosstalk reduction structure, according to the spacing, the first material and a wavelength of the light, to cause insertion losses of the first section and the second section to be lower than a predetermined threshold; and forming the first and second sections with the first and second materials, respectively, the first section having the crosstalk reduction structure overlapping the second section.

An electronic device may include a display that generates light for an optical system that redirects the light towards an eye box. The optical system may include a waveguide, a non-diffractive input coupler, a cross coupler, and an output coupler. The cross coupler may expand the light in a first direction. The cross coupler may perform an even number of diffractions on the light and may couple the light back into the waveguide at an angle suitable for total internal reflection. The output coupler may expand the light in a second direction while coupling the light out of the waveguide. The cross coupler may include surface relief gratings or holographic gratings embedded within the waveguide or formed in a separate substrate. The optical system may direct the light towards the eye box without chromatic dispersion and while supporting an expanded field of view and optical bandwidth.

An electronic device may include a display that generates light for an optical system that redirects the light towards an eye box. The optical system may include a waveguide, a non-diffractive input coupler, a cross coupler, and an output coupler. The cross coupler may expand the light in a first direction. The cross coupler may perform an even number of diffractions on the light and may couple the light back into the waveguide at an angle suitable for total internal reflection. The output coupler may expand the light in a second direction while coupling the light out of the waveguide. The cross coupler may include surface relief gratings or holographic gratings embedded within the waveguide or formed in a separate substrate. The optical system may direct the light towards the eye box without chromatic dispersion and while supporting an expanded field of view and optical bandwidth.

An optical bandsplitter (100) comprising: a substrate structure (102), a first waveguide (110) and a second waveguide (130). The first waveguide (110) comprising a first end section (112), a second end section (114) and a first grating section (116) between the first and second end sections. The second waveguide (130) provided adjacent at least one surface of the first waveguide. The first grating section comprising a first grating structure having a grating period, ?, configured to cause the first grating structure to couple light (152) at wavelengths within a spectral range between the first grating section and the second waveguide.

An optical bandsplitter (100) comprising: a substrate structure (102), a first waveguide (110) and a second waveguide (130). The first waveguide (110) comprising a first end section (112), a second end section (114) and a first grating section (116) between the first and second end sections. The second waveguide (130) provided adjacent at least one surface of the first waveguide. The first grating section comprising a first grating structure having a grating period, ?, configured to cause the first grating structure to couple light (152) at wavelengths within a spectral range between the first grating section and the second waveguide.

A photonic chip for scene illumination, the photonic chip comprises a substrate comprising a face with an etching, a plurality of waveguides extending parallel to a plane formed by the etched face of the substrate, each waveguide being configured to guide at least one light beam, a plurality of diffraction gratings, respectively formed in a waveguide and each being configured to extract, out of the waveguide in which it is formed and towards the etching of the substrate, the light beam propagating in said waveguide, at least two waveguides being configured to receive light beams of different wavelengths, and wherein the etching of the substrate is configured to extract the light beams out of the substrate, towards the scene to be illuminated, said scene lying against the etched face of the substrate and at the level of the etching of the substrate.