A light detection and ranging (LiDAR) system according to the present disclosure comprises an optical source to emit an optical beam. The LiDAR system comprises a PSR comprising a silicon nitride based waveguide to split and rotate a target return signal of the optical beam from a target. The silicon nitride based waveguide includes a first silicon nitride segment and a second silicon nitride segment. The first silicon nitride segment includes a first layer and a second layer. The first silicon nitride segment has tapered widths along a longitudinal direction. The second silicon nitride segment includes a silicon nitride adiabatic coupler. The LiDAR system further comprises an optical element to generate a local oscillator (LO) signal and a PD to mix the target return signal with the LO signal to generate a heterodyne signal to extract information of the target.

Disclosed herein are methods, structures, and devices for wafer scale testing of photonic integrated circuits.

The present invention concerns an optical coupling device including at least one supporting layer comprising a first support wall and a second support wall. The at least one supporting layer comprises at least one bridging waveguide for coupling electromagnetic radiation to and from an optical resonator or optical device, the at least one bridging waveguide extending between the first support wall and the second support wall.

A semiconductor light-emitting device includes an active layer including quantum dots, a diffraction grating, a low-reflectance film disposed at a light-emitting end of the active layer, and a high-reflectance film disposed at another end of the active layer and having an optical reflectance higher than an optical reflectance of the low-reflectance film.

A photonic device can include an optical detector (e.g., a photodetector) coupled to silicon waveguides. Unlike silicon, germanium is an efficient detector at the wavelength of optical signals typically used for data communication. Instead of directly coupling the waveguide to the germanium, in one embodiment, the waveguide extends below the germanium but is spaced sufficiently away from the germanium so that the optical signal is not transferred. Instead, an optical transfer structure (e.g., a tapered waveguide or an optical grating) is disposed between the germanium and the waveguide. The waveguide first transfers the optical signal into the optical transfer structure which then transfers the optical signal into the germanium.

A waveguide coupling structure includes: a first section that supports a mode that has an associated first intensity profile that substantially overlaps with an intensity profile associated with a mode supported by a first waveguide portion at a first end of the waveguide coupling structure; a second section that supports a mode that has an associated second intensity profile that substantially overlaps with an intensity profile associated with a mode supported by a second waveguide portion at a second end of the waveguide coupling structure; and a third section, between the first section and the second section, comprising a core structure on a bottom cladding and a supporting structure on the bottom cladding. The supporting structure: (1) overlaps with at least a portion of an intensity profile associated with a guided mode of the third section, and (2) has a shape that is asymmetric with respect to a propagation axis of the guided mode in a plane parallel to a surface of the bottom cladding.

A LiDAR system includes an optical source to emit an optical beam and a PSR a silicon nitride based waveguide to split and rotate an optical beam. The silicon nitride based waveguide includes a first silicon nitride segment including a first layer and a second layer, the first silicon nitride segment having tapered widths along a longitudinal direction. The second layer includes a first section extending from a first end of the first silicon nitride segment to a converging plane with increasing widths and a second section extending from the converging plane to a second end of the first silicon nitride segment with decreasing widths. The LIDAR system further includes an optical element to generate a local oscillator (LO) signal and an optical detector to mix the target return signal with the LO signal to generate a heterodyne signal to extract range and velocity information of the target.

A device, such as an electroabsorption modulator, can modulate a light intensity by controllably absorbing a selectable fraction of the light. The device can include a substrate. A waveguide positioned on the substrate can guide light. An active region positioned on the waveguide can receive guided light from the waveguide, absorb a fraction of the received light, and return a complementary fraction of the received light to the waveguide. Such absorption produces heat, mostly at an input portion of the active region. The input portion of the active region can be thermally coupled to the substrate, which can dissipate heat from the input portion, and can help avoid thermal runaway of the device. The active region can be thermally isolated from the substrate away from the input portion, which can maintain a relatively low thermal mass for the active region, and can increase efficiency when heating the active region.

A spot size converter includes a first waveguide including a first core layer, the first waveguide propagating light; and a second waveguide including a second core layer and provided on the first waveguide, the second waveguide propagating light. The first waveguide and the second waveguide extend in a waveguide direction. A first region and a second region are provided continuously along the waveguide direction. In the first region, the second waveguide has a tapered shape in a cross section which becomes narrower as going up away from the first waveguide. An angle between a side surface of the second waveguide and a bottom surface of the second waveguide is 60 or less.

A waveguide coupling structure includes: a first section that supports a mode that has an associated first intensity profile that substantially overlaps with an intensity profile associated with a mode supported by a first waveguide portion at a first end of the waveguide coupling structure; a second section that supports a mode that has an associated second intensity profile that substantially overlaps with an intensity profile associated with a mode supported by a second waveguide portion at a second end of the waveguide coupling structure; and a third section, between the first section and the second section, comprising a core structure on a bottom cladding and a supporting structure on the bottom cladding. The supporting structure: (1) overlaps with at least a portion of an intensity profile associated with a guided mode of the third section, and (2) has a shape that is asymmetric with respect to a propagation axis of the guided mode in a plane parallel to a surface of the bottom cladding.