Abstract: This disclosure relates to the layout of optical components included in a photonics integrated circuit (PIC) and the routing of optical traces between the optical components. The optical components can include light sources, a detector array, and a combiner. The optical components can be located in different regions of a substrate of the PIC, where the regions may include one or more types of active optical components, but also may exclude other types of active optical components. The optical traces can include a first plurality of optical traces for routing signals between light sources and a detector array, where the first plurality of optical traces can be located in an outer region of the substrate. The optical traces can also include a second plurality of optical traces for routing signals between the light sources and a combiner, where the second plurality of optical traces can be located in regions between banks of the light sources.

Abstract: A photonic integrated circuit including multiple elements formed by different processes onto separate chips can be manufactured by defining, via photolithography processes for example, complementary geometries onto each separate chip. Thereafter, the complementary geometries can be aligned and engaged, thereby optically and mechanically intercoupling the several chips to define a single photonic integrated circuit.

Abstract: A multi-chip photonic assembly includes first and second photonic integrated circuits having first and second waveguides vertically stacked such that first vertical dimensions of the first and second waveguides occupy different horizontal planes in the stack. At least one of the first and second waveguides has a region that has a second vertical dimension that is larger than the first vertical dimension and either horizontally overlaps the other waveguide and/or vertically contacts the other waveguide. Light moving through one of the waveguides from the first vertical dimension to the other vertical dimension changes modes vertically so that the light moves from one waveguide to the other.

Abstract: Configurations for an optical system used for guiding light and reducing back-reflection back in an output waveguide is disclosed. The optical system may include an output waveguide defined in a slab waveguide. The output waveguide may terminate before an output side of the slab waveguide, which may reduce the back-reflection of light from the output side back into the output waveguide. The output side may define an optical element that may steer the output light. The optical element may collimate the output light, cause the output light to converge, or cause the output light to diverge.

Abstract: Configurations for an optical system used for guiding light and reducing back-reflection back in an output waveguide is disclosed. The optical system may include an output waveguide defined in a slab waveguide. The output waveguide may terminate before an output side of the slab waveguide, which may reduce the back-reflection of light from the output side back into the output waveguide. The output side may define an optical element that may steer the output light. The optical element may collimate the output light, cause the output light to converge, or cause the output light to diverge.

Abstract: An electronic device may include wireless circuitry clocked using an electro-optical phase-locked loop (OPLL) having primary and secondary lasers. A frequency-locked loop (FLL) path and a phase-locked loop (PLL) path may couple an output of the secondary laser to its input. A photodiode may generate a photodiode signal based on the laser output. A digital-to-time converter (DTC) may generate a reference signal. The FLL path may coarsely tune the secondary laser based on the photodiode signal until the secondary laser is frequency locked. Then, the PLL path may finely tune the secondary laser based on the reference signal and the photodiode signal until the phase of the secondary laser is locked to the primary laser. The photodiode signal may be subsampled on the PLL path. This may allow the OPLL to generate optical local oscillator signals with minimal jitter and phase noise.

Abstract: A waveguide structure and a method for splitting light is described. The method may include optically coupling a first waveguide and a second waveguide, where the optical coupling may be wavelength insensitive. The widths of the first and second waveguides may be non-adiabatically varying and the optical coupling may be asymmetric between the first and second waveguides. A gap between the first and second waveguides may also be varied non-adiabatically and the gap may depend on the widths of the first and second waveguides. The optical coupling between the first and second waveguides may also occur in the approximate wavelength range of 800 nanometers to 1700 nanometers.

Abstract: Configurations for a tunable Echelle grating are disclosed. The tunable Echelle grating may include an output waveguide centered in a waveguide array, with input waveguides on both sides of the output waveguide. A metal tuning pad may be located over the slab waveguide and may be heated to induce a temperature change in the slab waveguide. By increasing the temperature of the propagation region of the slab waveguide, the index of refraction may shift, thus causing the peak wavelength of the channel to shift. This may result in an optical component capable of multiplexing multiple light sources in an energy efficient manner while maintaining a small form factor.

Abstract: This disclosure relates to the layout of optical components included in a photonics integrated circuit (PIC) and the routing of optical traces between the optical components. The optical components can include light sources, a detector array, and a combiner. The optical components can be located in different regions of a substrate of the PIC, where the regions may include one or more types of active optical components, but also may exclude other types of active optical components. The optical traces can include a first plurality of optical traces for routing signals between light sources and a detector array, where the first plurality of optical traces can be located in an outer region of the substrate. The optical traces can also include a second plurality of optical traces for routing signals between the light sources and a combiner, where the second plurality of optical traces can be located in regions between banks of the light sources.

Abstract: Configurations for a diffraction grating design and methods thereof are disclosed. The diffraction grating system can include an input waveguide located at a first location on or near a Rowland circle and multiple output waveguides located at a second and third location on or near the Rowland circle. The input waveguide may be located between the output waveguides and this configuration of input and output waveguides can reduce the footprint size of the device. In some examples, the optical component can function as a de-multiplexer. Additionally, the optical component may separate the input wavelength band into two output wavelength bands which are separated from one another by approximately 0.1 ?m.

Abstract: A waveguide structure and a method for splitting light is described. The method may include optically coupling a first waveguide and a second waveguide, where the optical coupling may be wavelength insensitive. The widths of the first and second waveguides may be non-adiabatically varying and the optical coupling may be asymmetric between the first and second waveguides. A gap between the first and second waveguides may also be varied non-adiabatically and the gap may depend on the widths of the first and second waveguides. The optical coupling between the first and second waveguides may also occur in the approximate wavelength range of 800 nanometers to 1700 nanometers.

Abstract: Methods for driving a tunable laser with integrated tuning elements are disclosed. The methods can include modulating the tuning current and laser injection current such that the laser emission wavelength and output power are independently controllable. In some examples, the tuning current and laser injection current are modulated simultaneously and a wider tuning range can result. In some examples, one or both of these currents is sinusoidally modulated. In some examples, a constant output power can be achieved while tuning the emission wavelength. In some examples, the output power and tuning can follow a linear relationship. In some examples, injection current and tuning element drive waveforms necessary to achieve targeted output power and tuning waveforms can be achieved through optimization based on goodness of fit values between the targeted and actual output power and tuning waveforms.

Abstract: Disclosed is a Vernier effect DBR laser that has uniform laser injection current pumping along the length of the laser. The laser can include one or more tuning elements, separate from the laser injection element, and these tuning elements can be used to control the temperature or modal refractive index of one or more sections of the laser. The refractive indices of each diffraction grating can be directly controlled by temperature changes, electro optic effects, or other means through the one or more tuning elements. With direct control of the temperature and/or refractive indices of the diffraction gratings, the uniformly pumped Vernier effect DBR laser can be capable of a wider tuning range. Additionally, uniform pumping of the laser through a single electrode can reduce or eliminate interfacial reflections caused by, for example, gaps between metal contacts atop the laser ridge, which can minimize multi-mode operation and mode hopping.

Abstract: A cantilever beam waveguide for a silicon photonics device may be formed in a device layer (e.g., a silicon device layer) of a silicon photonics device (e.g., a chip) and may be configured to bend to align the cantilever beam waveguide or a portion thereof with one or more additional components of the silicon photonics device or another device, including output couplers, optical sources, and waveguides.

Abstract: Methods and systems concerning demultiplexing and multiplexing light in optical multiplexing systems are disclosed herein. An optical multiplexing system may include a number of light emitters and a number of associated waveguides. Light emitted from each of the number of light emitters may travel through the associated waveguide and may enter a multiplexer, where a multiplexing operation may occur. At least one of the number of light emitters may be configured to emit light with multiple wavelengths. Such a light emitter may further be associated with a demultiplexer to demultiplex the light with multiple wavelengths before the light reaches a multiplexer. After a demultiplexing operation, the demultiplexed light may be directed to multiple waveguides and the multiple waveguides may guide the demultiplexed light to a multiplexer.

Abstract: Configurations for an optical system with phase shifting elements are disclosed. The optical system may include a first waveguide that provides light to a second waveguide, which may be a slab waveguide. A phase shifting element may be disposed on the slab waveguide and may be heated to induce a temperature change in the slab waveguide. By increasing the temperature of the propagation region of the slab waveguide, the index of refraction of the propagation region of the slab waveguide may shift, thus causing the index of refraction of light propagating through the propagation region to shift, thus shifting the phase of the light. This may result in an optical component capable of phase shifting light for reducing coherent noise while being energy efficient and maintaining a small form factor.

Abstract: Configurations for a tunable Echelle grating are disclosed. The tunable Echelle grating may include an output waveguide centered in a waveguide array, with input waveguides on both sides of the output waveguide. A metal tuning pad may be located over the slab waveguide and may be heated to induce a temperature change in the slab waveguide. By increasing the temperature of the propagation region of the slab waveguide, the index of refraction may shift, thus causing the peak wavelength of the channel to shift. This may result in an optical component capable of multiplexing multiple light sources in an energy efficient manner while maintaining a small form factor.

Abstract: Configurations for an edge-generated vertical emission laser that vertically emits light and fabrication methods of the edge-generated vertical emission laser are disclosed. The edge-generated vertical emission laser may include a distributed feedback (DFB) laser structure, a grating coupler, and contact layers. Light may propagate through the DFB laser structure, approximately parallel to the top surface of the edge-generated vertical emission laser and be directed by the grating coupler toward the top surface of the edge-generated vertical emission laser. The light may vertically emit from the edge-generated vertical emission laser approximately perpendicular to the top surface of the edge-generated vertical emission laser. Additionally, the contact layers may be n-metal and p-metal, which may be located on the same side of the edge-generated vertical emission laser. These features of the edge-generated vertical emission laser may facilitate ease of testing and increased options for packaging.

Abstract: Configurations for a diffraction grating design that mitigates thermal wavelength shifts and corresponding methods thereof are disclosed. The wavelength stability monitoring system may include a planar waveguide that receives input light directed toward a diffraction grating. The diffraction grating may reflect the light back through the planar waveguide and to one or more detectors. The planar waveguide may include multiple materials, such as a first material and a second athermal material that is adjacent to the first material. The athermal material may mitigate thermal wavelength shifts of the light. The design of the athermal material may include targeting a ratio of the input and output path lengths across sets of input and output angles of light that pass through the first material and the second athermal material. In some examples, the output waveguides may be positioned to receive leakage modes of light.

Abstract: A device including a plurality of epitaxial chips is disclosed. An epitaxial chip can have one or more of a light source and a detector, where the detector can be configured to measure the optical properties of the light emitted by a light source. In some examples, one or more epitaxial chips can have one or more optical properties that differ from other epitaxial chips. The epitaxial chips can be dependently operable. For example, the detector located on one epitaxial chip can be configured for measuring the optical properties of light emitted by a light source located on another epitaxial chip by way of one or more optical signals. The collection of epitaxial chips can also allow detection of a plurality of laser outputs, where two or more epitaxial chips can have different material and/or optical properties.