Abstract: An integrated circuit that includes a wavelength-filter layer stack (which may include silicon oxynitride) and an optical substrate (such as a silicon-on-insulator platform) is described. During operation, an optical signal received from an optical fiber or an optical waveguide is wavelength filtered into a set of wavelength-filter optical waveguides by an optical multiplexer/demultiplexer (such as an Echelle grating and/or an array waveguide grating) in the wavelength-filter layer stack. Then, wavelength-filtered optical signals are optically coupled to the optical substrate, where they are received using photodetectors. Alternatively, modulators in the optical substrate modulate wavelength-filtered modulated optical signals, which are then optically coupled to the set of wavelength-filter optical waveguides in the wavelength-filter layer stack.

Abstract: An optical transmitter includes a reflective semiconductor optical amplifier (RSOA) coupled to an input end of a first optical waveguide. An end of the first optical waveguide provides a transmitter output for the optical transmitter. Moreover, a section of the first optical waveguide between the input end and the output end is optically coupled to a ring modulator that modulates an optical signal based on an electrical input signal. A passive ring filter (or a 1×N silicon-photonic switch and a bank of band reflectors) is connected to provide a mirror that reflects light received from the second optical waveguide back toward the RSOA to form a lasing cavity. Moreover, the ring modulator and the passive ring filter have different sizes, which causes a Vernier effect that provides a large wavelength tuning range for the lasing cavity in response to tuning the ring modulator and the passive ring filter.

Abstract: Technologies relating to determining data variable dependencies to facilitate code execution are disclosed. An example method includes: identifying a set of programming statements having a plurality of data parameters; identifying first data parameters associated with a first programming statement in the set of programming statements; determining one or more parameter dependencies associated with the first data parameters; and determining, based on the one or more parameter dependencies, a first execution performance of the first programming statement. The method may further include: determining a second execution performance of the second programming statement and scheduling execution of the first programming statement and of the second programming statement based on the first and second execution performances.

Abstract: Methods and systems to identify computer system nodes to which a computer program thread is to be migrated. An example method disclosed herein includes storing data records containing node identifying information collected from a plurality of sampled memory operations executed by a plurality of computer program threads including a first computer program thread. Example methods further include identifying a currently executing computer program thread and, if the currently executing computer program thread is the first computer program thread, target remote nodes having a memory address accessed during execution of at least one of the plurality of sampled memory operations are identified. At least one of the target remote nodes is selected as a migration destination candidate for the first computer program thread.

Abstract: An integrated circuit that includes a wavelength-filter layer stack (which may include silicon oxynitride) and an optical substrate (such as a silicon-on-insulator platform) is described. During operation, an optical signal received from an optical fiber or an optical waveguide is wavelength filtered into a set of wavelength-filter optical waveguides by an optical multiplexer/demultiplexer (such as an Echelle grating and/or an array waveguide grating) in the wavelength-filter layer stack. Then, wavelength-filtered optical signals are optically coupled to the optical substrate, where they are received using photodetectors. Alternatively, modulators in the optical substrate modulate wavelength-filtered modulated optical signals, which are then optically coupled to the set of wavelength-filter optical waveguides in the wavelength-filter layer stack.

Abstract: A hybrid optical source comprises an optical gain chip containing an optical gain material that provides an optical signal, and an optical reflector chip including an optical reflector. It also includes a semiconductor-on-insulator (SOI) chip, which comprises a semiconductor layer having a planarized surface facing the semiconductor reflector. The semiconductor layer includes: an optical coupler to redirect the optical signal to and from the planarized surface; and an optical waveguide to convey the optical signal from the optical coupler. While assembling these chips, a height of the optical gain material is referenced against the planarized surface of the semiconductor layer, a height of the optical reflector is referenced against the planarized surface of the semiconductor layer, and the optical reflector is aligned with the optical coupler, so that the optical signal emanating from the optical gain material is reflected by the optical reflector and into the optical coupler.

Abstract: A hybrid optical source comprises an optical gain chip containing an optical gain material that provides an optical signal, and an optical reflector chip including an optical reflector. It also includes a semiconductor-on-insulator (SOI) chip, which comprises a semiconductor layer having a planarized surface facing the semiconductor reflector. The semiconductor layer includes: an optical coupler to redirect the optical signal to and from the planarized surface; and an optical waveguide to convey the optical signal from the optical coupler. While assembling these chips, a height of the optical gain material is referenced against the planarized surface of the semiconductor layer, a height of the optical reflector is referenced against the planarized surface of the semiconductor layer, and the optical reflector is aligned with the optical coupler, so that the optical signal emanating from the optical gain material is reflected by the optical reflector and into the optical coupler.

Abstract: A tunable laser includes a reflective silicon optical amplifier (RSOA) with a reflective end and an interface end and an array of narrow-band reflectors, which each have a different center wavelength. It also includes a silicon-photonic optical switch, having an input port and N output ports that are coupled to a different narrow-band reflector in the array of narrow-band reflectors. The tunable laser also includes an optical waveguide coupled between the interface end of the RSOA and the input of the silicon-photonic optical switch. The frequency of this tunable laser can be tuned in discrete increments by selectively coupling the input port of the silicon-photonic optical switch to one of the N output ports, thereby causing the RSOA to form a lasing cavity with a selected narrow-band reflector coupled to the selected output port. The tunable laser also includes a laser output optically coupled to the lasing cavity.

Abstract: An integrated circuit that includes a wavelength-filter layer stack (which may include silicon oxynitride) and an optical substrate (such as a silicon-on-insulator platform) is described. During operation, an optical signal received from an optical fiber or an optical waveguide is wavelength filtered into a set of wavelength-filter optical waveguides by an optical multiplexer/demultiplexer (such as an Echelle grating and/or an array waveguide grating) in the wavelength-filter layer stack. Then, wavelength-filtered optical signals are optically coupled to the optical substrate, where they are received using photodetectors. Alternatively, modulators in the optical substrate modulate wavelength-filtered modulated optical signals, which are then optically coupled to the set of wavelength-filter optical waveguides in the wavelength-filter layer stack.

Abstract: The disclosed embodiments provide a tunable laser that includes a set of M reflective silicon optical amplifiers (RSOAs) and a set of N narrow-band reflectors. It also includes a silicon-photonic optical switch, having M amplifier ports, which are coupled through a set of M optical waveguides to the set of M RSOAs, and N reflector ports, which are coupled to the set of N narrow-band reflectors. The tunable laser also includes a switching mechanism that facilitates coupling at least one selected amplifier port from the M amplifier ports with a selected reflector port from the N reflector ports, thereby causing an RSOA coupled to the selected amplifier port to form a lasing cavity with a narrow-band reflector coupled to the selected reflector port. The tunable laser also includes a laser output, which is optically coupled to the lasing cavity.

Abstract: Wellbore sensor systems and related methods are disclosed. A wellbore sensor system includes a first sensor node and a second sensor node. The first sensor node is operably coupled to a drill string at a first location. The second sensor node is operably coupled to the drill string at a second location. A method includes taking first sensor readings from the first sensor node relative to a first spatial frame of reference, and taking second sensor readings from the second sensor node relative to a second spatial frame of reference, and using the first sensor readings and the second sensor readings to estimate parameters of a mathematical transform configured to transform the second sensor readings into the first spatial frame of reference. The method also includes transforming the second sensor readings into the first spatial frame of reference with the estimated mathematical transform.