Abstract: A turning grating coupler device comprises a waveguide core layer including a grating structure and an output slab adjoined with the grating structure. The grating structure comprises an array of sub-waveguides substantially parallel to each other along a first propagation direction. Each of the sub-waveguides has opposing sidewalls, and a width of each sub-waveguide is defined by a distance between the sidewalls. The width of each sub-waveguide is varied such that each of the sidewalls has a periodic structure that produces a sidewall periodic modulation that is out of phase with respective sidewall periodic modulations of adjacent neighboring sub-waveguides. An input edge is configured to receive a light beam from a source and direct the beam into the array of sub-waveguides in the first propagation direction. The sub-waveguides are configured to diffract the beam into the output slab in a second propagation direction substantially perpendicular to the first propagation direction.

Abstract: A turning grating coupler device comprises a waveguide core layer including a grating structure and an output slab adjoined with the grating structure. The grating structure comprises an array of sub-waveguides substantially parallel to each other along a first propagation direction. Each of the sub-waveguides has opposing sidewalls, and a width of each sub-waveguide is defined by a distance between the sidewalls. The width of each sub-waveguide is varied such that each of the sidewalls has a periodic structure that produces a sidewall periodic modulation that is out of phase with respective sidewall periodic modulations of adjacent neighboring sub-waveguides. An input edge is configured to receive a light beam from a source and direct the beam into the array of sub-waveguides in the first propagation direction. The sub-waveguides are configured to diffract the beam into the output slab in a second propagation direction substantially perpendicular to the first propagation direction.

Abstract: In an example, an integrated optical circuit (IOC) includes a first substrate formed of a first material and a first waveguide formed of a second material and positioned on the first substrate. The first waveguide includes a plurality of branches and is configured to polarize light beams that propagate through the first waveguide. The IOC further includes a second substrate formed of a third material, the second substrate coupled to or positioned on the first substrate. The IOC further includes a plurality of straight waveguides formed in the second substrate, each of the plurality of straight waveguides optically coupled to a respective branch of the plurality of branches of the first waveguide. The IOC further includes a plurality of electrodes positioned proximate to the plurality of straight waveguides, the plurality of electrodes configured to modulate the phase of light beams that propagate through the plurality of straight waveguides.

Abstract: An optical phase modulator comprises a cascaded array of optical resonators, wherein each of the optical resonators has an input port and an output port. A plurality of waveguides are coupled between the optical resonators and are configured to provide cascaded optical communication between the optical resonators. Each of the waveguides is respectively coupled between the output port of one optical resonator and the input port of an adjacent optical resonator. A transmission electrode is positioned adjacent to the optical resonators, with the transmission electrode configured to apply a drive voltage across the optical resonators. The optical phase modulator is operative to co-propagate an input optical wave with the drive voltage, such that a resonator-to-resonator optical delay is matched with a resonator-to-resonator electrical delay.

Abstract: Improved architectures and related methods for enhancing entangled photon generation in optical systems are described. Photons from a light source are coupled from the fundamental mode into an optical resonator in a higher-order mode. The optical resonator comprises a photon generation portion configured to generate entangled photons from the coupled photons. The entangled photons are selectively extracted from the optical resonator in the fundamental mode while the remaining photons propagate through the optical resonator mode and combine with the source photons entering the optical resonator. While the source photons propagating or entering the optical resonator resonate within the optical resonator, the entangled photons are not resonant with the optical resonator, and are selectively extracted before traversing a complete cycle in the optical resonator. Extracted entangled photons can then be output for use in, for example, a communication system.

Abstract: Improved architectures and related methods for enhancing entangled photon generation in optical systems are described. Photons from a light source are coupled from the fundamental mode into an optical resonator in a higher-order mode. The optical resonator comprises a photon generation portion configured to generate entangled photons from the coupled photons. The entangled photons are selectively extracted from the optical resonator in the fundamental mode while the remaining photons propagate through the optical resonator mode and combine with the source photons entering the optical resonator. While the source photons propagating or entering the optical resonator resonate within the optical resonator, the entangled photons are not resonant with the optical resonator, and are selectively extracted before traversing a complete cycle in the optical resonator. Extracted entangled photons can then be output for use in, for example, a communication system.

Abstract: A multilayer waveguide coupler comprising a first grating and a second grating is provided. Each first copropagating waveguide of the first grating has a first periodically modulated width. Each second copropagating waveguide of the second grating has a second periodically modulated width. The second grating is positioned so that a phase offset is present between the first periodically modulated width of the first copropagating waveguides and the second periodically modulated width of the second copropagating waveguides. The grating spaced distance and phase offset are selected so that light diffracted out of the first copropagating waveguides and the second copropagating waveguides in the first direction interferes constructively to form the first light beam and light diffracted out of the first copropagating waveguides and the second copropagating waveguides in the second direction interferes destructively.

Abstract: A sensor system comprises a pulsed light source, and a passive sensor head chip in communication with the light source. The sensor head chip includes a first photonics substrate, a transmitting optical component on the first photonics substrate and configured to couple a pulse, transmitted through a first optical fiber from the light source, into a region of interest; and a receiving optical component on the first photonics substrate and configured to couple backscattered light, received from the region of interest, into a second optical fiber. A signal processing chip communicates with the sensor head chip and light source. The signal processing chip includes a second photonics substrate and comprises a passive optical filter array that receives the backscattered light from the second optical fiber. The filter array includes notch filters in communication with each other and operative for frequency selection; and optical detectors respectively coupled to the notch filters.

Abstract: A multilayer waveguide coupler comprising a first grating and a second grating is provided. Each first copropagating waveguide of the first grating has a first periodically modulated width. Each second copropagating waveguide of the second grating has a second periodically modulated width. The second grating is positioned so that a phase offset is present between the first periodically modulated width of the first copropagating waveguides and the second periodically modulated width of the second copropagating waveguides. The grating spaced distance and phase offset are selected so that light diffracted out of the first copropagating waveguides and the second copropagating waveguides in the first direction interferes constructively to form the first light beam and light diffracted out of the first copropagating waveguides and the second copropagating waveguides in the second direction interferes destructively.

Abstract: Improvements to optical power regulation in a gyroscopic system are described. The system can include an optical assembly (e.g., optical bench) which couples opposing optical signals to a resonator coil. The system can monitor the power of the optical signals through the resonator coil by including signal extraction optics in the optical assembly which are configured to extract a portion of the optical signals. The portions can be extracted via a single beamsplitter, wherein the beamsplitter reflects the portions at a single common surface, and can also reflect the portions to a respective photodetector in free space free from intervening optical components, such as polarizers or beamsplitters. One or more processors can be coupled to the optical assembly, wherein the processor(s) are configured to adjust the power of the optical signals in response to detecting a power difference between the optical signals.

Abstract: In an example, an integrated optical circuit (IOC) includes a first substrate formed of a first material and a first waveguide formed of a second material and positioned on the first substrate. The first waveguide includes a plurality of branches and is configured to polarize light beams that propagate through the first waveguide. The IOC further includes a second substrate formed of a third material, the second substrate coupled to or positioned on the first substrate. The IOC further includes a plurality of straight waveguides formed in the second substrate, each of the plurality of straight waveguides optically coupled to a respective branch of the plurality of branches of the first waveguide. The IOC further includes a plurality of electrodes positioned proximate to the plurality of straight waveguides, the plurality of electrodes configured to modulate the phase of light beams that propagate through the plurality of straight waveguides.

Abstract: An electro-optic modulator comprises a resonator comprising a first waveguide having a first end and second end; a first grating at the first end; and a second grating at the second end. An input channel is in communication with the resonator, and comprises a second waveguide having a first end and second end; an input port at the first end; a third grating at the second end; and a first coupler configured to couple light between the second waveguide and the first waveguide. An output channel is in communication with the resonator, and comprises a third waveguide having a first end and second end; an all-pass filter at the first end; a readout port at the second end; and a second coupler configured to couple light between the first and third waveguides. The all-pass filter is configured to adjust a coupling strength between the second coupler and the readout port.

Abstract: Improvements to optical power regulation in a gyroscopic system are described. The system can include an optical assembly (e.g., optical bench) which couples opposing optical signals to a resonator coil. The system can monitor the power of the optical signals through the resonator coil by including signal extraction optics in the optical assembly which are configured to extract a portion of the optical signals. The portions can be extracted via a single beamsplitter, wherein the beamsplitter reflects the portions at a single common surface, and can also reflect the portions to a respective photodetector in free space free from intervening optical components, such as polarizers or beamplitters. One or more processors can be coupled to the optical assembly, wherein the processor(s) are configured to adjust the power of the optical signals in response to detecting a power difference between the optical signals.

Abstract: In an example, an integrated optical circuit (IOC) includes a first substrate formed of a first material and a first waveguide formed of a second material and positioned on the first substrate. The first waveguide includes a plurality of branches and is configured to polarize light beams that propagate through the first waveguide. The IOC further includes a second substrate formed of a third material, the second substrate coupled to or positioned on the first substrate. The IOC further includes a plurality of straight waveguides formed in the second substrate, each of the plurality of straight waveguides optically coupled to a respective branch of the plurality of branches of the first waveguide. The IOC further includes a plurality of electrodes positioned proximate to the plurality of straight waveguides, the plurality of electrodes configured to modulate the phase of light beams that propagate through the plurality of straight waveguides.

Abstract: In an example, an optical coupler includes a waveguide structure. The waveguide structure includes a waveguide layer having a proximal end and a distal end. The waveguide layer includes a first waveguide that extends from the proximal end along a first portion of the waveguide layer and widens along a second portion of the first waveguide layer toward the distal end. The waveguide layer further includes one or more additional waveguides that extend from the proximal end along the first portion of the waveguide layer. Each of the one or more additional waveguides narrow along the second portion of the waveguide layer to separate distal tips at the distal end. The waveguide structure is configured to match an integrated photonics mode to a fiber mode supported by an optical fiber at the proximal end and transition the mode to only the first waveguide toward the distal end.

Abstract: An optical phased array comprises a first substrate layer, and a first device array on the first substrate layer. The first device array includes a first set of emitters and a first set of waveguides. Each waveguide in the first set of waveguides is respectively coupled to one of the emitters in the first set of emitters. A second substrate layer is over the first substrate layer in a stacked configuration, and a second device array is on the second substrate layer. The second device array includes a second set of emitters and a second set of waveguides. Each waveguide in the second set of waveguides is respectively coupled to one of the emitters in the second set of emitters. The second sets of emitters and waveguides are positioned on the second substrate to be offset with respect to the first sets of emitters and waveguides on the first substrate.

Abstract: In an example, an optical coupler includes a waveguide structure. The waveguide structure includes a waveguide layer having a proximal end and a distal end. The waveguide layer includes a first waveguide that extends from the proximal end along a first portion of the waveguide layer and widens along a second portion of the first waveguide layer toward the distal end. The waveguide layer further includes one or more additional waveguides that extend from the proximal end along the first portion of the waveguide layer. Each of the one or more additional waveguides narrow along the second portion of the waveguide layer to separate distal tips at the distal end. The waveguide structure is configured to match an integrated photonics mode to a fiber mode supported by an optical fiber at the proximal end and transition the mode to only the first waveguide toward the distal end.

Abstract: A resonant fiber optic gyroscope (RFOG) comprises two integrated photonics interfaces coupling the optical resonator coil to the multi-frequency laser source that drives the RFOG; wherein the two integrated photonics interfaces comprise a first waveguide layer and a second waveguide layer wherein the first waveguide layer comprises two waveguide branches which come together to form a single waveguide branch; the second waveguide layer comprises two waveguide branches which remain separate from each other; and wherein the waveguide structure is configured to match an integrated photonics mode to a fiber mode supported by an optical fiber.

Abstract: In an example, an integrated optical circuit (IOC) includes a first substrate formed of a first material and a first waveguide formed of a second material and positioned on the first substrate. The first waveguide includes a plurality of branches and is configured to polarize light beams that propagate through the first waveguide. The IOC further includes a second substrate formed of a third material, the second substrate coupled to or positioned on the first substrate. The IOC further includes a plurality of straight waveguides formed in the second substrate, each of the plurality of straight waveguides optically coupled to a respective branch of the plurality of branches of the first waveguide. The IOC further includes a plurality of electrodes positioned proximate to the plurality of straight waveguides, the plurality of electrodes configured to modulate the phase of light beams that propagate through the plurality of straight waveguides.

Abstract: An optical phase modulator comprises a cascaded array of optical resonators, wherein each of the optical resonators has an input port and an output port. A plurality of waveguides are coupled between the optical resonators and are configured to provide cascaded optical communication between the optical resonators. Each of the waveguides is respectively coupled between the output port of one optical resonator and the input port of an adjacent optical resonator. A transmission electrode is positioned adjacent to the optical resonators, with the transmission electrode configured to apply a drive voltage across the optical resonators. The optical phase modulator is operative to co-propagate an input optical wave with the drive voltage, such that a resonator-to-resonator optical delay is matched with a resonator-to-resonator electrical delay.