Abstract: A polarization splitter rotator includes a first lower waveguide and a second lower waveguide disposed on a first layer, the first lower waveguide and the second lower waveguide, in a first portion of the device, widening symmetrically as the first lower waveguide and the second lower waveguide extend from an input end of the device to an output end of the device, and, in a second portion of the device, at least the second lower waveguide widening further, asymmetrically, from the first lower waveguide, and a bus waveguide disposed on a second layer, above the first layer, at least partially overlapping portions of the first lower waveguide and the second lower waveguide.

Abstract: A polarization rotator includes a bus waveguide disposed on a first layer having a longitudinal axis, a first end, and a second end, and a first upper waveguide and a second upper waveguide disposed on a second layer, above the first layer, the first upper waveguide and the second upper waveguide widening as the first upper waveguide and the second upper waveguide extend from the first end to the second end. The first upper waveguide and the second upper waveguide may also symmetrically bend toward each other and then away from each other proximate the second end.

Abstract: Photonic ring modulators with high tuning efficiency and small footprint can be formed in a hybrid material platform from a silicon bus waveguide vertically coupled to an optically active compound semiconductor (e.g., III-V) ring resonator. The performance of the modulator, e.g., in terms of the tuning efficiency and the maximum insertion loss, may be optimized by suitable levels of an applied bias voltage and a heater power of a heater optionally included in the ring modulator. The disclosed hybrid photonic ring modulators may be used, e.g., in photonic transceiver circuits with high lane count.

Abstract: 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.

Abstract: Described are various configurations of optical structures having asymmetric-width waveguides. A photodetector can include parallel waveguides that have different widths, which can be connected via passive waveguide. One or more light absorbing regions can be proximate to the waveguides to absorb light propagating through one or more of the parallel waveguides. Multiple photodetectors having asymmetric width waveguides can operate to transduce light in different modes in a polarization diversity optical receiver.

Abstract: Described are various configurations of reduced crosstalk optical switches. Various embodiments can reduce or entirely eliminate crosstalk using a coupler that has a power-splitting ratio that compensates for amplitude imbalance caused by phase modulator attenuation. Some embodiments implement a plurality of phase modulators and couplers as part of a dilated switch network to increase overall bandwidth and further reduce potential for crosstalk.

Abstract: An optical coupling device can couple incident light from a fiber into waveguides, but can reduce the coupling of return light from the waveguides into the fiber. A Faraday rotator layer can rotate by forty-five degrees, with a first handedness, respective planes of polarization of incident beams, and can rotate by forty-five degrees, with a second handedness opposite the first handedness, respective planes of polarization of return beams. A redirection layer can include at least one grating coupler that can redirect an incident beam of one polarization so that the redirected path extends within the redirection layer toward a first waveguide, and can redirect an incident beam of an opposite polarization so that the redirected path extends within the redirection layer toward a second waveguide. An optional birefringent layer can spatially separate incident beam having different polarizations, so that two single-polarization grating couplers can be used.

Abstract: Described herein are methods, systems, and apparatuses to utilize an electro-optic modulator including one or more heating elements. The modulator can utilize one or more heating elements to control an absorption or phase shift of the modulated optical signal. At least the active region of the modulator and the one or more heating elements of the modulator are included in a thermal isolation region comprising a low thermal conductivity to thermally isolate the active region and the one or more heating elements from a substrate of the PIC.

Abstract: The wavelength response of an arrayed waveguide grating can be tuned, in accordance with various embodiments, using a beam sweeper including one or more heaters to shift a lateral position of light focused by the beam sweeper at an interface of the beam sweeper with an input free propagation region of the arrayed waveguide grating.

Abstract: Described herein are optical sensing devices for photonic integrated circuits (PICs). A PIC may comprise a plurality of waveguides formed in a silicon on insulator (SOI) substrate, and a plurality of heterogeneous lasers, each laser formed from a silicon material of the SOI substrate and to emit an output wavelength comprising an infrared wavelength. Each of these lasers may comprise a resonant cavity included in one of the plurality of waveguides, and a gain material comprising a non-silicon material and adiabatically coupled to the respective waveguide. A light directing element may direct outputs of the plurality of heterogeneous lasers from the PIC towards an object, and one or more detectors may detect light from the plurality of heterogeneous lasers reflected from or transmitted through the object.

Abstract: 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.

Abstract: Described are various configurations of integrated wavelength lockers including asymmetric Mach-Zehnder interferometers (AMZIs) and associated detectors. Various embodiments provide improved wavelength-locking accuracy by using an active tuning element in the AMZI to achieve an operational position with high locking sensitivity, a coherent receiver to reduce the frequency-dependence of the locking sensitivity, and/or a temperature sensor and/or strain gauge to computationally correct for the effect of temperature or strain changes.

Abstract: Described are various configurations of optical structures having asymmetric-width waveguides. A photodetector can include parallel waveguides that have different widths, which can be connected via passive waveguide. One or more light absorbing regions can be proximate to the waveguides to absorb light propagating through one or more of the parallel waveguides. Multiple photodetectors having asymmetric width waveguides can operate to transduce light in different modes in a polarization diversity optical receiver.

Abstract: Described are various configurations of reduced crosstalk optical switches. Various embodiments can reduce or entirely eliminate crosstalk using a coupler that has a power-splitting ratio that compensates for amplitude imbalance caused by phase modulator attenuation. Some embodiments implement a plurality of phase modulators and couplers as part of a dilated switch network to increase overall bandwidth and further reduce potential for crosstalk.

Abstract: 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.

Abstract: Described are various configurations of optical structures having asymmetric-width waveguides. A photodetector can include parallel waveguides that have different widths, which can be connected via passive waveguide. One or more light absorbing regions can be proximate to the waveguides to absorb light propagating through one or more of the parallel waveguides. Multiple photodetectors having asymmetric width waveguides can operate to transduce light in different modes in a polarization diversity optical receiver.

Abstract: An optical system can lock a wavelength of a tunable laser to a specified wavelength of a temperature-insensitive spectral profile of a spectral filter. In some examples, the spectral filter, such as a Fabry-Perot filter, can have a temperature-insensitive peak wavelength and increasing attenuation at wavelengths away from the peak wavelength. The spectral filter can spectrally filter the laser light to form filtered laser light. A detector can detect at least a fraction of the filtered laser light. Circuitry coupled to the detector and the laser can tune the tunable laser to set a signal from the detector to a specified value corresponding to a specified wavelength in the spectral profile, and thereby adjust the selectable wavelength of the tunable laser to match the specified wavelength. In some examples, the optical system can include a polarization rotator, and can use polarization to separate incident light from return light.

Abstract: Described are various configurations of reduced crosstalk optical switches. Various embodiments can reduce or entirely eliminate crosstalk using a coupler that has a power-splitting ratio that compensates for amplitude imbalance caused by phase modulator attenuation. Some embodiments implement a plurality of phase modulators and couplers as part of a dilated switch network to increase overall bandwidth and further reduce potential for crosstalk.

Abstract: Photonic ring modulators with high tuning efficiency and small footprint can be formed in a hybrid material platform from a silicon bus waveguide vertically coupled to an optically active compound semiconductor (e.g., III-V) ring resonator. The performance of the modulator, e.g., in terms of the tuning efficiency and the maximum insertion loss, may be optimized by suitable levels of an applied bias voltage and a heater power of a heater optionally included in the ring modulator. The disclosed hybrid photonic ring modulators may be used, e.g., in photonic transceiver circuits with high lane count.

Abstract: Described herein are optical sensing devices for photonic integrated circuits (PICs). A PIC may comprise a plurality of waveguides formed in a silicon on insulator (SOI) substrate, and a plurality of heterogeneous lasers, each laser formed from a silicon material of the SOI substrate and to emit an output wavelength comprising an infrared wavelength. Each of these lasers may comprise a resonant cavity included in one of the plurality of waveguides, and a gain material comprising a non-silicon material and adiabatically coupled to the respective waveguide. A light directing element may direct outputs of the plurality of heterogeneous lasers from the PIC towards an object, and one or more detectors may detect light from the plurality of heterogeneous lasers reflected from or transmitted through the object.