Abstract: Using silicon photonic components that support a single polarization, the output of an optical receiver is independent of the polarization of an optical signal. In particular, using a polarization-diversity technique, the two orthogonal polarizations in a single-mode optical fiber are split in two and processed independently. For example, the two optical signals are provided by a polarizing splitting grating coupler. Subsequently, a wavelength channel in the two optical signals is selected using a wavelength-selective filter (for example, using a ring resonator or an echelle grating) and combined at an optical detector (such as a photo-detector) to achieve polarization-independent operation.

Abstract: An integrated circuit includes an optical source that provides an optical signal to an optical waveguide. In particular, the optical source may be implemented by fusion-bonding a III-V semiconductor to a semiconductor layer in the integrated circuit. In conjunction with surrounding mirrors (at least one of which is other than a distributed Bragg reflector), this structure may provide a cavity with suitable optical gain at a wavelength in the optical signal along a vertical direction that is perpendicular to a plane of the semiconductor layer. For example, the optical source may include a vertical-cavity surface-emitting laser (VCSEL). Moreover, the optical waveguide, defined in the semiconductor layer, may be separated from the optical source by a horizontal gap in the plane of the semiconductor layer. During operation of the optical source, the optical signal may be optically coupled across the gap from the optical source to the optical waveguide.

Abstract: An integrated circuit includes an optical source that provides an optical signal to an optical waveguide. In particular, the optical source may be implemented by fusion-bonding a III-V semiconductor to a semiconductor layer in the integrated circuit. In conjunction with surrounding mirrors (at least one of which is other than a distributed Bragg reflector), this structure may provide a cavity with suitable optical gain at a wavelength in the optical signal along a vertical direction that is perpendicular to a plane of the semiconductor layer. For example, the optical source may include a vertical-cavity surface-emitting laser (VCSEL). Moreover, the optical waveguide, defined in the semiconductor layer, may be separated from the optical source by a horizontal gap in the plane of the semiconductor layer. During operation of the optical source, the optical signal may be optically coupled across the gap from the optical source to the optical waveguide.

Abstract: An integrated circuit includes a holographic recording material substantially filling a cavity in a semiconductor layer. During operation of the integrated circuit, a holographic pattern in the holographic recording is reconstructed and used to diffract an optical signal propagating in a plane of an optical waveguide, which is defined in the semiconductor layer out of the plane through the cavity. In this way, the holographic recording material may be used to couple the optical signal to an optical fiber or another integrated circuit.

Abstract: In the optical device, a ring-resonator modulator, having an adjustable resonance (center) wavelength, optically couples an optical signal that includes the carrier wavelength from an input optical waveguide to an output optical waveguide. A monitoring mechanism in the optical device, which is optically coupled to the output optical waveguide, monitors a performance metric of an output optical signal from the output waveguide. For example, the monitoring mechanism may monitor: an average optical power associated with the output optical signal, and/or an amplitude of the output optical signal. Moreover, control logic in the optical device adjusts the resonance wavelength based on the monitored performance metric so that the performance metric is optimized.

Abstract: An optical de-MUX includes a sub-wavelength grating that magnifies an input optical signal. In particular, along a direction perpendicular to a propagation direction of the optical signal, the sub-wavelength grating has a spatially varying effective index of refraction that is larger at a center of the sub-wavelength grating than at an edge of the sub-wavelength grating. Moreover, the optical de-MUX includes an optical device that images and diffracts the optical signal using a reflective geometry, and which provides different diffraction orders to output ports. For example, the optical device may include an echelle grating.

Abstract: An optical device has a waveguide immobilized on a base. A lens is defined by the base. A reflecting side reflects a light signal that travels on an optical pathway that extends through the lens and into the waveguide. The reflecting side is positioned to reflect the light signal as the light signal travels along a portion of the optical pathway between the lens and the waveguide. An optical insulator that confines the light signal within the waveguide. The portion of the optical pathway between the lens and the waveguide extends through the optical insulator such that the light signal is transmitted through the optical insulator.

Abstract: In a multiple-wavelength laser source, a multiple-mode laser outputs a set of wavelengths in a range of wavelengths onto an optical waveguide, where a spacing between adjacent wavelengths in the set of wavelengths is smaller than a width of channels in an optical link. Furthermore, a set of ring-resonator filters in the multiple-wavelength laser source, which are optically coupled to the optical waveguide, output corresponding subsets of the set of wavelengths for use in the optical link based on free spectral ranges and quality factors of the set of ring-resonator filters. These subsets may include one or more groups of wavelengths, with another spacing between adjacent groups of wavelengths that is larger than the width of the given channel in the optical link. In addition, the one or more groups of wavelengths may include one or more wavelengths, with the spacing between adjacent wavelengths in the given group of wavelengths.

Abstract: An optical device includes an optical reflector based on a coupled-loopback optical waveguide. In particular, an input port, an output port and an optical loop in arms of the optical reflector are optically coupled to a directional coupler. The directional coupler evanescently couples an optical signal between the arms. For example, the directional coupler may include: a multimode interference coupler and/or a Mach-Zehnder Interferometer (MZI). Moreover, destructive interference during the evanescent coupling determines the reflection and transmission power coefficients of the optical reflector.

Abstract: An interconnect module for communicating electrical signals and optical signals is described. In particular, an integrated circuit in the interconnect module receives and transmits the electrical signals with other components in a system that includes the interconnect module via an electrical connector. In addition, the integrated circuit receives and transmits electrical signals to a hybrid silicon-photonic bridge chip that performs electrical-to-optical and optical-to-electrical conversion. In turn, this bridge chip receives and transmits optical signals via an optical fiber. The interconnect module can be remateably connected to a backplane in the system, and can be arranged in a stacked configuration with other instances of the interconnect module. In these ways, the interconnect module facilitates dense, modular or scalable, and compact electrical and optical communication in the system.

Abstract: A photonic integrated circuit (PIC) is described. This PIC includes a grating coupler for surface-normal coupling that has an alternating pattern of grating teeth and grating trenches, where the grating trenches are filled with an electro-optical material. By applying an electric potential to the grating teeth, the index of refraction of the electro-optical material can be modified.

Abstract: A photonic integrated circuit (PIC) is described. This PIC includes a semiconductor-barrier layer-semiconductor diode in an optical waveguide that conveys an optical signal, where the barrier layer is an oxide or a high-k material. Moreover, semiconductor layers in the semiconductor-barrier layer-semiconductor diode may include geometric features (such as a periodic pattern of holes or trenches) that create a lattice-shifted photonic crystal optical waveguide having a group velocity of light that is lower than the group velocity of light in the first semiconductor layer and the second semiconductor layer without the geometric features. The optical waveguide is included in an optical modulator, such as a Mach-Zehnder interferometer (MZI).

Abstract: A hybrid optical source that provides an optical signal having a wavelength is described. This hybrid optical source includes an edge-coupled optical amplifier (such as a III-V semiconductor optical amplifier) aligned to a semiconductor reflector (such as an etched silicon mirror). The semiconductor reflector efficiently couples (i.e., with low optical loss) light out of the optical amplifier in a direction approximately perpendicular to a plane of the optical amplifier. A corresponding optical coupler (such as a diffraction grating or a mirror) fabricated on a silicon-on-insulator chip efficiently couples the light into a sub-micron silicon-on-insulator optical waveguide. The silicon-on-insulator optical waveguide couples the light to additional photonic elements (including a reflector) to complete the hybrid optical source.

Abstract: A fabrication technique for cleaving a substrate in an integrated circuit is described. During this fabrication technique, a trench is defined on a back side of a substrate. For example, the trench may be defined using photoresist and/or a mask pattern on the back side of the substrate. The trench may extend from the back side to a depth less than a thickness of the substrate. Moreover, a buried-oxide layer and a semiconductor layer may be disposed on a front side of the substrate. In particular, the substrate may be included in a silicon-on-insulator technology. By applying a force proximate to the trench, the substrate may be cleaved to define a surface, such as an optical facet. This surface may have high optical quality and may extend across the substrate, the buried-oxide layer and the semiconductor layer.

Abstract: The present invention includes an optical waveguide with a grating and a method of making the same for increasing the effectiveness of the grating. In one example, the grating is at least partially covered by a liner layer disposed on at least a portion of a grating; and a cover layer disposed on the liner layer, wherein a first material selected for the core and ridges and a second material selected for the liner layer are selected to provide a difference in the index of refraction between the first and second material that is sufficient to provide a contrast therebetween.

Abstract: An optical device with high thermal tuning efficiency is described. This optical device may be implemented using a tri-layer structure (silicon-on-insulator technology), including: a substrate, a buried-oxide layer and a semiconductor layer. In particular, a thermally tunable optical waveguide may be defined in the semiconductor layer. Furthermore, a portion of the substrate under the buried-oxide layer and substantially beneath a location of the thermally tunable optical waveguide is fabricated so that a portion of the buried-oxide layer is exposed. In this way, the thermal impedance between the thermally tunable optical waveguide and an external environment is increased, and power consumption associated with thermal tuning of the optical waveguide is reduced.

Abstract: An integrated optical source is described. This optical source outputs one or more optical signals that provide a comb of wavelengths for use in wavelength-division-multiplexing (WDM) optical interconnects or links. In particular, a shared echelle grating is used as a wavelength-selective filter or control device for multiple lasing cavities to achieve self-registered and accurate lasing-channel spacing without inter-channel gain competition. Furthermore, the optical source can be used to provide all the wavelength channels in one optical waveguide or in separate optical waveguides. Therefore, the optical source may be used with cascaded ring-resonator modulators and/or electro-absorption-based broadband modulators.

Abstract: An optical multiplexer/de-multiplexer (MUX/de-MUX) includes a two-dimensional pattern of features in a propagation region that conveys an optical signal having wavelengths. A given feature in this pattern has a characteristic length and the features have an average pitch, both of which are less than fundamental smallest of the wavelengths divided by an effective index of refraction of the propagation region. Moreover, an optical device in the optical MUX/de-MUX images and diffracts the optical signal using a reflective geometry, and provides the imaged and diffracted optical signal to output ports. For example, the optical device may include an echelle grating.

Abstract: A chip package includes an optical integrated circuit (such as a hybrid integrated circuit) and an integrated circuit that are adjacent to each in the chip package. The integrated circuit includes electrical circuits, such as memory or a processor, and the optical integrated circuit communicates optical signals with very high bandwidth. Moreover, a front surface of the integrated circuit is electrically coupled to a front surface of the optical integrated circuit by a top surface of the interposer, where the top surface faces the front surface of the integrated circuit and the front surface of the optical integrated circuit. Furthermore, the integrated circuit and the optical integrated circuit may be on a same side of the interposer. By integrating the optical integrated circuit and the integrated circuit in close proximity, the chip package may facilitate improved performance compared to chip packages with electrical interconnects.

Abstract: A chip package includes an optical integrated circuit (such as a hybrid integrated circuit) and an integrated circuit that are proximate to each other in the chip package. The integrated circuit includes electrical circuits, such as memory or a processor, and the optical integrated circuit communicates optical signals with very high bandwidth. Moreover, a front surface of the integrated circuit is electrically coupled to a top surface of an interposer, and this top surface is in turn electrically coupled to a front surface of an input/output (I/O) integrated circuit that faces the top surface. Furthermore, the front surface of the I/O integrated circuit is electrically coupled to a top surface of the optical integrated circuit, where the top surface of the optical integrated circuit faces the front surface of the I/O integrated circuit.