Abstract: Conventional high performance computer connections are electron-based systems, which require the memory packages to be as close as mechanically possible to the computation engine. Low power and high bandwidth communication, e.g. photonic, links can drastically change the architecture of high-performance computers by eliminating the bottlenecks in communication and augment existing memory systems to allow them to be both high capacity and high bandwidth simultaneously.

Abstract: An integrated optical device fabricated in the back end of line process located within the vertical span of the metal stack and having one or more advantages over a corresponding integrated optical device fabricated in the silicon on insulator layer.

Abstract: Photonic chip includes an external cavity (EC) optical circuit to provide wavelength-selective optical feedback to a length of active optical fiber. Light generated in the active optical fiber may be coupled from the EC circuit to a light processing circuit of the photonic chip, such as an optical modulator or an optical mixer. The EC circuits may include single-frequency and multi-frequency optical filters, which may include ring resonators, dual-ring resonators, and optical modulators to support multi-frequency lasers. The EC circuits may further include pump combiners and optical isolators.

Abstract: A photonic chip includes a device layer and a port layer, with an optical port located at the port layer. Inter-layer optical couplers are provided for coupling light between the device and port layers. The inter-layer couplers may be configured to couple signal light but block pump light or other undesired wavelength from entering the device layer, operating as an input filter. The port layer may accommodate other light pre-processing functions, such as optical power splitting, that are undesirable in the device layer.

Abstract: A photonic interface for an electronic circuit is disclosed. The photonic interface includes a photonic integrated circuit having a modulator and a photodetector, and an optical fiber or fibers for optical communication with another optical circuit. A modulator driver chip may be mounted directly on the photonic integrated circuit. The optical fibers may be placed in v-grooves of a fiber support, which may include at least one lithographically defined alignment feature for optical alignment to the silicon photonic circuit.

Abstract: An optical modulator apparatus may include a plurality of segment drivers, each segment driver having a unique offset voltage and driving but a portion or a segment of an electro-optical modulator. A modulating electrical signal may be applied to the segment drivers via a plurality of electrical delays. Parameters of the segment drivers may be selected so as to approximate a pre-defined transfer function, which may include a linear or a non-linear transfer function.

Abstract: A low loss high extinction ratio on-chip polarizer is disclosed. The polarizer includes an input waveguide taper having an outer waveguiding region that widens in the direction of light propagation along at least a portion of the taper length, and a core waveguiding region that narrows in the direction of light propagation along at least a portion of the taper length, so as to selectively squeeze out light of undesired modes into the outer regions while preserving light of a desired mode in the waveguide core. An output filter section is provided to prevent light from reentering the output waveguide after being squeezed out. An integrated light absorber/deflector may be coupled to the outer waveguiding regions.

Abstract: Conventional systems use a polarization-maintaining fiber (PMF) in order to maintain the light in the same polarization between a laser light source and an optical waveguide on a photonic integrated circuit (PIC). A polarization controller may be provided at an input port of the PIC configured for the manipulation of one or both of the TE0 and TM0 polarized light modes. The polarization controller may include a polarization beam splitter/rotator (PBSR), including a plurality of phase tuners and a plurality of couplers which are coupled together by waveguides, all of which are integrated in a device layer on the PIC.

Abstract: Conventional systems use a polarization-maintaining fiber (PMF) in order to maintain the light in the same polarization between a laser light source and an optical waveguide on a photonic integrated circuit (PIC). A polarization controller may be provided at an input port of the PIC configured for the manipulation of one or both of the TE0 and TM0 polarized light modes. The polarization controller may include a polarization beam splitter/rotator (PBSR), including a plurality of phase tuners and a plurality of couplers which are coupled together by waveguides, all of which are integrated in a device layer on the PIC.

Abstract: A compact, low-loss and wavelength insensitive Y-junction for submicron silicon waveguides. The design was performed using FDTD and particle swarm optimization (PSO). The device was fabricated in a 248 nm CMOS line. Measured average insertion loss is 0.28±0.02 dB across an 8-inch wafer. The device footprint is less than 1.2 ?m×2 ?m, orders of magnitude smaller than MMI and directional couplers.

Abstract: Photonic chip includes an external cavity (EC) optical circuit to provide wavelength-selective optical feedback to a length of active optical fiber. Light generated in the active optical fiber may be coupled from the EC circuit to a light processing circuit of the photonic chip, such as an optical modulator or an optical mixer. The EC circuits may include single-frequency and multi-frequency optical filters, which may include ring resonators, dual-ring resonators, and optical modulators to support multi-frequency lasers. The EC circuits may further include pump combiners and optical isolators.

Abstract: A coherent optical receiver for AM optical signals has a photonic integrated circuit (PIC) as an optical front-end. The PIC includes a polarization beam splitter followed by two optical hybrids each followed by an opto-electric (OE) converter. Each OE converter includes one or more differential detectors and one or more squaring circuits, which outputs may be summed. The PIC may further include integrated polarization controllers, wavelength demultiplexers, and/or tunable dispersion compensators.

Abstract: In Mach-Zehnder interferometer (MZI) based modulators (MZM) input laser light comes in from one side, gets split into two MZI arms, then recombined at an opposite side. Each MZI arm may be phase or intensity modulated depending on the set phase offset, whereby coherent or intensity modulation may be performed which can later be de-coded by a receiver. Ring resonator type modulators (RRM) are compact; however, their phase response is nonlinear, normally limiting their application in coherent phase modulation. However, a combined MZI RRM overcomes the shortcomings of the prior art by providing a novel structure and driving scheme for use with semiconductor photonics that takes advantage of the compactness of ring modulators and the linearity of MZI by setting the ring resonators to resonate at the input laser light wavelength.

Abstract: In conventional hybrid lasers large back refection may lead to a degradation of relative intensity noise (RIN), linewidth broadening, mode hopping, etc. To solve the aforementioned problem a hybrid laser includes a mode converter for converting a higher-back-reflection mode of the light to a mode providing less back reflection to the gain chip. The mode converter may comprise a polarization rotator, a waveguide converter, or high-order mode converter. A routing waveguide may be provided including a phase shifter, e.g. a doped waveguide, for adjusting a cavity length of the laser cavity.

Abstract: Described are various embodiments of a dual optical modulator, system and method. In one embodiment, an optical modulator modulates an input optical signal having a designated optical frequency. The modulator comprises first and second tunable modulators operable around the optical frequency and operatively disposed between a bus waveguide path and an opposed waveguide path. The modulator further comprises a relative optical phase-shifter optically coupled between the tunable modulators so to impart a relative optical phase shift between the bus waveguide path and the opposed waveguide path. The tunable modulators are respectively driveable to modulate a respective resonance thereof in complimentary directions relative to the optical frequency and thereby resonantly redirect a selectable portion of the input optical signal along the opposed waveguide path such that the relative optical phase shift is imparted thereto for output.

Abstract: In conventional hybrid lasers large back refection may lead to a degradation of relative intensity noise (RIN), linewidth broadening, mode hopping, etc. To solve the aforementioned problem a hybrid laser includes a mode converter for converting a higher-back-reflection mode of the light to a mode providing less back reflection to the gain chip. The mode converter may comprise a polarization rotator, a waveguide converter, or high-order mode converter. A routing waveguide may be provided including a phase shifter, e.g. a doped waveguide, for adjusting a cavity length of the laser cavity.

Abstract: A coherent optical receiver for AM optical signals has a photonic integrated circuit (PIC) as an optical front-end. The PIC includes a polarization beam splitter followed by two optical hybrids each followed by an opto-electric (OE) converter. Each OE converter includes one or more differential detectors and one or more squaring circuits, which outputs may be summed. The PIC may further include integrated polarization controllers, wavelength demultiplexers, and/or tunable dispersion compensators.

Abstract: A Ge-on-Si photodetector constructed without doping or contacting Germanium by metal is described. Despite the simplified fabrication process, the device has responsivity of 1.24 A/W, corresponding to 99.2% quantum efficiency. Dark current is 40 nA at ?4 V reverse bias. 3-dB bandwidth is 30 GHz.

Abstract: An integrated polarization splitter and rotator (PSR) employs the TE0 and TE1 modes of propagating light, rather than the TE0 and TM0 modes used in conventional prior art PSR. The integrated PSR exhibits appreciably flatter wavelength response because it does not require a directional coupler to de-multiplex incoming polarizations. The PSR allows tuning of the TM0 loss to reduce polarization dependent loss (PDL). This integrated polarization splitter and rotator is applicable to all integrated platforms including Silicon-on-Insulator (SOI) and III-V semiconductor compound systems. The PSR may be very compact (12×2 ?m2), and provides low loss (<0.3 dB across the C-band) and ultra-broadband operation. The PSR also affords better control of polarization dependent losses.

Abstract: An optical device that includes means for thermal stabilization and control is described. The optical device can be a ring resonator, or another device that requires accurate control of the phase of the optical signal. In an example involving an optical resonator, a thermal stabilization system includes a temperature sensor, a control circuit, and a heater local to the resonator. The temperature sensor can be a bandgap temperature sensor formed of a pair of matched p/n junctions biased in operation at different junction currents.