Abstract: Methods and systems for silicon photonics wavelength division multiplexing transceivers are disclosed and may include, in a transceiver integrated in a silicon photonics chip: generating a first modulated output optical signal at a first wavelength utilizing a first electrical signal, generating a second modulated output optical signal at a second wavelength utilizing a second electrical signal, communicating the first and second modulated output optical signals into an optical fiber coupled to the chip utilizing a multiplexing grating coupler in the chip. A received input optical signal may be split into a modulated input optical signal at the first wavelength and a modulated input optical signal at the second wavelength utilizing a demultiplexing grating coupler in the chip. The first and second modulated input optical signals may be converted to first and second electrical input signals utilizing first and second photodetectors in the chip.

Abstract: Methods and systems for a connectionless integrated optical receiver and transmitter test are disclosed and may include an optoelectronic transceiver comprising a transmit (Tx) path and a receive (Rx) path, with each path comprising optical switches. The transceiver may be operable to: generate a first modulated optical signal utilizing a modulator in the Tx path, couple the first modulated optical signal to a first optical switch in the Rx path via a second optical switch in the Tx path when the optoelectronic transceiver is configured in a self-test mode, receive a second modulated optical signal via a grating coupler in the Rx path when the optoelectronics transceiver is configured in an operational mode, and communicate the second modulated optical signal to a photodetector in the Rx path via the first optical switch. The first modulated optical signal may be communicated to a grating coupler in the Tx path via the second optical switch.

Abstract: A system for integrated power combiners is disclosed and may include receiving optical signals in input optical waveguides and phase-modulating the signals to configure a phase offset between signals received at a first optical coupler, where the first optical coupler may generate output signals having substantially equal optical powers. Output signals of the first optical coupler may be phase-modulated to configure a phase offset between signals received at a second optical coupler, which may generate an output signal having an optical power of essentially zero and a second output signal having a maximized optical power. Optical signals received by the input optical waveguides may be generated utilizing a polarization-splitting grating coupler to enable polarization-insensitive combining of optical signals. Optical power may be monitored using optical detectors. The monitoring of optical power may be used to determine a desired phase offset between the signals received at the first optical coupler.

Abstract: Methods and systems for a low-parasitic silicon high-speed phase modulator are disclosed and may include fabricating an optical phase modulator that comprises a PN junction waveguide formed in a silicon layer, wherein the silicon layer may be on an oxide layer and the oxide layer may be on a silicon substrate. The PN junction waveguide may have p-doped and n-doped regions on opposite sides along a length of the PN junction waveguide, and portions of the p-doped and n-doped regions may be removed. Contacts may be formed on remaining portions of the p-doped and n-doped regions. Portions of the p-doped and n-doped regions may be removed symmetrically about the PN junction waveguide. Portions of the p-doped and n-doped regions may be removed in a staggered fashion along the length of the PN junction waveguide. Etch transition features may be removed along the p-doped and n-doped regions.

Abstract: A method and system for optoelectronic receivers utilizing waveguide heterojunction phototransistors (HPTs) integrated in a wafer are disclosed and may include receiving optical signals via optical fibers operably coupled to a top surface of the chip. Electrical signals may be generated utilizing HPTs that detect the optical signals. The electrical signals may be amplified via voltage amplifiers, or transimpedance amplifiers, the outputs of which may be utilized to bias the HPTs by a feedback network. The optical signals may be coupled into opposite ends of the HPTs. A collector of the HPTs may comprise a silicon layer and a germanium layer, a base may comprise a silicon germanium alloy with germanium composition ranging from 70% to 100%, and an emitter including crystalline or poly Si or SiGe. The optical signals may be demodulated by communicating a mixer signal to a base terminal of the HPTs.

Abstract: A method and system for coupling optical signals into silicon optoelectronic chips are disclosed and may include coupling one or more optical signals into a back surface of a CMOS photonic chip comprising photonic, electronic, and optoelectronic devices. The devices may be integrated in a front surface of the chip and one or more optical couplers may receive the optical signals in the front surface of the chip. The optical signals may be coupled into the back surface of the chip via one or more optical fibers and/or optical source assemblies. The optical signals may be coupled to the grating couplers via a light path etched in the chip, which may be refilled with silicon dioxide. The chip may be flip-chip bonded to a packaging substrate. Optical signals may be reflected back to the grating couplers via metal reflectors, which may be integrated in dielectric layers on the chip.

Abstract: Methods and systems for selectable parallel optical fiber and WDM operation may include an optoelectronic transceiver integrated in a silicon photonics die. The optoelectronic transceiver may, in a first communication mode, communicate continuous wave (CW) optical signals from an optical source module to a first subset of optical couplers on the die for processing signals in optical modulators in accordance with a first communications protocol, and in a second communication mode, communicate the CW optical signals to a second subset of optical couplers for processing signals in the optical modulators in accordance with a second communications protocol. Processed signals may be transmitted out of the die utilizing a third subset of the optical couplers. First or second protocol optical signals may be received from the fiber interface coupled to a fourth subset or a fifth subset, respectively, of the optical couplers.

Abstract: Methods and systems for grating couplers incorporating perturbed waveguides are disclosed and may include in a semiconductor photonics die, communicating optical signals into and/or out of the die utilizing a grating coupler on the die, where the grating coupler comprises perturbed waveguides. The perturbed waveguides may include rows of continuous waveguides with scatterers extending throughout a length of said perturbed waveguides a variable width along their length. The grating coupler may comprise a single polarization grating coupler comprising perturbed waveguides and a non-perturbed grating. The grating coupler may comprise a polarization splitting grating coupler (PSGC) that includes two sets of perturbed waveguides at a non-zero angle, or a plurality of non-linear rows of discrete shapes. The PSGC may comprise discrete scatterers at an intersection of the sets of perturbed waveguides. The grating coupler may comprise individual scatterers between the perturbed waveguides.

Abstract: Methods and systems for optical power monitoring of a light source coupled to a silicon integrated circuit (chip) are disclosed and may include, in a system comprising an optical source coupled to the chip: emitting a primary beam from a front facet of a laser in the optical source assembly and a secondary beam from a back facet of the laser, directing the primary beam to an optical coupler in the chip, directing the secondary beam to a surface-illuminated photodiode in the chip, and monitoring an output power of the laser utilizing an output signal from the photodiode. The primary beam may comprise an optical source for a photonics transceiver in the chip. The focused primary beam and the secondary beam may be directed to the chip using reflectors in a lid of the optical source.

Abstract: Methods and systems for accurate gain adjustment of a transimpedance amplifier using a dual replica and servo loop is disclosed and may include, in a transimpedance amplifier (TIA) circuit comprising a first TIA, a second TIA, and a third TIA, each comprising a configurable feedback impedance, and a control loop, where the control loop comprises a gain stage with inputs coupled to outputs of the first and second TIAs and an output coupled to the configurable feedback impedance of the second and third TIAs: configuring a gain level of the first TIA by configuring its feedback impedance, configuring a gain level of the third TIA by configuring a reference current applied to an input of the first TIA, and amplifying a received electrical signal to generate an output voltage utilizing the third TIA. The reference current may generate a reference voltage at one of the inputs of the gain stage.

Abstract: A transceiver comprising a chip, a semiconductor laser, and one or more photodetectors, the chip comprising optical and optoelectronic devices and electronic circuitry, where the transceiver is operable to: communicate, utilizing the semiconductor laser, an optical source signal into the chip, generate first optical signals in the chip based on the optical source signal, transmit the first optical signals from the chip via a light pipe with a sloped reflective surface coupled to the chip, and receive second optical signals from the light pipe and converting the second optical signals to electrical signals via the photodetectors. The optical signals may be communicated out of and in to a top surface of the chip. The one or more photodetectors may be integrated in the chip. The optoelectronic devices may include the one or more photodetectors integrated in the chip. The light pipe may be a planar lightwave circuit (PLC).

Abstract: Methods and systems for a distributed optical transmitter with local domain splitting is disclosed and may include, in an optical modulator integrated in a silicon photonics chip: receiving electrical signals, communicating the electrical signals to domain splitters along a length of waveguides of the optical modulator utilizing one or more delay lines, generating electrical signals in voltage domains utilizing the domain splitters, modulating received optical signals in the waveguides of the optical modulator by driving diodes with the electrical signals generated in the voltage domains, and generating a modulated output signal through interference of the modulated optical signal in the waveguides of the optical modulator. The delay lines may comprise one delay element per domain splitter, or may comprise a delay element per domain splitter for a first subset of the domain splitters and more than one delay element per domain splitter for a second subset of the domain splitters.

Abstract: Methods and systems for a photonic interposer are disclosed and may include receiving one or more continuous wave (CW) optical signals in a silicon photonic interposer from an external optical source, from an optical source assembly via optical fibers coupled to the silicon photonic interposer. A modulated optical signal may be generated by processing the received CW optical signals based on a first electrical signal received from the electronics die. A second electrical signal may be generated in the silicon photonic interposer based on the generated modulated optical signals, and may then be communicated to the electronics die via copper pillars. Optical signals may be communicated into and/or out of the silicon photonic interposer utilizing grating couplers. The electronics die may comprise one or more of: a processor core, a switch core, memory, or a router.

Abstract: Methods and systems for partial integration of wavelength division multiplexing and bi-directional solutions are disclosed and may include, an optical transceiver on a silicon photonics integrated circuit coupled to a planar lightwave circuit (PLC). The silicon photonics integrated circuit may include a first modulator and first light source that operates at a first wavelength and a second modulator and second light source that operates at a second wavelength. The transceiver and PLC are operable to modulate a first continuous wave (CW) optical signal from the first light source utilizing the first modulator and modulate a second CW optical signal from the second light source utilizing the second modulator. The modulated signals may be communicated from the modulators to the PLC utilizing a first pair of grating couplers in the IC and combined in the PLC.

Abstract: A method and system for implementing high-speed electrical interfaces between semiconductor dies in optical communication systems are disclosed and may include communicating electrical signals between a first die and a second die via coupling pads which may be located in low impedance points in Tx and Rx paths. The electrical signals may be communicated via one or more current-mode, controlled impedance, and/or capacitively-coupled interfaces. The current-mode interface may include a cascode amplifier stage split between source and drain terminals of transistors on the dies. The controlled-impedance interfaces may include transmission line drivers on a first die and transmission lines on a second die. The capacitively-coupled interfaces may include capacitors formed by contact pads on the dies. The coupling pads may be connected via one or more of: wire bonds, metal pillars, solder balls, or conductive resin. The dies may comprise CMOS and may be coupled in a flip-chip configuration.

Abstract: Methods and systems for split voltage domain receiver circuits are disclosed and may include amplifying complementary received signals in a plurality of partial voltage domains. The signals may be combined into a single differential signal in a single voltage domain. Each of the partial voltage domains may be offset by a DC voltage from the other partial voltage domains. The sum of the partial domains may be equal to a supply voltage of the integrated circuit. The complementary signals may be received from a photodiode. The amplified received signals may be amplified via stacked common source amplifiers, common emitter amplifiers, or stacked inverters. The amplified received signals may be DC coupled prior to combining. The complementary received signals may be amplified and combined via cascode amplifiers. The voltage domains may be stacked, and may be controlled via feedback loops. The photodetector may be integrated in the integrated circuit.

Abstract: Methods and systems for a low-voltage integrated silicon high-speed modulator may include an optical modulator comprising first and second optical waveguides and two optical phase shifters, where each of the two optical phase shifters may comprise a p-n junction with a horizontal section and a vertical section and an optical signal is communicated to the first optical waveguide. A portion of the optical signal may then be coupled to the second optical waveguide. A phase of at least one optical signal in the waveguides may be modulated utilizing the optical phase shifters. A portion of the phase modulated optical signals may be coupled between the two waveguides, thereby generating two output signals from the modulator. A modulating signal may be applied to the phase shifters which may include a reverse bias.

Abstract: Methods and systems for a low-parasitic silicon high-speed phase modulator are disclosed and may include fabricating an optical phase modulator that comprises a PN junction waveguide formed in a silicon layer, wherein the silicon layer may be on an oxide layer and the oxide layer may be on a silicon substrate. The PN junction waveguide may have p-doped and n-doped regions on opposite sides along a length of the PN junction waveguide, and portions of the p-doped and n-doped regions may be removed. Contacts may be formed on remaining portions of the p-doped and n-doped regions. Portions of the p-doped and n-doped regions may be removed symmetrically about the PN junction waveguide. Portions of the p-doped and n-doped regions may be removed in a staggered fashion along the length of the PN junction waveguide. Etch transition features may be removed along the p-doped and n-doped regions.

Abstract: Methods and systems for a silicon-based optical phase modulator with high modal overlap are disclosed and may include, in an optical modulator having a rib waveguide in which a cross-shaped depletion region separates four alternately doped sections: receiving an optical signal at one end of the optical modulator, modulating the received optical signal by applying a modulating voltage, and communicating a modulated optical signal out of an opposite end of the modulator. The modulator may be in a silicon photonically-enabled integrated circuit which may be in a complementary-metal oxide semiconductor (CMOS) die. An optical mode may be centered on the cross-shaped depletion region. The four alternately doped sections may include: a shallow depth p-region, a shallow depth n-region, a deep p-region, and a deep n-region. The shallow depth p-region may be electrically coupled to the deep p-region periodically along the length of the modulator.

Abstract: Methods and systems for a bi-directional receiver for standard single-mode fiber based on grating couplers may include, in an integrated circuit comprising an optoelectronic transceiver, a multi-wavelength grating coupler, and first and second optical sources coupled to the integrated circuit: coupling first and second source optical signals at first and second wavelengths into the photonically-enabled integrated circuit using the first and second optical sources, where the second wavelength is different from the first wavelength, receiving a first optical data signal at the first wavelength from an optical fiber coupled to the multi-wavelength grating coupler, and receiving a second optical data signal at the second wavelength from the optical fiber. Third and fourth optical data signals at the first and second wavelengths may be communicated out of the optoelectronic transceiver via the multi-wavelength grating coupler.