Abstract: Methods and systems for monolithic integration of photonics and electronics in CMOS processes are disclosed and may include fabricating photonic and electronic devices on two CMOS wafers with different silicon layer thicknesses. The devices may be fabricated on semiconductor-on-insulator (SOI) wafers utilizing a bulk CMOS process and/or on a SOI wafer utilizing a SOI CMOS process. The different thicknesses may be fabricated utilizing a double SOI process and/or a selective area growth process. Cladding layers may be fabricated utilizing one or more oxygen implants and/or utilizing CMOS trench oxide on the CMOS wafer. Silicon may be deposited on the CMOS trench oxide utilizing epitaxial lateral overgrowth. Cladding layers may be fabricated utilizing selective backside etching. Reflective surfaces may be fabricated by depositing metal on the selectively etched regions. Silicon dioxide or silicon germanium integrated in the CMOS wafer may be utilized as an etch stop layer.

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 mode converters for grating couplers may include a photonic chip comprising a waveguide, a grating coupler, and a mode converter, with the waveguide being coupled to the grating coupler via the mode converter. The mode converter may include waveguide material and tapers defined by tapered regions, where the tapered regions do not have waveguide material. The photonic chip may receive an optical signal in the mode converter from the waveguide, where the received optical signal has a light profile that may be spatially deflected in the mode converter to configure a desired profile in the grating coupler. A long axis of the tapers may be parallel to a direction of travel of the optical signal. The long axis of the tapers may point towards the input waveguide of the grating couplers, which may be linear.

Abstract: Methods and systems for a distributed optoelectronic receiver are disclosed and may include an optoelectronic receiver having a grating coupler, a splitter, a plurality of photodiodes, and a plurality of transimpedance amplifiers (TIAs). The receiver receives a modulated optical signal utilizing the grating coupler, splits the received signal into a plurality of optical signals, generates a plurality of electrical signals from the plurality of optical signals utilizing the plurality of photodiodes, communicates the plurality of electrical signals to the plurality of TIAs, amplifies the plurality of electrical signals utilizing the plurality of TIAs, and generates an output electrical signal from coupled outputs of the plurality of TIAs. Each TIA may be configured to amplify signals in a different frequency range. One of the plurality of electrical signals may be DC coupled to a low frequency TIA of the plurality of TIAs.

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 integrated multi-port waveguide photodetectors are disclosed and may include an optical receiver on a chip, where the optical receiver comprises a multi-port waveguide photodetector having three or more input ports. The optical receiver may be operable to receive optical signals via one or more grating couplers, couple optical signals to the photodetector via optical waveguides in the chip, and generate an output electrical signal based on the coupled optical signals using the photodetector. The photodetector may include four ports coupled to two PSGCs. The optical signals may be coupled to the photodetector via S-bends and/or tapers at ends of the optical waveguides. A width of the photodetector on sides that are coupled to the optical waveguides may be wider than a width of the optical waveguides coupled to the sides. Optical signals may be mixed with local oscillator signals using the multi-port waveguide photodetector.

Abstract: Methods and systems for coupling a light source assembly to an optical integrated circuit are disclosed and may include a system comprising a laser source assembly having a laser, a rotator, and a mirror, where the laser source assembly is coupled to a die including an angled grating coupler and a waveguide. The system may generate an optical signal utilizing the laser, rotate the polarization of the optical signal utilizing the rotator, reflect the rotated optical signal onto the grating coupler on the die, and couple the optical signal to the waveguide, where an angle between a grating coupler axis that is parallel to the waveguide and a plane of incidence of the optical signal reflected to the angled grating coupler is non-zero. The angle between the grating coupler axis and the plane of incidence of the optical signal reflected to the angled grating coupler may be 45 degrees.

Abstract: Methods and systems for a polarization immune wavelength division multiplexing demultiplexer are disclosed and may include, in an optoelectronic transceiver having an input coupler, a demultiplexer, and an amplitude scrambler: receiving input optical signals via the input coupler, communicating the input optical signals to the amplitude scrambler via waveguides, configuring the average optical power in each of the waveguides utilizing the amplitude scrambler, and demultiplexing the optical signals utilizing the demultiplexer. The amplitude scrambler may include phase modulators and a coupling section. The phase modulators may include sections of P-N junctions in the two waveguides. The demultiplexer may include a Mach-Zehnder Interferometer. The demultiplexed signals may be received utilizing photodetectors. The input coupler may include a polarization splitting grating coupler.

Abstract: A method and system is provided for cassette based wavelength division multiplexing and may include an optical system with an aggregating cassette. The optical system may include optical transceivers, with each generating optical signals at a different wavelength. The aggregating cassette may include one or more multiplexers coupled to each of the optical transceivers via optical fibers. The optical transceivers may generate modulated optical signals at one of the different wavelengths. The optical fibers may communicate one of the modulated optical signals from each of the optical transceivers to the one or more multiplexers. The modulated optical signals may be multiplexed to one or more output optical fibers. The multiplexed signals may be communicated to one or more receiving demultiplexers using the one or more output optical fibers. The one or more demultiplexers may demultiplex the multiplexed signals into separate wavelength signals.

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: Methods and systems for a narrowband, non-linear optoelectronic receiver are disclosed and may include amplifying a received signal, limiting a bandwidth of the received signal, and restoring the signal utilizing a level restorer, which may include a non-return to zero (NRZ) level restorer. The NRZ level restorer may include a pulse-triggered bistable circuit, which may include two parallel inverters, with one being a feedback path for the other. The inverters may be single-ended or differential. A photogenerated signal may be amplified in the receiver utilizing a transimpedance amplifier and programmable gain amplifiers (PGAs). A received electrical signal may be amplified via PGAs. The bandwidth of the received signal may be limited utilizing one or more of: a low pass filter, a bandpass filter, a high pass filter, a differentiator, or a series capacitance on the chip. The signal may be received from a photodiode integrated on the chip.

Abstract: Methods and systems for an optical coupler for photonics devices are disclosed and may include a photonics transceiver comprising a silicon photonics die, an optical source module, and a fiber connector for receiving optical fibers and including a die coupler and an optical coupling element. The die coupler may be bonded to a top surface of the photonics die and aligned above an array of grating couplers. The optical coupling element may be attached to the die coupler and the electronics die and the source module may be bonded to the top surface of the photonics die. A continuous wave (CW) optical signal may be received in the photonics die from the optical source module. Modulated optical signals may be received in the photonics die from optical fibers coupled to the fiber connector.

Abstract: Methods and systems for a low-parasitic silicon high-speed phase modulator are disclosed and may include in 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 fingers of p-doped and n-doped regions on opposite sides along a length of the PN junction waveguide. Contacts may be formed on the fingers of p-doped and n-doped regions. The fingers of p-doped and n-doped regions may be arranged symmetrically about the PN junction waveguide or staggered 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 bi-directional receiver for standard single-mode fiber based on grating couplers may include, in an integrated circuit, 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.

Abstract: Methods and systems for redundant light sources by utilizing two inputs of an integrated modulator are disclosed and may include: an optoelectronic transmitter in a semiconductor die with first and second laser sources for providing optical signals to the semiconductor die, the transmitter comprising an optical modulator with a first input waveguide coupled to the first laser source and second input waveguide coupled to the second laser source, the optoelectronic receiver being operable to: configure the first laser source to provide an optical signal to the first input of the optical modulator; and if the first laser source does not provide an optical signal, configure the second laser source to provide an optical signal to the second input of the optical modulator. The first laser source may be optically coupled to the first input waveguide and the second laser source optically coupled to the second input waveguide using grating couplers.

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: Methods and systems for waveguide delay based equalization with current and optical summing in optical communication are disclosed and may include an optoelectronic receiver including a directional coupler, two or more photodetectors, and one or more current mirrors. The optoelectronic receiver may be operable to: receive an input optical signal; split the input optical signal into first and second optical signals using the directional coupler; generate a first electrical from the first optical signal using a first photodetector; generate a second electrical signal from the second optical signal using a second photodetector; mirror the second electrical signal using the current mirror; and sum the first electrical signal with the amplified second electrical signal. The optoelectronic receiver may be operable to delay the first optical signal before generating the first electrical signal, using a waveguide delay.

Abstract: Methods and systems for waveguide delay based equalization with optical splitting in optical communication may include an optoelectronic circuit comprising an input waveguide, a directional coupler, an optical delay, photodetectors, a current mirror, and a transimpedance amplifier. The optoelectronic circuit may receive an input optical signal via the input waveguide, split the input optical signal into first and second output signals using the directional coupler, delay the first output signal using the optical delay, convert the delayed first output signal to a first electrical signal using a first photodetector, convert the second output signal to a second electrical signal using a second photodetector, amplify the second electrical signal using the current mirror, and sum the first and second electrical signals at inputs of the transimpedance amplifier to generate an output voltage.

Abstract: Methods and systems for germanium-on-silicon photodetectors without germanium layer contacts are disclosed and may include, in a semiconductor die having a photodetector, where the photodetector includes an n-type silicon layer, a germanium layer, a p-type silicon layer, and a metal contact on each of the n-type silicon layer and the p-type silicon layer: receiving an optical signal, absorbing the optical signal in the germanium layer, generating an electrical signal from the absorbed optical signal, and communicating the electrical signal out of the photodetector via the n-type silicon layer and the p-type silicon layer. The photodetector may include a horizontal or vertical junction double heterostructure where the germanium layer is above the n-type and p-type silicon layers. An intrinsically-doped silicon layer may be below the germanium layer between the n-type silicon layer and the p-type silicon layer. A top portion of the germanium layer may be p-doped.

Abstract: Methods and systems for a optical fiber connector locking clip are disclosed and may include operatively coupling an optical fiber connector to an optical fiber adaptor by inserting the optical fiber connector into the optical fiber adaptor, where the optical fiber connector comprises an optical fiber connector pull-to-release housing. The optical fiber connector may be secured to the optical fiber adaptor by placing an optical fiber locking clip adjacent to the optical fiber connector pull-to-release housing, thereby preventing the optical fiber connector pull-to-release housing from being actuated. An optical cable may be coupled to the optical fiber connector. The adaptor may be coupled to an optical device, which may include an optical transceiver. The optical fiber locking clip may be plastic or metal. The optical fiber connector and the optical fiber connector pull-to-release housing may be plastic.