Abstract: A semiconductor optical amplifier for high-power operation includes a gain medium having a multilayer structure sequentially laid with a P-layer, an active layer, a N-layer from an upper portion to a lower portion in cross-section thereof. The gain medium is extendedly laid with a length L from a front facet to a back facet. The active layer includes multiple well layers formed by undoped semiconductor material and multiple barrier layers formed by n-doped semiconductor materials. Each well layer is sandwiched by a pair of barrier layers. The front facet is characterized by a first reflectance Rf and the back facet is characterized by a second reflectance Rb. The gain medium has a mirror loss ?m about 40-200 cm?1 given by: ?m=(½L)ln{1/(Rf×Rb)}.

Abstract: An integrated heatsink for a co-packaged optical-electrical module includes a base plate attached on top of a co-packaged optical-electrical module. The integrated heatsink further includes a plurality of fin structures extended upward from the base plate except a central cavity region with missing sections of fins, each fin extended along an axial direction from a front edge to a back edge of the base plate except some trenches shallow in depth across some fin structures and some other trenches deep in depth down to the base plate either along or across some fin structures. Additionally, the integrated heatsink includes multiple heat pipes including shaped portions embedded in the trenches in the plurality of fin structures. At least one bottom horizontal portion per heat pipe is brazed to the base plate in a corresponding region that is superimposed on hot spots of the co-packaged optical-electrical module under the base plate.

Abstract: The present application discloses a Transverse Electric (TE) polarizer. The TE polarizer includes a semiconductor substrate having an oxide layer. The TE polarizer further includes a waveguide embedded in the oxide layer. Additionally, the TE polarizer includes a plate structure embedded in the oxide layer substantially in parallel to the waveguide with a gap distance. In an embodiment, the plate structure induces an extra transmission loss to a Transverse Magnetic (TM) mode in a light wave traveling through the waveguide.

Abstract: A silicon optical modulator includes two silicon waveguide branches coupled between a 2×2 splitter at a common input end and a 2×2 splitter at a common output end. The modulator further includes at least one of the two silicon waveguide branches comprising a ridge-shape having a central portion of a height sandwiched in a width direction by a first side portion and a second side portion throughout a length of the waveguide. The central portion in each cross-section plane thereof includes a p-region and a n-region separated by a continuous borderline to form an irregular shaped PN junction. The borderline is configured to have at least one section-line with a sloped angle relative to the width direction and have a total border-length substantially longer than the height. The p-region is in contact with the first side portion and the n-region is in contact with the second side portion.

Abstract: The present invention is directed to data communication. More specifically, an embodiment of the present invention provides an error correction system. Input data signals are processed by a feedforward equalization module and a decision feedback back equalization module. Decisions generated by the decision feedback equalization module are processed by an error detection module, which determines error events associated with the decisions. The error detection module implements a reduced state trellis path. There are other embodiments as well.

Abstract: The present invention is directed to communication methods and systems thereof. In a specific embodiment, a noise cancelation system includes a slicer that processes a data stream generates both PAM symbols and error data. An RIN estimator generates RIN data based on the PAM symbols and the error data. A filter removes non-RIN information from the RIN data. The filtered RIN data includes an offset term and a gain term, which are used to remove RIN noise from the data stream. There are other embodiments as well.

Abstract: A package structure of a directly modulated laser in a photonics module includes a thermoelectric cooler including multiple conductor traces formed in a cool surface. The package structure further includes a directly modulated laser (DML) chip having a first electrode being attached with the cool surface and a second electrode at a distance away from the cool surface. Additionally, the package structure includes an interposer having a plurality of through-holes formed between a first surface to a second surface. The first surface is mounted to the cool surface such that each through-hole is aligned with one of the multiple conductor traces and the second surface being leveled with the second electrode. Moreover, the package structure includes a driver disposed on the second surface of the interposer with at least a galvanically coupled output port coupled directly to the second electrode of the DML chip.

Abstract: A method and structure for compensation techniques in coherent optical receivers. The present invention provides a coherent optical receiver with an improved 8×8 adaptive MIMO (Multiple Input, Multiple Output) equalizer configured within a digital signal processor (DSP) to compensate the effects of transmitter I/Q skew in subcarrier multiplexing (SCM) schemes. The 8×8 MIMO equalizer can be configured such that each of the 8 outputs is electrically coupled to 3 of 8 inputs, wherein each of the input-output couplings is configured as a filter. The method includes compensating for impairments to the digital conversion of an optical input signal via the 8×8 MIMO equalizer following other signal processing steps, such as chromatic dispersion (CD)/polarization-mode dispersion (PMD) compensation, carrier recovery, timing synchronization, and cycle slip correction.

Abstract: An optical dispersion compensator integrated with a silicon photonics system including a first phase-shifter coupled to a second phase-shifter in parallel on the silicon substrate characterized in an athermal condition. The dispersion compensator further includes a third phase-shifter on the silicon substrate to the first phase-shifter and the second phase-shifter through two 2×2 splitters to form an optical loop. A second entry port of a first 2×2 splitter is for coupling with an input fiber and a second exit port of a second 2×2 splitter is for coupling with an output fiber. The optical loop is characterized by a total phase delay tunable via each of the first phase-shifter, the second phase-shifter, and the third phase-shifter such that a normal dispersion (>0) at a certain wavelength in the input fiber is substantially compensated and independent of temperature.

Abstract: A device and method of operation for digital compensation of dynamic distortion. The transmitter device includes at least a digital-to-analog converter (DAC) connected to a lookup table (LUT), a first shift register, and a second shift register. The method includes iteratively adjusting the input values via the LUT to induce changes in the DAC output that compensate for dynamic distortion, which depends on precursors, current cursors, and postcursors. More specifically, the method includes producing and capturing average output values for each possible sequence of three symbols using the shift register and LUT configuration. Then, the LUT is updated with estimated values to induce desired output values that are adjusted to eliminate clipping. These steps are performed iteratively until one or more check conditions are satisfied. This method can also be combined with techniques such as equalization, eye modulation, and amplitude scaling to introduce desirable output signal characteristics.

Abstract: A receiver system that includes a clock and data recovery (CDR) system for aligning a local clock signal to an incoming data signal to extract correct timing information from the incoming data signal is provided. A timing error detector generates an output phase error signal representing the phase difference between the incoming data signal and the local clock signal. The timing error detector determines the phase difference according to recovered symbols and the difference between the recovered symbols and digital samples of the incoming data signal. The digital samples of the incoming data signal include intersymbol interference. The output timing information is suitable for aligning the local clock signal to the incoming data signal.

Abstract: An integrated differential Electro-Absorption Modulator (EAM) device. The device includes a substrate, an electrical driver, and two EAM modules. The electrical driver circuit is configured overlying the substrate member and has one output electrically coupled to the first EAM module and the other output electrically coupled to the second EAM module. The first and second EAM modules have a first and a second output, respectively. A beam splitter can be configured to split an optical input into two optical outputs, each of which can be optically coupled to the optical inputs of the first and second EAM modules.

Abstract: A receiver applies a calibration method to compensate for skew between input channels. The receiver skew is estimated by observing the coefficients of an adaptive equalizer which adjusts the coefficients based on time-varying properties of the multi-channel input signal. The receiver skew is compensated by programming the phase of the sampling clocks for the different channels. Furthermore, during real-time operation of the receiver, channel diagnostics is performed to automatically estimate differential group delay and/or other channel characteristics based on the equalizer coefficients using a frequency averaging or polarization averaging approach. Framer information can furthermore be utilized to estimate differential group delay that is an integer multiple of the symbol rate. Additionally, a DSP reset may be performed when substantial signal degradation is detected based on the channel diagnostics information.

Abstract: A method and structure for signal propagation in a coherent optical receiver device. Asynchronous equalization helps to reduce complexity and power dissipation, and also improves the robustness of timing recovery. However, conventional devices using inverse interpolation filters ignore adaptation algorithms. The present invention provides for forward propagation and backward propagation. In the forward case, the filter input signal is forward propagated through a filter to the adaptation engine, while, in the backward case, the error signal is backward propagated through a filter to the asynchronous domain. Using such forward and backward propagation schemes reduces implementation complexity while providing optical device performance.

Abstract: A light source based on integrated silicon photonics includes a die of a silicon substrate having at least one chip site configured with a surface region, a trench region, and a first stopper region located separately between the surface region and the trench region. The trench region is configured to be a depth lower than the surface region. The light source includes a laser diode chip having a p-side facing the chip site and a n-side being distal to the chip site. The p-side includes a gain region bonded to the trench region, an electrode region bonded to the surface region, and an isolation region engaged with the stopper region to isolate the gain region from the electrode region. The light source also includes a conductor layer in the die configured to connect the gain region to an anode electrode and separately connect the electrode region to a cathode electrode.

Abstract: An integrated apparatus with optical/electrical interfaces and protocol converter on a single silicon substrate. The apparatus includes an optical module comprising one or more modulators respectively coupled with one or more laser devices for producing a first optical signal to an optical interface and one or more photodetectors for detecting a second optical signal from the optical interface to generate a current signal. Additionally, the apparatus includes a transmit lane module coupled between the optical module and an electrical interface to receive a first electric signal from the electrical interface and provide a framing protocol for driving the one or more modulators. Furthermore, the apparatus includes a receive lane module coupled between the optical module and the electrical interface to process the current signal to send a second electric signal to the electrical interface.

Abstract: The present invention is directed to data communication. More specifically, embodiments of the present invention provide a transceiver that processes an incoming data stream and generates a recovered clock signal based on the incoming data stream. The transceiver includes a voltage gain amplifier that also performs equalization and provides a driving signal to track and hold circuits that hold the incoming data stream, which is stored by shift and holder buffer circuits. Analog to digital conversion is then performed on the buffer data by a plurality of ADC circuits. Various DSP functions are then performed over the converted data. The converted data are then encoded and transmitted in a PAM format. There are other embodiments as well.

Abstract: The present invention is directed to data communication system and methods. More specifically, various embodiments of the present invention provide a communication interface that is configured to transfer data at high bandwidth using nDSQ format(s) over optical communication networks. In certain embodiments, the communication interface is used by various devices, such as spine switches and leaf switches, within a spine-leaf network architecture, which allows large amount of data to be shared among servers.

Abstract: A method and structure for tap centering in a coherent optical receiver device. The center of gravity (CG) of the filter coefficients can be used to evaluate a proper convergence of a time-domain adaptive equalizer. However, the computation of CG in a dual-polarization optical coherent receiver is difficult when a frequency domain (FD) adaptive equalizer is adopted. In this case, the implementation of several inverse fast-Fourier transform (IFFT) stages is required to back time domain impulse response. Here, examples of the present invention estimate CG directly from the FD equalizer taps and compensate for an error of convergence based off of the estimated CG. This estimation method and associated device architecture is able to achieve an excellent tradeoff between accuracy and complexity.

Abstract: An apparatus for dissipating heat from a photonic transceiver module. The apparatus includes a top-plate member disposed in a length direction of a package for the photonic transceiver module. The apparatus further includes multiple fins formed on the top-plate member along the length direction from a backend position to a frontend position except at least one fin with a shorter length, forming an elongated void from the backend position to one backend of the at least one fin. Additionally, the apparatus includes a cover member disposed over the multiple fins with a horizontal sheet, two vertical side sheets, and a flange bent vertically from a middle portion of backend of the horizontal sheet. Furthermore, the apparatus includes a spring loaded in the elongated void between the flange and the one backend of the at least one fin to minimize an air gap at the backend of the horizontal sheet.