Abstract: An apparatus and method for performing joint equalization and timing recovery in coherent optical systems. The method includes equalizing signals to generate compensated polarization signals, wherein timing error in a distorted optical signal is calculated based on one of the compensated polarization signals. The method further includes performing resampling polarization signals to correct timing offset in an optical signal based on the calculated timing error. The calculated timing error may also be used to adaptively control one or more operating parameters of an external device.

Abstract: An apparatus comprising an analog-to-digital converter (ADC); a frequency-domain equalizer (FDEQ); a time-domain interpolator positioned between the ADC and the FDEQ, wherein the time domain interpolator is coupled to the ADC and the FDEQ and configured to perform a time-domain interpolation to compensate a signal sample for a plurality of ADC induced changes.

Abstract: An optical receiver comprising a frontend configured to receive an optical signal and convert the optical signal into a plurality of digital electrical signals comprising a plurality of spectrally shaped subcarrier signals carrying symbol mapped data information, and a digital signal processor (DSP) unit coupled to the frontend and configured to receive the digital signals from the frontend, demulitplex the digital signals into the subcarrier signals, and compensate chromatic dispersion (CD) for each of the subcarrier signals by applying an equalizer, wherein each of the subcarrier signals is associated with a unique tone frequency and a unique spectral shape. Also disclosed is an optical transmitter comprising a digital signal processor (DSP) unit configured to map data symbols onto a plurality of electrical subcarrier signals that are non-overlapping and spectrally shaped in a frequency domain.

Abstract: An apparatus comprising a plurality of optical transmitters coupled to a fiber, a signal generator coupled to the optical transmitters and configured to provide a single pilot tone to the optical transmitters, and a processor positioned within a feedback loop between the fiber and the optical transmitters, the processor configured to adjust a wavelength for each of the optical transmitters to lock the wavelengths. An apparatus comprising at least one processor configured to implement a method comprising receiving an optical signal comprising a pilot tone, detecting an amplitude and a phase of the pilot tone, calculating a quadrature term using the amplitude and the phase, and wavelength locking the optical signal using the quadrature term.

Abstract: A circuit board and a manufacturing method thereof are provided. According to the method, a dielectric layer is formed on a dielectric substrate, and the dielectric layer contains active particles. A surface treatment is performed on a surface of the dielectric first conductive layer is formed on the activated surface of the dielectric layer. A conductive via is formed in the dielectric substrate and the dielectric layer. A patterned mask layer is formed on the first conductive layer, in which the patterned mask layer exposes the conductive via and a part of the first conductive layer. A second conductive layer is formed on the first conductive layer and conductive via exposed by the patterned mask layer. The patterned mask layer and the first conductive layer below the patterned mask layer are removed.

Abstract: A dense wavelength-division-multiplexing (DWDM) system, comprising a plurality of laser transmitters, a wavelength division multiplexer (WDM) optically coupled to the laser transmitters and to an output optical transmission media, a coupler optically coupled to the output optical transmission media, an interferometric filter optically coupled to the coupler but not directly to the output optical transmission media, and a light reflector optically coupled to the interferometric filter and not directly to the output optical transmission media.

Abstract: An apparatus comprising a laser transmitter having a first side and a second side, a filter coupled to the first side, a detector coupled to the second side, and a temperature controller coupled to the laser transmitter and the detector. Also disclosed is an apparatus comprising at least one processor configured to implement a method comprising receiving a photocurrent of a backward light from a laser, determining a wavelength shift offset between a wavelength of the output light and a filter transmission peak, and adjusting a temperature of the laser to substantially reduce the wavelength shift and align the wavelength of the output light with the filter transmission peak.

Abstract: An apparatus and method for performing joint equalization and timing recovery in coherent optical systems. The method includes equalizing signals to generate compensated polarization signals, wherein timing error in a distorted optical signal is calculated based on one of the compensated polarization signals. The method further includes performing resampling polarization signals to correct timing offset in an optical signal based on the calculated timing error. The calculated timing error may also be used to adaptively control one or more operating parameters of an external device.

Abstract: An apparatus comprising a nonlinear lookup unit (NL-LUU) configured to add a phase shift to a signal sample to compensate for pattern dependent phase distortion, and one or more first phase adjustment units coupled to NL-LUU and configured to remove from the signal sample a nonlinear phase error from the NL-LUU, wherein the signal sample corresponds to a received signal polarization component of a polarization multiplexed (PM) coherent signal in a PM coherent optical system.

Abstract: Included is an apparatus comprising a first circuit component comprising a plurality of optical devices each having an optical input port and an optical output port. All of the optical input ports and all of the optical output ports are positioned on a first side of the circuit component. Also included is a circuit component comprising a plurality of optical devices. The circuit component further comprises a plurality of electrical inputs coupled to the optical devices and positioned on a first side of the circuit component. The circuit component also comprises a plurality of optical input ports coupled to the optical devices and positioned on a second side of the circuit component that does not share any edges with the first side.

Abstract: An apparatus comprising a plurality of laser transmitters each comprising a polarization rotator, a polarization rotator mirror coupled to the laser transmitters, and a multiplexer positioned between the laser transmitters and the polarization rotator mirror. Also included is an apparatus comprising a first rotator configured to rotate light polarization by about 45 or about ?45 degrees, a second rotator configured to rotate light polarization by about 45 or about ?45 degrees, a mirror coupled to one side of the second rotator and configured to reflect at least a portion of the light, and a wavelength division multiplexing (WDM) filter positioned between the first rotator and the second rotator.

Abstract: An apparatus comprising a plurality of optical transmitters and a wavelength locker shared by the plurality of optical transmitters. A periodic transmission filter used for wavelength locker operations is in a network communication path and shapes optical transmissions from the plurality of optical transmitters to a network. An apparatus comprising at least one processor configured to receive a pre-filter signal corresponding to part of an optical signal comprising a pilot tone and to receive a post-filter signal corresponding to a part of the optical signal that passes through a period transmission filter, wherein a filtered part of the optical signal is directed into a network. The processor is also configured to perform wavelength locking based on a quadrature detection technique that aligns an adiabatic logical one position of a modulated transmission signal with a spectral transmission peak of the period transmission filter.

Abstract: An optical receiver comprising a frame detector configured to receive a polarized signal comprising a first bit stream and a second bit stream, and further configured to identify a plurality of frames in the first bit stream and the second bit stream using a composite header, and a time-domain equalizer (TDEQ) configured to separate the first bit stream and the second bit stream using a portion of the composite header.

Abstract: An apparatus comprising a carrier comprising at least one heat-generating component and a thermoelectric cooler (TEC) coupled to a surface of the carrier, wherein the cross-sectional area of the TEC is less than the cross-sectional area of the carrier, and wherein the TEC is aligned with the heat-generating component. Included is an apparatus comprising a carrier comprising a plurality of optical transmitters and an active component, at least one TEC coupled to the surface of the carrier, and a support post coupled to the surface of the carrier, wherein the support post has a higher thermal resistivity than the TEC, wherein the cross-sectional area of the TEC is less than the cross-sectional area of the carrier, and wherein the TEC is aligned with the optical transmitters, the active component, or both.

Abstract: This present disclosure provides an optical transmission method and system. The system includes a pre-coder for pre-coding an input signal into a first pre-coded signal, an encoder/separator coupled to the first pre-coded signal and arranged to encode the first and second pre-coded signals into a first encoded signal with 0 degree phase shift and a second encoded signal with 180 degree phase shift, and an optical modulator for providing optical modulation to the first and second encoded signals with a light source such that the intensity of an output optical duo-binary (ODB) signal with frequency chirp has identical logic sequence as the input signal.

Abstract: An apparatus comprising an analog-to-digital converter (ADC); a frequency-domain equalizer (FDEQ); a time-domain interpolator positioned between the ADC and the FDEQ, wherein the time domain interpolator is coupled to the ADC and the FDEQ and configured to perform a time-domain interpolation to compensate a signal sample for a plurality of ADC induced changes.

Abstract: An integrated DWDM transmitter apparatus includes a silica-on-silicon substrate overlying a first support component. The silica-on-silicon substrate includes a silica layer overlying a silicon layer. A coefficient of thermal expansion of the first support component is substantially matched to a coefficient of thermal expansion of the silicon layer. An optical multiplexer is located within the silica layer and includes a plurality of input waveguides and at least an output waveguide. Additionally, the apparatus includes a second support component attached to a side surface of the first support component. One or more semiconductor laser array chips overlie the second support component. A coefficient of thermal expansion of the one or more semiconductor chips is substantially matched to a coefficient of thermal expansion of the second support component.

Abstract: An integrated DWDM transmitter apparatus includes a support component and a silica-on-silicon substrate overlying the support component. The support component includes a temperature adjustment component. The silica-on-silicon substrate overlies the support component and includes a silica layer and a silicon layer. The silica-on-silicon substrate includes a corresponding a substrate surface which includes a first surface region and a second surface region. In an embodiment, the two surface regions are not coplanar. The transmitter apparatus includes an optical multiplexer within the silica layer, the optical multiplexer including a plurality of input waveguides and at least an output waveguide. The transmitter apparatus also includes one or more semiconductor laser array chips overlying the first surface region of the silica-on-silicon substrate. Each of the laser array chips including two or more lasers, which are optically coupled to corresponding ones of the plurality of input waveguides.

Abstract: An integrated DWDM transmitter apparatus includes a support component and a silica-on-silicon substrate overlying the support component. The support component includes a temperature adjustment component. The silica-on-silicon substrate overlies the support component and includes a silica layer and a silicon layer. The silica-on-silicon substrate includes a corresponding a substrate surface which includes a first surface region and a second surface region. In an embodiment, the two surface regions are not coplanar. The transmitter apparatus includes an optical multiplexer within the silica layer, the optical multiplexer including a plurality of input waveguides and at least an output waveguide. The transmitter apparatus also includes one or more semiconductor laser array chips overlying the first surface region of the silica-on-silicon substrate. Each of the laser array chips including two or more lasers, which are optically coupled to corresponding ones of the plurality of input waveguides.

Abstract: An optical network transmitter comprising a fractional-bit delay module, an optical modulator coupled to the fractional-bit delay module, and a band-limiting optical filter coupled to the optical modulator. Also disclosed is a transmission system comprising a source configured to generate two complementary binary data streams, a fractional-bit delay module in communication with the source and configured to delay one of the complementary binary data streams, a modulation module in communication with the source and the fractional-bit delay module and configured to convert the undelayed complementary binary data streams and the delayed complementary binary data streams into a fractional-bit delayed optical duobinary signal, and a band-limiting node in communication with the modulation module and configured to filter and transmit the optical duobinary signal.