Wavelength division multiplexed optical communication system having variable channel spacings and different modulation formats
Granted: January 28, 2014
Patent Number:
8639118
Consistent with the present disclosure, data, in digital form, is received by a transmit nodes of an optical communication, and converted to analog signal by a digital-to-analog converter (DAC) to drive a modulator. The modulator, in turn, modulates light at one of a plurality of wavelengths in accordance with the received data. The modulated light is then transmitted over an optical communication path to a receive node. At the receive node, the modulated optical signal, as well as other…
Communication system
Granted: January 28, 2014
Patent Number:
8638817
Consistent with the present disclosure, a communication system is provided in which client data is received and provided in frames for transmission within the system. The frames include an overhead portion as well as locations that include the client data. The frames further include phase data or “virtual justifications” that periodically correct the difference between the phase represented by the data locations in the wrapper and the actual accumulated client phase. The phase data…
Polarization control in a photonic integrated circuit
Granted: January 21, 2014
Patent Number:
8634718
The present invention provides a system, apparatus and method to maintain the polarization state of an optical signal propagating within a photonic integrated circuit, or from a first photonic integrated circuit to a second photonic integrated circuit. According to various embodiments of the invention, an optical circuit is provided which includes an optical coupler configured to accept a first optical signal on a first input and a second optical signal on a second input, the second…
Anti-resonant waveguide bends
Granted: January 21, 2014
Patent Number:
8634684
The present invention provides a system, apparatus and method to maintain the polarization state of an optical signal propagating within a photonic integrated circuit, or from a first photonic integrated circuit to a second photonic integrated circuit. According to various embodiments of the invention, an optical circuit is provided which includes a waveguide having one or more bends or curved portions. The bends or curved portions of the waveguide are configured to maintain the…
Tunable optical filter
Granted: January 21, 2014
Patent Number:
8634679
Consistent with the present disclosure an optical filter is provided that preferably includes a plurality of looped or ring-shaped waveguides provided on a substrate which are coupled to one another by tunable couplers. Portions of each waveguide constitute part of each tunable coupler, which may include, for example, a Mach-Zehnder interferometer. A heater may be thermally coupled to one or both arms of the Mach-Zehnder interferometer, to thereby adjust an amount of optical coupling…
Reducing processing bias in a soft forward error correction (FEC) decoder
Granted: January 14, 2014
Patent Number:
8631305
A system is configured to receive a word that includes a group of samples; randomly select a subset of the samples; identify first samples, from the subset, with a lowest level of reliability; select another subset of the samples; identify second samples, from the other subset, with a lowest level of reliability; and create a merged subset based on selected first samples and selected second samples. The system is also configured to select a further subset of the samples; identify third…
Method and apparatus for local optimization of an optical transmitter
Granted: January 7, 2014
Patent Number:
8625997
Consistent with the present disclosure, an optical receiver is paired with an optical transmitter in a transceiver card or module, for example. During normal operation, the optical transmitter supplies optical signals for downstream transmission on a first optical communication path, and the optical receiver receives additional optical signals from a second optical communication path. During a transmitter monitoring mode (or “loopback”), however, when monitoring of transmitter…
Monitoring system employing carrier recovery
Granted: December 17, 2013
Patent Number:
8611744
The present disclosure provides a system, apparatus and method to provide for monitoring of characteristics of optical signals, as part of wavelength division multiplexed signals for example, transmitted over a network infrastructure. The characteristics of each optical signal may be monitored and maintained at desired values in order to optimize system performance. A system including a coherent detector, as part of a coherent receiver for example, may be employed to associate each…
Control of an interferometric optical polarization beam splitter
Granted: December 10, 2013
Patent Number:
8606120
The present invention provides a system, apparatus and method to control an optical polarization beam splitter. A portion of an optical output of the polarization beam splitter is converted into a corresponding electrical signal. The electrical signal is then provided to the polarization beam splitter as a control signal via a feedback loop. The polarization beam splitter controls a characteristic of the optical output of the polarization beam splitter in response to the received control…
Phase-modulated transmission control using embedded control symbols
Granted: November 26, 2013
Patent Number:
8594514
A system receives a phase-modulated signal that carries client symbols and a sequence that includes first symbols on which a first tone is to be based and having a first power level, and second symbols on which a second tone is to be based and having a second power level; processes the sequence to generate the first tone and the second tone; determines a power difference based on the first power level and the second power level; retrieves condition information that identifies a threshold…
Wavelength division multiplexed passive optical network
Granted: November 12, 2013
Patent Number:
8582975
Consistent with the present disclosure, an optical communication system, such as a passive optical network (PON), is provided that includes an optical line terminal (OLT) and a plurality of optical network units (ONUs). The OLT includes a plurality of photonic integrated circuits that have both optical transmitters and receivers provided therein. Accordingly, the OLT may have fewer components and a simpler, more reliable and cost-effective design than a conventional OLT including…
In-band control plane and management functionality in optical level one virtual private networks
Granted: November 12, 2013
Patent Number:
8582582
A method performed by an optical node, operating as a first network edge device of an optical layer one virtual private network (L1VPN), includes generating, by a first module of the optical node, a first optical data frame, where the first optical data frame includes an L1VPN overhead, and where the L1VPN overhead includes a control plane communication field; generating, by a second module of the optical node, a first control plane message for a second network edge device of the optical…
Optical shaping for amplification in a semiconductor optical amplifier
Granted: November 5, 2013
Patent Number:
8577224
The present invention provides a system, apparatus, and method for efficient optical amplification and transmission of a data-encoded optical signal within a networking device, such as a transmitter or receiver. In various embodiments of the invention, an optical duobinary signal or hybrid duobinary signal is generated and shaped in preparation for amplification of the optical signal by an SOA. The deleterious impact of SOA fast gain dynamics may be reduced by taking advantage of…
Maintaining correlated virtual data streams through a network
Granted: October 22, 2013
Patent Number:
8565610
Embodiments of the invention are described in which correlated virtual data streams are managed within an optical network connection. In certain embodiments of the invention, a client signal is allocated across a plurality of transport wavelength channels according to various transposition methods. The assignment of portions of the client signal to corresponding wavelengths may depend on various factors including channel utilization within the transport network and skew characteristics…
Wavelength and power monitor for WDM systems
Granted: October 22, 2013
Patent Number:
8565602
Consistent with the present disclosure, a transmitter is provided that includes first and second stages of wavelength locking circuitry. The first stage includes a tunable optical filter that sweeps through the spectrum of a WDM signal at a predetermined rate. A first photodiode senses a tapped portion of the output of the tunable filter. The remaining light is fed to the second stage, which includes a second optical filter, typically having a fixed transmission characteristic. A second…
Super-channel assignment using a flexible grid
Granted: October 8, 2013
Patent Number:
8553725
A node is configured to receive an instruction to establish a channel having a bandwidth that corresponds to an operating spectrum an optical fiber; obtain information that identifies a channel spacing and a pointer that identifies where, within the spectrum, to establish bandwidth allocations; identify a group of bandwidth segments based on the spectrum and the channel spacing; and generate bit words that correspond to the bandwidth allocations, where the bit words includes bits that,…
Transceiver photonic integrated circuit
Granted: October 1, 2013
Patent Number:
8548333
The present invention provides for a transceiver comprising a transmitter portion and a receiver portion. The transmitter portion includes a laser, the laser providing an optical signal having one of a plurality of wavelengths. The optical signal from the laser is modulated to create a first wavelength-division multiplexed signal at an output of the transceiver. The optical signal from the laser is also used by a demultiplexer to demultiplexer a second wavelength-division multiplexed…
Compact photonic integrated circuit having geometrically arranged active and passive regions
Granted: September 24, 2013
Patent Number:
8542958
According to this disclosure, embodiments of the present invention include photonic integrated circuits having active and passive geometric regions geometrically arranged to provide for more compact integrated photonic integrated circuits which, in turn, leads to higher chip yields and lower fabrication costs.
Coherent optical receiver
Granted: September 17, 2013
Patent Number:
8538277
A coherent optical receiver circuit is disclosed in which various components of the optical receiver may be provided or integrated, in one example, on a common substrate. Further integration is achieved by incorporating various optical demultiplexer designs that are relatively compact and conserve space on the surface of the substrate. The optical receiver circuit may be used to demultiplex quadrature phase shift keying (QPSK) optical signals.
Forward error correction (FEC) enabled photonic integrated circuit (PIC) chips with multiple signal channels
Granted: August 27, 2013
Patent Number:
8521020
A forward error correction (FEC) communication device that includes a transmitter photonic integrated circuit (TxPIC) or a receiver photonic integrated circuit (RxPIC) and a FEC device for FEC coding at least one channel with a first error rate and at least one additional channel with a second error rate, wherein the first error rate is greater than the second error rate. The TxPIC chip is a monolithic multi-channel chip having an array of modulated sources integrated on the chip, each…
