Patent application number | Description | Published |
20080279556 | Wavelength Division Multiplexed Passive Optical Network - Data is transmitted between a central office and customer premises by a wavelength division multiplex passive optical network. Two laser beams with separate wavelengths are transmitted from the central office to an optical network unit in the customer premises. Both laser beams carry downstream data. One laser beam is intensity modulated by on/off keying. The other laser beam is phase modulated by differential phase shift keying, which maintains a constant optical intensity. The first laser beam is received by a first optical receiver, which demodulates the first downstream data. The second laser beam is split in two. One laser beam is sent to a second optical receiver, which demodulates the second downstream data. The other laser beam is sent to a reflective semiconductor amplifier, which modulates the beam with upstream data and transmits the beam back to a receiver in the central optical system. | 11-13-2008 |
20090092392 | VIRTUAL I/Q MULTIPLEXING IN OPTICAL CODE DIVISION FOR SECURE LOCAL AREA OFDM - A system and method for virtual I/Q multiplexing in optical code division for secure local area OFDM includes encoding a wide spectrum signal, which includes a plurality of spectral bins, to provide a complementary spectral coding over at least two channels. The complementary spectral codings are intensity modulated with opposite polarity for each channel. An M-ary Orthogonal Frequency Division Multiplexing (OFDM) signal is modulated using the complementary spectral codings of opposite polarity with separate complementary spectral encoded (CSE) optical codes to provide a virtual in-phase (I) and quadrature (Q) (I/Q) multiplexing for the OFDM signal. | 04-09-2009 |
20090092393 | Coherent Optical Orthogonal Frequency Division Multiplexing (OFDM) Reception Using Self Optical Carrier Extraction - A method includes producing interference between a received optical OFDM signal and an optical carrier extracted from the received optical OFDM signal to provide optical coherent detection of the received optical OFDM signal. Preferably, producing the interference includes optically splitting the received optical OFDM signal into a first part that is filtered to extract the carrier from the received optical OFDM signal and a second part similar to the received optical OFDM signal. | 04-09-2009 |
20090097852 | 10 Gbps OFDMA-PON - A method for generating transparent pipes for heterogeneous service transmission via OFDMA-PON. In an exemplary embodiment, dedicated sub-channels, which are composed of one or more subcarriers—are used as a “transparent pipe” for delivery of arbitrary analog or digital signals for both circuit switched and packet switched systems. | 04-16-2009 |
20090202243 | Direct Detection For Receiving Polarization Multiplexing Signals - There is provided a method for detecting optical signals comprising employing a photo diode to both directly detect a received optical signal and convert it into an electrical signal for recovery of data bit stream information in the received optical signal, the received optical signal being derived from a separation of two polarization multiplexed optical signals that were combined before being received. | 08-13-2009 |
20090226169 | Programmable Optical Network Architecture - A programmable optical network architecture and associated components employing a two-level orthogonal frequency division multiplexing (OFDM)/wavelength division multiplexed (WDM) mechanisms for bandwith virtualization. | 09-10-2009 |
20090290877 | Monitoring for High Speed OFDM Signal Transmission - A method includes coupling an optical signal upconverted to a higher frequency and a digital signal having a bit rate similar to that of a subchannel of the upconverted optical signal, and obtaining, responsive to the coupling, a transmission signal with an optical carrier frequency carrying the digital signal and subchannels about the optical carrier frequency carrying the upconverted optical signal, the bit rate of the optical carrier being similar to that of the subchannels. In a preferred embodiment, the coupling includes electrically power coupling the upconverted optical signal with the digital signal, and modulating the coupled optical carrier frequency carrying the digital signal and subchannels about the optical carrier frequency carrying the upconverted optical signal. | 11-26-2009 |
20100027994 | Phase Modulation Of An Optical Orthogonal Frequency Division Multiplexing Signal - A method includes generating an optical orthogonal frequency division multiplexing OFDM signal with in-phase and quadrature-phase components; varying an RF carrier according to the in-phase and quadrature-phase components; and modulating a phase of a lightwave carrier according to the varied RF carrier to generate an optical OFDM signal with equalized amplitude. | 02-04-2010 |
20100028002 | PASSIVE OPTICAL NETWORK SYSTEM EMPLOYING SUB-CARRIER MULTIPLEXING AND ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS MODULATION SCHEMES - Implementations of the present principles include methods, systems and apparatuses for transmitting data through a sub-carrier multiplexing and orthogonal frequency-division multiple access passive optical network. In accordance with aspects of the present principles, a plurality of optical network units are assigned electrical carrier frequency bandwidths that are narrower than a system capacity bandwidth. Modulation of optical waves transmitted between an optical line terminal and each optical network unit is conducted on different orthogonal sub-carrier frequencies within the assigned bandwidths such that sampling of said orthogonal sub-carrier frequencies is limited to the assigned electrical carrier frequency bandwidths. The waves are thereafter received and demodulated for the extraction of data. | 02-04-2010 |
20100142637 | TRANSMITTER COMPENSATION IN DECODING OF INTENSITY MODULATED OPTICAL OFDM WITH DIRECT DETECTION - A method by an optical OFDM receiver includes converting a received optical signal to an electrical signal, deriving a digital signal from the electrical signal, and emulating, with an iterative OFDM demodulator responsive to the digital signal, a transmitter effect in the received signal of lower peak clipping and top peak distortion and applying the transmitter effect to the received signal and a decision-made signal for estimating an error function to be applied to a demodulation of the received optical signal. | 06-10-2010 |
20100215368 | SINGLE WAVELENGTH SOURCE-FREE OFDMA-PON COMMUNICATION SYSTEMS AND METHODS - Methods and systems for processing communication signals in an Orthogonal Frequency Division Multiple Access (OFDMA)-Passive Optical Network (PON) are disclosed. An optical carrier at a wavelength generated at an optical line terminal (OLT) may be reused by optical network units (ONUs) in the network for upstream transmission of data signals to the OLT. In addition, each ONU may perform carrier suppression to avoid broadband beating noise resulting from the simultaneous transmission of upstream data signals on the same wavelength. Further, the optical source at the OLT used to generate the optical carrier may be reused as a local oscillator for coherent detection of received upstream signals to minimize any frequency offsets. | 08-26-2010 |
20110069954 | On Improved Optical Network Apparatus Having Optical Line Terminal Blade Protection with 1-to-N Redundancy and No-Service-Interruption - There is provided an optical network apparatus having interconnected processing gigabit passive optical network G-PON blades, a protection blade, and controller blade, the regular blades and protecting blade having a higher layer processing and switching interface to a G-PON media access control MAC coupled to PHY including serializer and de-serializer modules that are connected to respective interface modules, the improvement including a protecting 1:N signal drive and a protecting N:1 signal select driver coupled between the interface module and serializer and de-serializer modules of the protecting blade, respectively, for protecting connection to the interface module of the protecting blade. The improvement further includes a processing 1:N signal driver and a processing N:1 signal select driver coupled between the interface module and serializer and de-serializer modules of the processing G-PON blade, respectively, for protecting connection to the interface module of the processing G-PON blade and a 1:2 signal driver and 2:1 signal select driver in the interface module for providing an alternative connection to the protection blade. | 03-24-2011 |
20110075242 | OPTICAL SIGNAL GENERATION WITH D/A CONVERTERS AND OPTICAL CLOCK PULSE STREAM - An apparatus includes an optical train pulse generator for generating continuous optical pulses each having a narrow width; a clock source having a high frequency for triggering the generator and operable as a sampling clock; a digital-to-analog converter DAC for converting an input signal from a digital signal processor, the DAC responsive to the sampling clock; a data modulator responsive to an amplified output from the DAC to modulate the continuous optical pulses from the train pulse generator; and a filter for removing higher frequency harmonics from the modulated continuous optical pulses out of the data modulator. | 03-31-2011 |
20120301157 | CHROMATIC DISPERSION COMPENSATION USING SIGN OPERATIONS AND LOOKUP TABLES - Methods and devices for compensating for chromatic dispersion are shown that include receiving an input data signal, applying a filter to the data signal, and outputting a CD compensated signal. Applying the filter includes convolving known filter coefficients with a plurality of delayed versions of the data signal using addition and at least one inverse sign operation or using lookup tables and combining outputs to produce a CD compensated signal. | 11-29-2012 |
20130091399 | HIGH-SPEED LONG CODEWORD QC-LDPC SOFT DECISION DECODER - A Quasi-Cyclic, LDPC, large girth, soft-decision decoder and accompanying methods. | 04-11-2013 |
20130108270 | VARIABLE BIT-RATE QPSK TRANSMITTER AND METHOD EMPLOYING POLARIZATION MANIPULATION | 05-02-2013 |
20150043330 | END-TO-END HITLESS PROTECTION IN PACKET SWITCHED NETWORKS - A method and system are described for providing hitless protection in a packet switched network having source nodes and destination nodes. The method includes enabling a working path and a protecting path between the source and destination nodes. The working path is non-overlapping with respect to the protecting path. The method further includes replicating traffic in a given one of the source nodes to generate replicated traffic. The method also includes forwarding the traffic and the replicated traffic through a working path and a protecting path, respectively, from the given one of the source nodes to a particular one of the destination nodes. The method additionally includes delivering a hitless-protected service in the particular one of the destination nodes by selecting traffic packets received from either the working path or the protecting path. | 02-12-2015 |
20150043331 | ADDING LINK AGGREGATION GROUP TO HITLESS PROTECTION IN PACKET SWITCHED NETWORKS - A method is provided for traffic aggregation in a hitless protected packet switched network having source and destination nodes. The method includes enabling a working path and a protecting path between the source and destination nodes. The working path is non-overlapping with respect to the protecting path. The method includes generating, using a processor, internal marker packets at working and protecting input ports of the source nodes. Each market packet represents a respective marker time period. The method includes transmitting the marker packets to working and protecting output ports of the source nodes, by the working and protecting input ports of the source nodes. The method includes selectively aggregating, at each of the working and protecting output ports of the source nodes, hitless traffic sent from different working and protecting inputs ports of the source nodes to provide an aggregated flow there from, responsive to the marker packets. | 02-12-2015 |
20150046768 | ENCODING METHOD AND SYSTEM FOR QUASI-CYCLIC LOW-DENSITY PARITY-CHECK CODE - A method and system are provided. The method includes applying a quasi-cyclic matrix M to an input vector X of encoded data to generate a vector Y. The method further includes applying a matrix Q to the vector Y to generate a vector Z. The method also includes recursively generating, using a processor, parity check bits P for the encoded data from the vector Z and an identity matrix variant I. The encoded data includes quasi-cyclic low-density parity-check code. The identity matrix variant t is composed of Toeplitz sub-matrices. | 02-12-2015 |