Patent application number | Description | Published |
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 |
20090310966 | DIRECT DETECTION RECEIVER USING CROSS-POLARIZATION INTERFEROMETER FOR POLMUX-ASK SYSTEM - A differential delay detection system and method includes an optical splitter to split an incoming optical signal between a first path and a second path. The first path includes a cross-polarization interferometer configured to separately generate polarization independent outputs using split paths and to generate cross-polarization interference outputs, balanced photodetectors to aid in removing cross-polarization beating noise, and a polarization demultiplexer configured to combine the polarization independent outputs and the cross-polarization interference outputs from the cross-polarization interferometer with updated coefficients received from the second path to remove the cross-polarization mixed signals. The second path includes a training signal receiver configured to compute the updated coefficients and output the updated coefficients to the polarization demultiplexer. | 12-17-2009 |
20100028001 | Generation Of At Least 100 Gbit/s Optical Transmission - A method includes generating at least two lightwave carriers from a lightwave source, the carriers having a wavelength spacing, creating an up-subchannel and a down-subchannel orthogonal to one another and spaced apart based on the fixed wavelength spacing from modulations of the lightwave carriers according to respective up-converted OFDM signals that are carrier suppressed, and combining one lightwave from the up-subchannel and one lightwave from the down-subchannel into an optical channel for transmission over an optical fiber. | 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 |
20100086314 | Method and Apparatus for an Optical Duty Cycle for an Optical Digital Coherent System - An optical apparatus includes a quadrature phase shift keying modulator for generating a non-return-to-zero quadrature phase shift keyed NRZ-QPSK signal from a received lightwave, the modulator being driven by a radio frequency RF signal, an intensity modulator for carving the NRZ-QPSK signal to return-to-zero RZ pulses with a different duty cycle than that of the NRZ-QPSK, the intensity modulator being driven by a radio frequency RF clock signal to change the NRZ-QPSK to an RZ-QPSK signal, and an optical filter with a narrow band for filtering the signal from the intensity modulator to increase optical power that is useable by an optical digital coherent detection system. | 04-08-2010 |
20100208853 | FEEDBACK ADJUSTABLE CONSTELLATION DE-MAPPER - A system and method to adjust the symbol constellation used to de-map a signal in an optical coherent communications system. A feedback de-mapper adjustment module is configured to compare average Error Vector Magnitude and Bit Error Ratio to a pre-defined table to determine when a constellation de-mapper mismatch occurs. The feedback de-mapper adjustment module then rotates the de-mapper constellation in order to compensate for phase drift. | 08-19-2010 |
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 |
20100329696 | 16 Quadrature Amplitude Modulation Optical Signal Transmitter - An optical transmitter including a dividing optical coupler for dividing a lightwave onto optical paths; a first optical modulator in a first of the optical paths and driven by an I component of a first signal and a I component of a second signal for modulating the lightwave, a DC bias of the first optical modulator being at a quadrature point; a second optical modulator in a second of the optical paths and driven by a Q component of the first signal and a Q component of the second signal for modulating the lightwave, a DC bias of the second optical modulator being at the quadrature point; a phase shifter for generating a 90 degree phase shift in the Q components of the first and second signals that are modulated by the second optical coupler; and a combining optical coupler for combining the modulated lightwave from the first optical coupler and the phase shifted Q components of the first and second signals for generating a quadrature amplitude modulated signal. | 12-30-2010 |
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 |