Class / Patent application number | Description | Number of patent applications / Date published |
398035000 | TDM system | 14 |
20090162055 | Optical access system - An optical access system capable of avoiding cutoffs or interruption in the periodically transmitted signals that occur during the ranging time is provided. A first method to avoid signal cutoffs is to stop periodic transmit signals at the transmitter during the ranging period, and transmit all the periodic transmit signals together when the ranging ends, and buffer the signals at the receiver to prepare for ranging. A second method is to fix definite periods ahead of time for performing ranging, then cluster the multiple periodic transmit signals together in sets at the transmitter and send them, and then disassemble those sets back into signals at the receiver. The transmitting and receiving is then controlled so that the transmit periods do not overlap with the ranging periods. In this way an optical access system is provided that can send and receive signals requiring periodic transmissions without interruption even during ranging operation. | 06-25-2009 |
20090317080 | METHOD AND ARRANGEMENTS FOR IMPROVING SIGNAL QUALITY - The invention relates to a bandpass filter (OFI) which is mounted downstream of an optical amplifier (OV) and allows noise to be largely reduced. In order for said bandpass filter to be able to optimally receive burst signals (BS | 12-24-2009 |
20100178053 | OPTICAL COMMUNICATIONS SYSTEMS AND OPTICAL LINE TERMINALS - In an optical communications system in which an OLT transceiver and a plurality of ONU transceivers are connected to each other via an optical fiber and a TDMA system in which a signal from each of the ONU transceivers is issued at a timing assigned by the OLT transceiver is used, each of the ONU transceivers includes a light source which has modulation function of a Fabry-Perot laser that oscillates multi-mode lights of different wavelengths, the OLT transceiver includes a single-longitudinal-mode light source which has modulation function of a DFB laser that oscillates a single-longitudinal-mode light, and the light source which has modulation function included in each of the ONU transceivers and the single-longitudinal-mode light source which has modulation function included in the OLT transceiver are optically connected to each other via an optical fiber. | 07-15-2010 |
20110255866 | SYSTEM AND METHOD FOR SCHEDULING TIMESLOTS FOR TRANSMISSION BY OPTICAL NODES IN AN OPTICAL NETWORK - A signal strength corresponding to an incoming optical burst from each of a plurality of optical nodes is measured. The measurements can be performed at system start-up, configuration/installation of the optical nodes and/or at certain intervals of operation of the optical nodes. Signal strength information for the optical nodes based on the measurements is stored in memory. When scheduling the optical nodes for transmission, a preferred transmission order is determined in response to the stored signal strength information. In an embodiment, the preferred order is determined to reduce differences in signal strength levels between consecutive optical bursts. | 10-20-2011 |
20120114331 | PASSIVE OPTICAL NETWORK SYSTEM AND SLEEP TIME DETERMINATION METHOD - The longest possible sleep time is selected while data missing is prevented in a PON system by referring to the link speeds and the queue buffer capacities of an OLT and ONUs. The OLT calculates a first sleep time candidate based on a first link speed at which the OLT communicates with an upper network and the capacity of an unused area of a first queue buffer where downstream data is held for each of the destination ONUs. Each of the ONUs calculates a second sleep time candidate based on a second link speed at which each of the ONUs communicates with a communication terminal and the capacity of an unused area of a second queue buffer where upstream data bound for the OLT is held. The smaller sleep time is determined and used to change one of the ONUs to a sleep mode. | 05-10-2012 |
20120315034 | Detector And Method Thereof - This invention provides a detecting device and a method for a passive optical network (PON), which includes: a laser device; a detector coupled to the laser device and generating an output signal at one of a first level when the laser device emits light and a second level when the laser device does not emit light; and a processor repeatedly detecting the output signal in a fixed period, and simultaneously counting a total number of changes that the output signal changes from the first level to the second level and the output signal changes from the second level to the first level so as to detect whether a light leakage occurs in the PON. | 12-13-2012 |
20130089325 | TRANSMISSION CONTROL APPARATUS IMPROVED IN TRANSMISSION EFFICIENCY OF DOWNSTREAM DATA - In a transmission control apparatus, connected communication devices are detected to find round trip time of transmission to each of the detected communication devices, and the order of each communication device is determined on the basis of the round trip time of transmission to that communication device depending upon the distance thereto. On the basis of the round trip times of transmission to, and the orders of, the communication devices, transmission wait times are determined for delaying transmission of control signals from the communication devices to notify the communication devices of the transmission wait times. When starting communication with the communication devices, timer start signals prompting the communication devices to start counting the transmission wait time are transmitted to the communication devices. | 04-11-2013 |
20130156423 | METHOD AND APPARATUS FOR LASER OVERLAP DETECTION - There are disclosed systems and methods for detecting whether an Optical Network Unit (ONU) in a network may be causing a communications interference due to laser overlap. In one embodiment, an Optical Line Terminal (OLT) selects a pair of ONUs suspected of possibly causing laser overlap. The OLT then grants a first window to a first ONU for transmitting a first message, and grants to another ONU different from the pair of ONUs a second window for transmitting a second message. If the first message is not received by the OLT, then the OLT indicates that the first ONU may be causing laser overlap. In another embodiment, the OLT grants to an ONU a window for transmitting a message to the OLT. If the message is not received by the OLT when expected, then the OLT indicates that the ONU may be causing laser overlap. Other embodiments are disclosed. | 06-20-2013 |
20130209096 | METHOD FOR CORRECTING A DELAY ASYMMETRY - Exemplary methods and apparatuses are provided for a method for correcting for a delay asymmetry of synchronization messages transmitted within a packet-switched network between a master clock and a slave clock, in which the delay asymmetry of the path connecting the master clock to the slave clock is determined and corrected locally within at least one link of said path. One or more signals are transmitted on one or more wavelengths over at least one optical fiber. The one or more signals are received and detected on the one or more wavelengths over the at least one optical fiber. The technique determines an arrival time difference between the received and detected one or more signals, and calculates a delay asymmetry of an adjacent link based on the time difference. | 08-15-2013 |
20140105597 | NETWORK INTERFACE DEVICE SYNCHRONIZATION - Techniques are disclosed that relate to synchronizing a clock on a network interface device with a clock on an optical line terminal (OLT). In one example, the technique to synchronizing the clocks may include monitoring one or more instances when the network interface device transmits information to the OLT and determining when a frame should be received by the network interface device based on the monitored one or more instances when the network interface device transmits information the OLT. | 04-17-2014 |
20150030324 | OPTICAL TRANSMITTER - The optical transmitter includes a FP-LD, generating multiple-longitudinal mode light wave. The FP-LD is also driven by an electrical signal, modulates the electrical signal to the multiple-longitudinal mode light wave, and outputts the modulated multiple-longitudinal mode light wave. An optical coupler, coupled with the FP-LD, is used for feeding the modulated multiple-longitudinal mode light wave from the FP-LD to a fiber Bragg grating. The fiber Bragg grating is for filtering the received multiple-longitudinal mode light wave according to a parameter, and feeding back the optical signal generated after being filtered to the optical coupler. The optical coupler divides the optical signal, thus making the optical signal oscillate between the FP-LD and the fiber Bragg grating to form a oscillation cavity, and outputs a single mode optical wave with constant wavelength and power. | 01-29-2015 |
20150326312 | COLLISION CONTROL DURING DELAY MEASUREMENT IN OPTICAL TRANSPORT NETWORKS - Methods and systems for collision control during delay measurements in optical transport networks include scheduling delay measurements in time slices of a time window. At most, one delay measurement per time slice is scheduled and performed for each optical data unit (ODU) in an optical transport network (OTN). | 11-12-2015 |
20150326591 | ROGUE OPTICAL NETWORK INTERFACE DEVICE DETECTION - Techniques are described for identifying a rogue network interface device whose laser is not under control of a controller of the network interface device. The techniques identify the rogue network interface device based on reception of a predefined data pattern in a timeslot that is not reserved for any of the network interface devices without needing to disable upstream data transmission from the network interface devices during their assigned timeslots. The techniques also relate to a network interface device determining whether the network interface device is transmitting optical signals at a wavelength different than the wavelength that the OLT to which the network interface device is associated receives. | 11-12-2015 |
20150341138 | COHERENT COMMUNICATION SYSTEM, COMMUNICATION METHOD, AND TRANSMISSION METHOD - The estimation of an amount of chromatic dispersion using a training signal sequence is possible. A transmission method includes: a training signal sequence generation step of generating, as training signal sequences, a plurality of signal sequences having power concentrated in a plurality of frequency bands, the power concentrated at different frequency bands; a training signal sequence selection step of selecting at least one training signal sequence from among the plurality of training signal sequences generated in the training signal sequence generation step, a signal multiplexing step of generating a signal sequence obtained by time-division multiplexing the training signal sequence selected in the training signal sequence selection step with a transmission data sequence, and an electrical-to-optical conversion step of transmitting the signal sequence generated in the signal multiplexing step as an optical signal. | 11-26-2015 |