Class / Patent application number | Description | Number of patent applications / Date published |
398154000 | Including synchronization | 68 |
20080247764 | Method and System For Synchronising an Optical Transmitter With an Optical Modulator - A method of synchronising an optical transmitter and modulator comprising transmitting a calibration sequence of pulses from the transmitter to the modulator; varying a control timing drawn from the set comprising the transmit interval timings and the modulator transmission interval timings; monitoring the resulting pulses transmitted by the modulator and selecting a preferred control timing; controlling the optical transmitter and/or modulator responsive to the selected control timing. Corresponding apparatus, systems, signals and programs for computers to implement or control the arrangement are also provided. | 10-09-2008 |
20080285981 | Method And System For An Asymmetric Optical Phy Operation For Ethernet A/V Bridging And Ethernet A/V Bridging Extensions - Optical signals may be communicated with A/V Bridging services between an upstream link partner and a down stream link partner, each comprising an asymmetric Ethernet optical physical layer (PHY). High bandwidth A/V optical signals may be transmitted from the upstream link partner and low bandwidth optical signals may be transmitted from the downstream link partner. One or more of a time stamp, a traffic class and/or a destination address may be utilized in generating PDUs and managing communications via the asymmetric Ethernet optical PHY. The receiving link partner may register for deliver of the PDUs. An aggregate communication rate may be distributed evenly or unevenly among one or more optical links for transmission and aggregated upon reception via asymmetric Ethernet optical PHY operations. Compressed, uncompressed, encrypted and/or unencrypted optical signals may be handled. Signal processing may comprise forward error checking and clock recovery. | 11-20-2008 |
20080310857 | OPTICAL SPACE TRANSMISSION METHOD AND OPTICAL SPACE TRANSMISSION APPARATUS - An optical identification signal generation section electrical-to-optical-converts and emits identification information. A modulation section modulates information data in a predetermined modulation type determined from the identification information. An optical data signal generation section electrical-to-optical-converts and emits the modulated information data. A two-dimensional optical-to-electrical conversion section receives the optical identification signal and acquires screen information including an image of the optical identification signal. An information reading section reads predetermined pixel information from the screen information and reproduces the identification information. An optical-to-electrical conversion section optical-to-electrical-converts the optical data signal. A demodulation section demodulates the information data in the predetermined demodulation type determined from the identification information, and reproduces the information data. A screen display section displays and updates the screen information, and displays the content of the information data in a predetermined manner from the identification information. | 12-18-2008 |
20090034984 | SONET METHOD AND SYSTEM HAVING NETWORK SERVICE ACCESS POINT ADDRESSING - A synchronous optical network (SONET) system having multi-hierarchal network service access point (NSAP) addressing includes electrically linked network elements (NEs) and first and second level routing areas which each include at least one NE. The NEs include devices having respective NSAP addresses and at least one of the NEs is a network controller that controls the SONET. The first level routing area and the second level routing areas are based on a predetermined prioritization of the NEs as first level NEs and second level NEs, and have a first level routing and having a second level routing for the NSAP addresses, respectively. Each NSAP address includes a Routing Domain field and an Area field filled with information indicative of a respective Internet Protocol (IP) address. | 02-05-2009 |
20090103929 | Synchronous optical bus providing communication between computer system components - A synchronous optical bus system for communication between computer system components is described. In one example, the optical bus system is used for communication between a memory controller and memory devices optically coupled to an optical interconnect. Optical bus interface units couple the components to the optical interconnect and are arranged on the optical interconnect in order that a sum of an optical path length from a controller component to each computer system component and from each computer system component to the controller component is the same for all the coupled computer system components. A synchronous protocol is used for communication between the components. | 04-23-2009 |
20090123159 | SYSTEM AND METHOD FOR DATA SYNCHRONIZATION IN PASSIVE OPTICAL NETWORKS - System and method for data synchronization in Passive Optical Networks. According to an embodiment, the present invention provides a method for providing upstream data synchronization in an optical communication network. The method includes sending data from an Optical Network Unit. The data includes a first data frame, which includes a header sequence, a synchronization segment, and a data segment. The synchronization segment includes 66 bits, which includes a first number of bits having nonzero values and a second number of bits having a value of zero. The first number is different from the second number. The method further includes receiving at least the first data frame by an Optical Line Terminal. The method also includes processing the first data frame. The method additionally includes selecting a first segment of the first data frame, the first segment including 66 bits. | 05-14-2009 |
20090123160 | BIT SYNCHRONIZATION CIRCUIT WITH PHASE TRACKING FUNCTION - A bit synchronization circuit comprising an initial phase determining unit for rapidly determining, during a period of receiving a preamble of burst data, a clock with a phase synchronized with received burst data from among multi-phase clocks having the same frequency as an internal reference clock and a phase tracking unit for modifying the synchronized phase clock responsive to phase variation of received data during a period of receiving a payload of burst data by taking the synchronized phase clock determined by the initial phase determining unit as an initial phase. The bit synchronization circuit retimes burst data with a data retiming clock having a predetermined phase relation with the synchronized phase clock and outputs the burst data in synchronization with the internal reference clock. | 05-14-2009 |
20090129784 | Scanning method and system for a multiple light beam system - A method and system for scanning a multiple light beam system, such as a safety light curtain, uses a plurality of transmission signals including two or more synchronization signals for synchronizing a beam receiver module with a beam transmission module. The system has transmitter circuitry which generates the transmission signals for driving light sources of the transmission module and receiver circuitry which receives corresponding transmitted signals. The receiver circuitry generates a scanning initialization signal using an uninterrupted synchronization signal among the reception signals for synchronizing the receiver module with the transmission module and scans the receiver module in response to generation of the scanning initialization signal. | 05-21-2009 |
20090169218 | OPTICAL TRANSMISSION DEVICE, OPTICAL TRANSMISSION SYSTEM, AND BANDWIDTH CONTROL METHOD - A system and method of transmitting client data encoded according to an 8B/10B encoding between a client side and an optical communication network side, including inserting padding signals in an amount corresponding to a rate difference between a clock on the client side and a clock in the optical transmission device and controlling a clock to be used as a reference in transmitting the client data to synchronize with a clock having been used as a reference in transmitting the client data on the basis of a ratio of padding signals having been inserted in the client data. | 07-02-2009 |
20090232513 | OPTICAL SIGNAL SYNCHRONIZATION SAMPLING APPARATUS AND METHOD, AND OPTICAL SIGNAL MONITORING APPARATUS AND METHOD USING THE SAME - An electroabsorption optical modulator used as a sampling element has two optical terminals and a power supply terminal, the two optical terminals are used to input and output light, and the power supply terminal imparts an electric field to an optical path connecting the two optical terminals. The electroabsorption optical modulator has a characteristic in which an absorption index is changed with respect to the light beam propagating through the optical path according to a level of the electric field. A monitoring (synchronization sampling) object optical signal is input into one of the two optical terminals of the electroabsorption optical modulator. A predetermined direct-current voltage exhibiting a high absorption index for the monitoring (synchronization sampling) object optical signal is imparted to the power supply terminal of the electroabsorption optical modulator. A sampling optical pulse is input into another of the two optical terminals of the electroabsorption optical modulator through a photocoupler. The absorption index for the monitoring (synchronization sampling) object optical signal is lowered by a mutual absorption saturation characteristic of the electroabsorption optical modulator, and synchronization sampling of the monitoring (synchronization sampling) object optical signal is performed to supply an optical signal from the other of the two optical terminals of the electroabsorption optical modulator through the photocoupler. The mutual absorption saturation characteristic is generated when the sampling optical pulse is input into the other of the two optical terminals. | 09-17-2009 |
20090297163 | Reference-clock selection circuit and reference-clock selection method - A reference-clock selection circuit for a communication interface apparatus in which signals are input via a plurality of channels includes an insertion-stuff-bit-amount monitoring unit that monitors an insertion stuff bit amount to be inserted in the signal; a channel detecting unit that detects a channel where the insertion stuff bit amount inserted in the signal matches an insertion stuff bit amount of a reference signal from a reference clock oscillator; and a reference-clock selecting unit that selects the detected channel as a reference clock for network synchronization of a connected network. | 12-03-2009 |
20090297164 | OPTICAL TRANSMISSION SYSTEM AND SYNCHRONIZATION METHOD USING TIME REFERENCE PULSE - An OLT includes a first transmitter and receiver unit for transmitting and receiving signals with ONUs, a first communication control timer, a measurement unit for measuring a round trip time (RTT) between the OLT and each of ONUs, an advance notice time generation unit for generating an advance notice time signal by adding a predetermined time to a time information that indicates a time in the first communication control timer in response to a first time reference pulse, and a unit for controlling the first transmitter and receiver unit to transmit the generated advance notice time signal to each of the ONUs, and to transmit signals indicating measured RTT/2 to the respective ones of the ONUs. | 12-03-2009 |
20090324243 | SCALABLE LOAD-BALANCED INTERCONNECT SWITCH BASED ON AN OPTICAL SWITCH FABRIC HAVING A BANK OF WAVELENGTH-SELECTIVE SWITCHES - According to one embodiment, an interconnect switch has an optical switch fabric (OSF) having N input ports and N output ports. The OSF has a bank of optically interconnected wavelength-selective switches and is adapted to route optical signals from the input ports to the output ports. In a fully deployed implementation, the interconnect switch has N input line cards and N output line cards. Each of the input line cards is adapted to generate N respective modulated optical signals using carrier wavelengths that are controllably selected from more than N carrier wavelengths to provide wavelength redundancy for optically connecting the input line card and any of the output line cards. In a partially deployed implementation, the interconnect switch has fewer than N input line cards and/or fewer than N output line cards. In either the fully deployed implementation or a partially deployed implementation, the interconnect switch is capable of load balancing. | 12-31-2009 |
20090324244 | PHOTOMETRIC DEVICE - A photometric device with a wide dynamic range. The photometric device includes a constant current generation circuit, a fixed clock signal generation circuit which generates a fixed clock signal having a fixed frequency, a photoelectric conversion element, a variable clock signal generation circuit and a digital signal generation circuit. The fixed clock signal generation circuit generates a fixed clock signal that oscillates at a fixed frequency, from constant current The variable clock signal generation circuit generates a variable clock signal that oscillates at a frequency proportional to the amount of photocurrent, from photocurrent generated in the photoelectric conversion element. The digital signal generation circuit sets a measurement period using the fixed clock signal, counts the number of pulses of the variable clock signal that oscillates for the measurement period, and outputs a digital signal including the count value as data. | 12-31-2009 |
20100008677 | Multichannel Optical Transport Network Skew Calibration - A system and method are provided for calibrating skew in a multichannel optical transport network (OTN) transmission device. The method accepts a pair of 2 | 01-14-2010 |
20100080570 | Multichannel Optical Transport Network Optical Detection Skew Calibration - A system and method are provided for calibrating temporal skew in a multichannel optical transport network (OTN) transmission device. The method accepts a pair of 2 | 04-01-2010 |
20100098432 | CLOCK REGENERATION FOR OPTICAL COMMUNICATIONS - A system and method for regenerating a client clock signal for use in optical communications is disclosed. The system and method involves using a carrier clock signal and a client clock signal to calculate quantities of data that are received and transmitted at an edge node and then adjusting a clock source in response to the difference between the calculated quantities of received and transmitted data. | 04-22-2010 |
20100142971 | APPARATUS FOR SYNCHRONIZING DIGITAL SIGNALS OF COHERENT OPTICAL RECEIVER - Provided is a digital signal synchronization device of a coherent optical receiver. The digital signal synchronization device includes a digital signal processing unit to perform synchronization on a digital signal of an output optical signal generated by interfering an optical signal received through an optical fiber with an optical signal of laser output from a local oscillator and to perform decoding using the synchronized digital signal, and a digital signal managing unit to monitor the digital signal processing unit to output data of the optical signal normally, which has been received through the optical fiber, according to the synchronized digital signal. | 06-10-2010 |
20100172653 | Optical Transmission System, Optical Transmitter for Optical Transmission System, and Optical Receiver for Optical Transmission System - An optical transmission system is provided in which the optimum operating point of a Mach-Zehnder interferometer, matched to the optical frequency of the light source on the transmitting side, can be set. The optical receiver ( | 07-08-2010 |
20100178062 | RZ-DPSK MODULATED OPTICAL SIGNAL GENERATION APPARATUS AND METHOD - The present invention discloses a RZ-DPSK modulated optical signal generation apparatus and method, wherein the apparatus comprises: a high speed multiplexer for amplifying a photo-electric converted high speed data signal and de-multiplexing it into parallel low speed signals, pre-coding the parallel low speed signals, then multiplexing the pre-coded low speed signals into a high speed data signal, inputting a processed data + and synchronous clock into a first RZ converter and amplifier, and inputting a pre-coded data − and synchronous clock into a second RZ converter and amplifier; a first RZ converter and amplifier and a second RZ converter and amplifier for converting data + and data − NRZ signals into RZ signals, then amplify them separately, and use the amplified RZ signal to drive a LiNbO | 07-15-2010 |
20100226659 | QUANTUM COMMUNICATION APPARATUS, QUANTUM COMMUNICATION SYSTEM AND QUANTUM COMMUNICATION METHOD - The present invention is directed to realize a stable and highly-efficient quantum communication without being influenced by the jitter of the heralding signal. In regard to the quantum encryption transmitting apparatus | 09-09-2010 |
20100278541 | Optical System for Transfer of Timing Reference - The present invention relates to an optical system for transfer of timing reference signal and radio frequency synchronisation of multiple events with femtosecond precision on multiple remote locations such as within a particle accelerator, where synchronisation scheme with a low phase jitter and a long term stability is required using standard telecommunications single-mode optical fibre. Said system comprises a transmitter ( | 11-04-2010 |
20110033191 | METHOD AND DEVICE FOR PHASE RECOVERY AND COMMUNICATION SYSTEM COMPRISING SUCH DEVICE - A method and a device are provided for phase recovery of at least two channels comprising the steps of (i) a phase is estimated for each channel; (ii) the phase estimated of each channel is superimposed by a coupling factor with at least one other phase estimated. Further, a communication system is suggested comprising such a device. | 02-10-2011 |
20110052206 | METHOD, SYSTEM AND OPTICAL NETWORK DEVICE FOR SYNCHRONIZING TIME OF A PASSIVE OPTICAL NETWORK - The present invention relates to optical communications and discloses a master clock time synchronization method, slave clock time synchronization method, system and optical network device in a Passive Optical Network (PON) for the purpose of resolving time synchronization in Ethernet over Gigabit PON Encapsulation Method (GEM) mode. The PON master clock time synchronization method includes: predefining a rule for matching packet time stamp generating points; sending a first clock packet carried in a first downstream frame; acquiring time at a packet time stamp generating point that matches the frame data of the first downstream frame at the PON Media Access Control (MAC) layer and regarding the acquired time as the time the first clock packet is sent; and sending a second clock packet in a second downstream frame, where the second clock packet carries the time the first clock packet is sent. | 03-03-2011 |
20110064420 | PREAMBLE DESIGN FOR SUPPORTING MULTIPLE TOPOLOGIES WITH VISIBLE LIGHT COMMUNICATION - For use in visible light communication (VLC), methods for synchronization with multiple topology support and for transmitting an extended preamble. The method for synchronization includes transmitting a two-part preamble sequence. The preamble sequence includes one or more repetitions of a fast locking pattern (FLP) configured to be used for clock synchronization, and one or more repetitions of a topology dependent pattern (TDP) configured to be used to distinguish a plurality of VLC topologies. The method for transmitting an extended preamble includes generating an extended preamble and transmitting the extended preamble during a receive or idle mode for maintaining visibility support and for better synchronization performance. | 03-17-2011 |
20110097090 | NODE, DATA PROCESSING SYSTEM, AND DATA PROCESSING METHOD - A node, a data processing system, and a data processing method are provided. The node includes a control module, adapted to generate synchronization information and Optical Burst (OB) configuration information; at least one synchronization processing module, adapted to perform a synchronization process on OB paths at a plurality of wavelengths according to the synchronization information; and a cross-connection module, adapted to perform, a cross-connection process on the OB paths, on which the synchronization process has been performed. The data processing system includes at least two nodes, where the nodes are connected through OB paths at one or more wavelengths, and the nodes are adapted to transfer service data through the OB paths. The technical solutions can reduce volume, power consumption, and costs of the nodes, and avoid a problem of generation of data conflict on an optical layer due to lack of optical buffers in all optical switching. | 04-28-2011 |
20110123200 | LOW JITTER RF DISTRIBUTION SYSTEM - A timing signal distribution system includes an optical frequency stabilized laser signal amplitude modulated at an rf frequency. A transmitter box transmits a first portion of the laser signal and receive a modified optical signal, and outputs a second portion of the laser signal and a portion of the modified optical signal. A first optical fiber carries the first laser signal portion and the modified optical signal, and a second optical fiber carries the second portion of the laser signal and the returned modified optical signal. A receiver box receives the first laser signal portion, shifts the frequency of the first laser signal portion outputs the modified optical signal, and outputs an electrical signal on the basis of the laser signal. A detector at the end of the second optical fiber outputs a signal based on the modified optical signal. An optical delay sensing circuit outputs a data signal based on the detected modified optical signal. An rf phase detect and correct signal circuit outputs a signal corresponding to a phase stabilized rf signal based on the data signal and the frequency received from the receiver box. | 05-26-2011 |
20110150499 | System, Method, and Computer Program Product for Fiber Access - A system, method, and computer program product for synchronizing time between a centralized controller device and at least one subscriber device on a fiber access network. The control layer of a network device is expanded, and additional messaging control is added via the transmission of data frames. The expansion prevents reliance on a physical layer signal. The time synchronization also allows a time stamp to be incorporated into a message. Thus, bandwidth is not wasted by simply transmitting a time stamp by itself. In an embodiment, the centralized controller device measures the time difference between the time at which a particular ranging request is transmitted and the time at which the particular ranging request is received. The time difference represents the time adjustment value for the particular subscriber device and allows the device to synchronize its time with that of the centralized controller device. | 06-23-2011 |
20110188864 | OPTICAL TRANSMITTER, OPTICAL RECEIVER, AND OPTICALLY COUPLED INSULATING DEVICE - According to one embodiment, an optically coupled insulating device includes an optical transmitter and an optical receiver. The optical transmitter includes an analog-to-digital converter, an encoder, a transmitting controller, and an electrooptical transducer. The encoder is configured to generate a transmitting signal by superimposing an output of the analog-to-digital converter onto a signal based on a clock signal. The transmitting signal is encoded to have an average duty ratio of more than zero and less than one. The transmitting controller is configured to output one of the transmitting signal and the output of the analog-to-digital converter depending on an input level of the analog signal. The electrooptical transducer is configured to convert an output of the transmitting controller into an optical signal. The optical receiver includes an optoelectrical transducer, a decoder, and a receiving controller. | 08-04-2011 |
20110280585 | OPTICAL PULSE AMPLICATION APPARATUS AND METHOD - A method and apparatus for producing a series of amplified optical pulses from a series of input optical pulses. The method includes creating a set of local optical pulses from a series of input optical pulses, the set of local optical pulses being applied to the input of an optical amplifier and having different amplitudes arranged in a graded order. The set of local optical pulses are amplified by an optical amplifier to have a significantly amplified first local optical pulse that is removed from the set of local optical pulses and output as a part of the series of amplified optical pulses. After removing the significantly amplified first local optical pulse, the set of local optical pulses is recreated by adding a new optical pulse from the series of input optical pulses to the end of the set of local optical pulses; and the recreated set of local optical pulses is routed back to be applied to the input of the optical amplifier to continue producing the series of amplified optical pulses. The formed set of local optical pulses having different (graded) amplitudes arranged in a descending order is configured such that the first local optical pulse has a much higher peak power before the optical amplifier gets saturated. | 11-17-2011 |
20110293288 | OPTICAL LINE TERMINAL, OPTICAL NETWORK UNIT, OPTICAL COMMUNICATION SYSTEM, ERROR CORRECTION METHOD, AND RECORDING MEDIUM - In conventional technology, if a frame itself is discarded as being invalid when a sync header has an error, an error correction cannot be performed on a frame that does not fall out of synchronization even at such a low error rate that an error correction can satisfactorily be performed. According to the present invention, each of an optical line terminal and an optical network unit includes a synchronization detection part for detecting whether or not received data converted into frame form falls out of synchronization, and an error correction part for performing an error correction on a frame of the received data that has been detected not falling out of synchronization by the synchronization detection means, irrespective of existence of an error in a sync header of that frame. | 12-01-2011 |
20110318017 | METHOD, SYSTEM, AND APPARATUS FOR CARRIER SYNCHRONIZATION OF QAM MODULATED SIGNALS - Consistent with the present disclosure, optical signals are modulated in accordance with a higher order QAM modulation format, such as 8-QAM, to carry customer data, for example. The optical signals are converted to corresponding electrical signals, which are then subject to further processing. In particular, phase data associated with the higher order QAM constellation is processed, such that the outer points of the constellation are rotated to have the same phase as the inner points. As a result, both the inner and outer points resemble a constellation, and both may be more readily processed using feedforward or feedback carrier recovery. After such carrier recovery, the phase data is further processed so that the outer points are rotated back and the customer data can be extracted from the phase data. | 12-29-2011 |
20110318018 | METHOD AND RECEIVING DEVICE FOR DETERMINING THE ASSIGNMENT OF SUBSIGNALS TRANSMITTED BY INVERSE MULTIPLEXING, PARTICULARLY VIA AN OPTICAL TRANSPORT NETWORK (OTN), TO THE TRANSMISSION LINKS CARRYING SAID SUBSIGNALS - The invention pertains to a method for determining the assignment of subsignals (S | 12-29-2011 |
20120106976 | 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. | 05-03-2012 |
20130064555 | COMMUNICATION SYSTEM, FRAME SYNCHRONIZATION DETECTION APPARATUS, AND FRAME SYNCHRONIZATION DETECTION METHOD - A frame transmitting unit divides a payload area of an upper-layer frame into a plurality of slots, maps a lower-layer frame to one or more of the slots, and transmits the upper-layer frame including connection information that indicates which one or more of the slots the lower-layer frame of a same type is mapped to. The frame synchronization detection unit identifies, as one or more allocated slots, the one or more slots to which the lower-layer frame of the same type is mapped, on the basis of the connection information, and detects the frame synchronization by identifying a frame head signal of the lower-layer frame of the same type that is mapped to the one or more allocated slots. | 03-14-2013 |
20130272717 | TRANSMISSION SYSTEM, TRANSMITTER AND RECEIVER - According to one embodiment, a transmission system includes a transmitter and a receiver. The transmitter includes a modulator configured to modulate transmission data at a chip rate to generate a modulation signal, and one or a plurality of light sources configured to emit visible light according to the modulation signal. The receiver includes a light receiver having one or more lines of light receiving elements to receive light in a first range including the visible light; and a demodulator configured to demodulate image data generated according to the light received by the light receiver to generate reception data corresponding to the transmission data. A following equation is satisfied ff10-17-2013 | |
20130315606 | DISTRIBUTING CLOCK SYNCHRONIZATION INFORMATION WITHIN AN OPTICAL COMMUNICATIONS NETWORK - A method and system of distributing clock synchronization information within an optical communications network including a plurality of network elements, in which a first network element receives an ingress clock synchronization message, the ingress clock synchronization message including a clock synchronisation message identifier and a correction field. The first network element inserts the clock synchronisation message identifier into an optical channel frame overhead and inserts the ingress clock synchronisation message into an optical channel frame payload. The first network element transmits the optical channel frame overhead and the optical channel frame payload to a second network element, and determines a transit time of the clock synchronisation message identifier across each of the network elements. The second network element updates the correction field of the ingress clock synchronisation message with said transit times to form an egress clock synchronisation message. | 11-28-2013 |
20140064742 | EVENT SYNCHRONIZATION FOR OPTICAL SIGNALS - A system for synchronizing an optical signal with an initiation of an event can include an event controller which controls the initiation of the event, and an optical modulator which modulates the optical signal in response to receipt of an indication from the event controller that the event is initiated. A method of synchronizing an optical signal with an initiation of an event can include transmitting from an event controller an indication that the event is initiated, receiving the indication that the event is initiated, and modulating the optical signal in response to the receiving. A system for synchronizing multiple optical signals can include at least one time-code generator which generates time-codes, and multiple optical modulators which modulate the respective optical signals in response to generation of the time-codes by the at least one time-code generator. | 03-06-2014 |
20140079409 | METHODS OF TIME SYCHRONISATION IN COMMUNICATIONS NETWORKS - A method 10 of providing a path delay asymmetry for time synchronization between a master clock at a first client node and a slave clock at a second client node across a server communications network. The method comprises: mapping a first time protocol signal (TPS) carrying master clock time protocol data onto a first transmission signal, determining a forward mapping delay, d | 03-20-2014 |
20140193161 | Enabling Communication Between Two End Terminals in a Fibre Optic Network - A first end terminal and a second end terminal, as well as a respective method therein, are provided for enabling communication between the first end terminal and the second end terminal in a fibre optic access network. When the first and the second end terminal wish to communicate with each other, they first initiate a synchronisation procedure with the other end terminal for synchronising the two terminals with each other and enabling them to start a negotiation procedure. Then they perform the negotiation procedure, which pertains to a transmission rate for communication on the fibre link between the two end terminals, and they execute communication to the other end terminal employing the negotiated transmission rate. | 07-10-2014 |
20140270804 | CONTROL TIMING SYNCHRONIZATION METHOD, OPTICAL TRANSMISSION SYSTEM, AND OPTICAL TRANSMISSION APPARATUS - A control timing synchronization method is executed by a first and a second optical transmission apparatus. The first optical transmission apparatus: superimposes on a main signal and transmits, information of control process details; waits for a first period; subsequently, superimposes on the main signal and transmits, a message giving notification of control start timing; waits for a second period; and subsequently switches a process of the first optical transmission apparatus to a process corresponding to the control process details. The second optical transmission apparatus: acquires the information on the main signal; waits until detection of the message on the main signal, when a process is present that is to be executed by the second optical transmission apparatus based on the information; waits for the second period when the message is detected while waiting for the detection of the message; and subsequently, executes a process corresponding to the information. | 09-18-2014 |
20140321862 | PHOTON DETECTOR AND A PHOTON DETECTION METHOD - A photon detection system is provided comprising a photon detector, configured to detect photons during intervals when in a receiving state and to output a signal when a photon is received, a controller, configured to generate a time varying gating signal wherein said gating signal switches said detector between the receiving state and a non-receiving state, said controller being configured to receive and process information relating to the times photons are expected to arrive at said detector, the controller being configured to generate the gating signal such that the photon detector is in the receiving state for intervals when photons are expected and also in the receiving state for additional intervals between the intervals when the photons are expected; a detection module, configured to distinguish between when the output signal from the photon detector corresponds to an interval when photons are expected and said additional intervals. | 10-30-2014 |
20150063825 | SIGNAL SYNCHRONIZATION TRANSMISSION SYSTEM, SYNCHRONIZATION DRIVE SYSTEM FOR OPTICAL MODULATOR, SIGNAL SYNCHRONIZATION TRANSMISSION METHOD, AND NON-TRANSITORY COMPUTER READABLE MEDIUM STORING PROGRAM THEREOF - The present invention includes optical phase modulation circuits ( | 03-05-2015 |
20150132012 | TRANSMISSION APPARATUS - A transmission apparatus includes: a plurality of logical lanes; a receiver configured to receive a signal including synchronization information of a frame; a distributor configured to divide data included in the received signal into frame elements and cause the plurality of logical lanes to store the data; and a transmitter configured to transmit the data stored in the logical lanes to lines corresponding to the logical lanes. When the data is stored in the plurality of logical lanes, the distributor groups the logical lanes into a plurality of groups and associates the frame elements with the synchronization information. | 05-14-2015 |
20150139663 | DISTRIBUTING CLOCK SYNCHRONIZATION INORMATION WITHIN AN OPTICAL COMMUNICATIONS NETWORK - A method distributes clock synchronization information within an optical communications network having a plurality of network elements. The method receives an ingress clock synchronization message at a first said network element. The ingress clock synchronization message includes a clock synchronisation message identifier and a correction field. The clock synchronisation message identifier is inserted into an optical channel frame overhead and the ingress clock synchronisation message is inserted into an optical channel frame payload. The optical channel frame overhead and the optical channel frame payload are transmitted across the first network element, across the network to a second said network element, and across the second network element. A transit time of the clock synchronisation message identifier is determined across each of the network elements. At the second network element, the correction field of the ingress clock synchronisation message is updated with said transit times to form an egress clock synchronisation message. | 05-21-2015 |
20150139664 | METHOD AND APPARATUS FOR TIME SYNCHRONIZATION BETWEEN NODES - A method and apparatus for time synchronization between a plurality of nodes in a network. The apparatus distinguishes between an optical synchronization signal for synchronization between nodes and an optical data signal for data transmission, and synchronizes nodes with each other using the optical synchronization signal. | 05-21-2015 |
398155000 | Clock recovery | 22 |
20080199186 | Optical Receiver - A receiver for a differentially phase shift keying formatted optical signal, such as an RZ-DPSK formatted optical signal. Dither control loops are provided for controlling path length in a demodulator and/or for controlling the center wavelength of an optical band pass filter. A feedback loop is provided for controlling the gain of a pre-amplifier, and a method of protecting against optical transients by disabling a pre-amplifier is also provided. A preset delay may be provided to compensate for the differential delay in paths associated with the demodulator arms. When the signal is an RZ-DPSK modulated signal, a clock for retiming data from the optical signal may be derived from a signal on the data path. | 08-21-2008 |
20080205901 | METHOD AND APPARATUS FOR DWDM LINE CARD - A system and method for multiple-channel line card. The system includes a first photonic integrated device configured to receive a first optical signal and output a first plurality of electrical signals for a first plurality of channels respectively. The first plurality of channels corresponds to a first plurality of wavelength ranges associated with the first optical signal. Additionally, the system includes a first clock and recovery device configured to receive the first plurality of electric signals and retime the first plurality of electric signals, and a first switch coupled to the first clock and recovery device, a first interface, and a second interface. Moreover, the system includes the first interface configured to output a second plurality of electrical signals to another system for multiple-channel line card, and the second interface configured to couple with one or more plugged first channel devices. | 08-28-2008 |
20090003835 | Optical clock recovery apparatus and method and birefringent medium - An optical clock signal recovery apparatus includes a mode-locked semiconductor laser that generates an optical pulse train polarized in a first direction. Optical components of the apparatus transmit a component of an input optical signal polarized in a second direction, perpendicular to the first direction, into the mode-locked semiconductor laser while blocking the component of the input optical signal polarized in the first direction, and transmit light exiting the mode-locked semiconductor laser polarized in the first direction, while blocking light exiting the mode-locked semiconductor laser polarized in the second direction. The transmitted exiting light is output as a recovered optical clock signal. | 01-01-2009 |
20090016738 | COMPACT ALL-OPTICAL CLOCK RECOVERY DEVICE - A clock recovery device adapted to recover at least one clock signal from an optical input signal. The input signal includes at least one data signal. The clock recovery device-includes a first waveguide, a first optical resonator coupled to the first waveguide, a second optical resonator coupled to the first waveguide, and a combiner to combine signals provided by the first optical resonator and the second optical resonator in order to provide an output signal. A passband of the first optical resonator is matched with a first spectral peak of the input signal, and a passband of the second optical resonator is matched with a second spectral peak of the input signal such that the spectral separation between the first and the second peaks is equal to a clock frequency associated with a first data signal. The optical resonators store optical energy and provide an output also when the data signal is zero. Thus, the output signal includes a first recovered clock signal which exhibits continuous beat at the first clock frequency. The optical resonators are coupled to the same waveguide by evanescent coupling. A high coupling efficiency may be achieved and the use of further optical splitters may be avoided. | 01-15-2009 |
20090060525 | ALL-OPTICAL POLARIZATION-INDEPENDENT CLOCK RECOVERY - Simultaneous recovery of several different clock signals is based on coupling an optical input signal into an optical resonator matched with at least four spectral peaks of the input signal. The input signal having arbitrary polarization is divided by a polarizing splitter into a first signal having horizontal polarization and a second signal having vertical polarization. The polarization of the first signal is rotated 90 degrees such that the polarization of the first signal is parallel to the vertical polarization second signal. Both vertically polarized signals are passed through the same optical resonator in opposite directions, and they are combined after passing through the resonator in order to form an output signal. The spectral separation between the first peak and the second peak is equal to a first clock frequency, and the spectral separation between the third peak and the fourth peak is equal to a second clock frequency. The resonator stores optical energy and provides an output also when the input signal is zero. Thus, the output signal includes a first recovered clock signal which exhibits continuous beat at the first clock frequency, and a second recovered clock signal which exhibits continuous beat at the first clock frequency. Only vertically polarized light is passed through the resonator. Thus, variations in the polarization of the input signal do not require continuous re-adjustment of the resonator. | 03-05-2009 |
20090154937 | APPARATUS FOR RESTORING CLOCK SIGNAL BY USING CIRCULATOR - Provided is an apparatus and method for restoring clock signals by using a circulator in an optical transmission system. The apparatus includes a circulator, which allows one of N types of input data signals having different transmission speeds to circulate in a single direction, band pass filters, which extract N types of clock frequency components respectively corresponding to each transmission speed of the N types of input data signals, and clock amplifiers, which amplify each of the N types of clock frequency components. | 06-18-2009 |
20090297165 | Optical transmitting apparatus and optical communication system - A waveform converting unit gives a change to a clock signal as a periodic voltage fluctuation that drives a pulse carver unit carrying out shaping into an RZ waveform. The pulse carver unit receives a bias voltage applied thereto from a bias voltage applying unit, is driven by the clock signal that is given a change by the waveform converting unit and that is amplified by an amplifying unit, and outputs an RZ pulse whose duty has been changed. | 12-03-2009 |
20090324245 | OPTICAL TRIGGERED SELF-TIMED CLOCK GENERATION - A self-timed clock circuit and method of generating a self-timed clock circuit. The circuit includes means for charging a circuit node in response to an external reset signal; means for discharging the circuit node in response to a trigger signal generated by a photodiode; means for generating a first signal indicating a logic level of the circuit node; means for generating and delaying a second signal indicating the logic state of the circuit node; means for combining the first and second signals to generate a recharge signal; and means for recharging the circuit node in response to the recharge signal. | 12-31-2009 |
20100046959 | Phase Lock Loop Control For Digital Communication Systems - An optical receiver includes an optical detector that is positioned to detect an optical data signal received from an optical channel generates a received electrical data signal at an output. An electrical switch passes one of the received electrical data signal and a second electrical signal depending upon a control signal applied to a control input. A data and clock recovery circuit generates a recovered clock and a recovered data signal when a signal-to-noise ratio of the received electrical signal is in a range where a signal locking condition is established, and generates the control signal at the control output that instructs the electrical switch to select the received electrical data signal if the signal locking condition is established and to select the second electrical signal if the signal locking condition is not established. | 02-25-2010 |
20100086313 | Optical Signal Phase Regenerator for Formats of Differential Modulation with Phase Changes - The invention relates to a device for regenerating the phase of an optically modulated signal with phase changes and based on two and three replicas, wherein the replicas refer to the number of identical signals that are obtained form the input signal. This regenerator is capable of regenerating the phase and period of any format of modulation of optical communications systems which are differential modulation with phase changes, such as: DISK, DQPSK, RZ-DQPSK, RZ-DQPSK, D8PSK, D8PSK, RZ-D16PSK, D16PSK. The regenerator design presented involves the regenerator being placed alter the multiplexer of a communications system and before the signal modulators and/or decoders. Thus the regenerator receives the signal leaving the multiplexer and this signal is input in an amplitude modulator. | 04-08-2010 |
20100098433 | SYNCHRONIZATION TRANSPORT OVER PASSIVE OPTICAL NETWORKS - One embodiment provides an Ethernet Passive Optical Network (EPON) system for clock transport. The system includes a reference clock configured to generate a frequency-reference signal, an optical line terminal (OLT) coupled to the reference clock, and an optical network unit (ONU). The OLT includes a clock generator configured to generate an OLT clock based on at least the frequency-reference signal. The ONU includes an optical transceiver, a clock recovery module, and a clock output mechanism. The optical transceiver is configured to transmit optical signals to and receive optical signals from the OLT. The clock-recovery module is configured to recover the frequency-reference signal from the received optical signals. The clock output mechanism is configured to output the recovered frequency-reference signal, thus facilitating transport of the frequency-reference signal over the EPON. | 04-22-2010 |
20100166434 | SUBSCRIBER LINE INTERFACE CIRCUITRY WITH INTEGRATED SERIAL INTERFACES - Methods and apparatus for communicating include communicating frames of data at a frequency f | 07-01-2010 |
20110002695 | APPARATUS AND METHOD FOR TRANSMITTING AND RECEIVING DATA USING VISIBLE LIGHT COMMUNICATION - Provided is an apparatus and method for transmitting and receiving data in a visible light communication system, the apparatus including a visible light communication (VLC) transceiver for converting a visible light signal received from a counterpart into an electrical signal and outputting the electrical signal, by using a light receiving device during a reception operation, and converting an electrical signal containing information into a visible light signal and transmitting the visible light signal to the counterpart, by using a light emitting device during a transmission operation, a VLC controller comprising a visible frame engine (VFE) for generating a visible frame and outputting the visible frame to the VLC transceiver, in which the VFE generates the visible frame for transmission to a counterpart during non-transmission of respective frames for communication at a sender and a receiver in order to provide visibility to a communication link, and a host controller for controlling the VLC controller and transmitting and receiving data to and from the VLC controller. | 01-06-2011 |
20110008055 | Combined Burst Mode Level and Clock Recovery - An apparatus comprising an optical receiver configured to receive an optical signal, and a combined level and clock recovery circuit coupled to the optical receiver and configured to update a signal threshold and a clock phase substantially simultaneously. Also included is an apparatus comprising at least one processor configured to implement a method comprising recognizing reception of a signal, and adjusting a threshold and a clock phase associated with the signal using a rising time for the signal and a falling time for the signal. Also included is a method comprising receiving a signal, and adjusting a threshold level of the signal to establish level recovery using a clock recovery scheme. | 01-13-2011 |
20110268457 | METHOD AND APPARATUS FOR OPTICAL SIGNALING - A method and apparatus for optical signaling. In one embodiment, a laser driver converts a digital voltage sequence to a current signal having a bias mode adjustable by a bias control and a modulation mode adjustable by a modulation control. A laser generates an optical signal responsive to the current signal of the laser driver. In one embodiment, a photo-detector receives an optical signal and generates a single ended current signal. A transimpedance amplifier circuit converts the single ended current signal to a differential voltage signal. A clock recovery circuit generates an aligned clock signal and a sampler circuit uses the aligned clock signal to retrieve a digital voltage sequence. | 11-03-2011 |
20120128372 | OPTICAL LINE TERMINATION, PON SYSTEM, AND DATA RECEPTION PROCESSING METHOD - An optical line termination includes a deserializer that parallelizes burst data received from a termination device, a fixed-pattern generating unit that generates fixed pattern data that is a predetermined fixed data, and a data selecting unit that selects either the fixed pattern data or the burst data based on a data-head instruction signal indicating a head of the burst data and a data-end instruction signal indicating an end of the burst data, and inputs the selected data to a deserializer as data to be parallelized. | 05-24-2012 |
20120294625 | COMMUNICATION SYSTEM AND METHOD - A communication system comprising an emitter of weak light pulses, a detector which is capable of detecting single photons, and a source of a clock signal, wherein said emitter and detector are synchronised using said clock signal, the system further comprising a frequency divider for said clock signal to produce a reduced frequency clock signal and a clock regenerator for regenerating the original clock signal from the reduced frequency clock signal, the system further comprising a communication channel configured to communicate the clock signal between the emitter and detector, the clock signal being reduced before sending through said channel and reconstructed after it has exited said channel. | 11-22-2012 |
20130121705 | METHOD FOR DISTRIBUTING TIME WITHIN SYNCHRONOUS ETHERNET AND SONET/SDH DOMAINS - The embodiments of the present invention pertaining to a method for distributing time between a first and a second Synchronous Ethernet “SyncE” domain, said first and second domains being interconnected by a third, Synchronous Optical Networking/Synchronous Digital Hierarchy “SDH-SONET” domain in which a time-associated reference parameter is distributed, through Synchronous Ethernet “SyncE” domains, by means of at least one additional Type Length Value “TLV” field of an Ethernet Synchronization Messaging Channel “ESMC” message and a corresponding time-associated reference parameter is distributed, through the Synchronous Optical Networking/Synchronous Digital Hierarchy “SONET-SDH” domain by means of at least one additional Type Length Value “TLV” field within a message of the IEEE 1588 V2 protocol. | 05-16-2013 |
20140105614 | METHOD AND APPARATUS FOR RECEIVING BURST DATA WITHOUT USING EXTERNAL DETECTION SIGNAL - Apparatus and method for receiving burst data signal without using external detection signal are disclosed. The apparatus can include a clock data recovery (CDR) circuit to generate a clock signal, and a detection circuit to detect an initial portion in the data recovered from the input signal. The CDR circuit can have a first mode that attempts to synchronize the clock signal with a reference data signal, and a second mode that attempts to synchronize the clock signal with the burst data signal and to recover data based on the clock signal. The apparatus can include a controller to conduct a process including, in sequence, setting the CDR circuit in the first mode, setting the CDR circuit in the second mode, and keeping the CDR circuit in the second mode when the detection circuit detects the initial portion in the recovered data. | 04-17-2014 |
20140270805 | Asymmetry Correction for Precise Clock Synchronization Over Optical Fiber - A clock at a first network element that is connected to a second network element over an optical fiber link is aligned in time/phase using packet protocols such as PTP. The invention discloses how to correct the asymmetry error inherent in traditional packet-based time-transfer methods. | 09-18-2014 |
20150110501 | DIRECT-COUPLED DRIVER FOR MACH-ZEHNDER OPTICAL MODULATORS - An optical modulator device directly-coupled to a driver circuit device. The optical modulator device can include a transmission line electrically coupled to an internal VDD, a first electrode electrically coupled to the transmission line, a second electrode electrically coupled to the first electrode and the transmission line. A wave guide can be operably coupled to the first and second electrodes, and a driver circuit device can be directly coupled to the transmission line and the first and second electrodes. This optical modulator and the driver circuit device can be configured without back termination. | 04-23-2015 |
20160065316 | SIGNAL RECOVERY CIRCUIT AND SIGNAL RECOVERY METHOD - A signal recovery circuit includes: a data acquisition circuit configured to collect a received data signal according to a transition edge of a received signal recovery clock; and a phase adjustment circuit configured to adjust a phase relationship between the transition edge of the received signal recovery clock and the received data signal according to a data value of the received data signal to be acquired by the data acquisition circuit. | 03-03-2016 |