Abstract: 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 synchronization message identifier and a correction field. The first network element inserts the clock synchronization message identifier into an optical channel frame overhead and inserts the ingress clock synchronization 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 synchronization message identifier across each of the network elements. The second network element updates the correction field of the ingress clock synchronization message with said transit times to form an egress clock synchronization message.

Abstract: 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.

Abstract: A time synchronization method and a time synchronization device in a passive optical network (PON), and a PON are provided. The method includes receiving a synchronization packet sent after time synchronization of an optical line terminal (OLT) with a master clock (MC) is achieved, wherein the synchronization packet carries a timestamp TMt1i determined after the time synchronization of the OLT is achieved, adjusting a local clock according to the timestamp to achieve time synchronization of an optical network unit/optical network terminal (ONU/ONT) with the OLT, and after the time synchronization of the OLT is achieved, instructing an slave clock (SC) to perform time synchronization. A time synchronization device and a time synchronization system for implementing the method in a PON are further provided.

Abstract: One embodiment provides an EPON for transporting RF signals. The system includes a reference clock, an ONU, and an OLT. The ONU includes a mechanism for receiving a frequency and phase-reference signal from the OLT, a mechanism for receiving an RF signal, an ADC for converting the RF signal into a digital signal using a sampling signal associated with the frequency and phase-reference signal, a mechanism for assembling at least a portion of the digital signal into a packet, a mechanism configured to timestamp the packet, and an optical transceiver. The OLT includes a mechanism for receiving the packet, a buffer, a delay mechanism configured to delay reading the received packet from the buffer for a predetermined amount of time, and a DAC for converting the digital signal included in the packet back to RF domain using a clock signal associated with the frequency and phase-reference signal.

Abstract: An apparatus comprising a data framer configured to frame a data stream into a plurality of frames each comprising a plurality of fields sized to align the frames with a word boundary greater than or equal to about four bytes long, and an optical transmitter coupled to the data framer and configured to transmit the frames. Included is an apparatus comprising at least one component configured to implement a method comprising encapsulating a data stream with at least one Gigabit Passive Optical Network (GPON) Encapsulation Method (GEM) payload aligned with a word boundary at least about four bytes long, encapsulating the GEM payload with a GPON Transmission Convergence (GTC) frame aligned with the word boundary, and transmitting the GTC frame.

Abstract: 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.

Abstract: In a communication line switching method for an optical communications system in which a station-side line terminal apparatus and user-side line terminal apparatuses are connected via a plurality of redundant physical lines, the discovery of the station-side optical line terminal registering the user-side line terminal apparatuses, wherein the registered user-side line terminal apparatuses monitoring a time stamp drift error that is generated when a difference between a time stamp included in a received signal and a local time measured by the own apparatus is larger than a value set in advance and, when the time stamp drift error occurs, shifting to a deregistered state and waiting for registration by the discovery. The station-side line terminal apparatus switches a physical line from a working physical line to a backup physical line of the physical lines.

Abstract: A method may include receiving a stream of datagrams, the datagrams having a first bit length. The method may also include selecting a block of bits from consecutively-received datagrams, the block having a second bit length greater than the first bit length. The method may additionally include determining whether a particular data field is present at a particular bit position within the block. The method may further include outputting the block as a valid block in response to determining that the particular data field is present at the particular bit position. The method may additionally include, in response to determining that the particular data field is not present at the particular bit position: discarding a received datagram from the stream of datagrams; and repeating the receiving, selecting, determining, and discarding steps until a determination is made that the particular data field is present at the particular bit position.

Abstract: A burst transmission method and a receiver resetting method and apparatus in a Passive Optical Network (PON) are provided. A burst receiver resetting method in a PON includes: receiving a preamble sequence and synchronizing data; after synchronizing the data, continuing to receive the data, and matching a Burst Terminator (BT); and resetting a receiver after successfully matching the BT. Meanwhile, an apparatus for implementing the method and a corresponding burst data transmission method are provided. By using the burst receiver resetting method and apparatus in the PON and the corresponding burst transmission method at an Optical Network Unit (ONU) burst transmission end, a Reach Extender (RE) does not need to unpack upstream burst bandwidth allocation information carried in downstream data.

Abstract: An optical measurement instrument comprises operational modules (101-107) that are interconnected via a digital communication network (110). Each operational module comprises a transceiver (111-117) connected to the digital communication network and arranged to support a pre-determined digital communication protocol employed in the digital communication network. Those operational modules that include a detector further comprise an analog-to-digital converter (118) for converting a detected signal into a digital form and a digital circuitry (119) for providing digital information based on the detected signal with address data related to a particular operational module to which the digital information is to be delivered via the digital communication network.

Abstract: In a communication line switching method for an optical communications system in which a station-side line terminal apparatus and user-side line terminal apparatuses are connected via a plurality of redundant physical lines, the discovery of the station-side optical line terminal registering the user-side line terminal apparatuses, wherein the registered user-side line terminal apparatuses monitoring a time stamp drift error that is generated when a difference between a time stamp included in a received signal and a local time measured by the own apparatus is larger than a value set in advance and, when the time stamp drift error occurs, shifting to a deregistered state and waiting for registration by the discovery. The station-side line terminal apparatus switches a physical line from a working physical line to a backup physical line of the physical lines.

Abstract: An output control unit outputs data of bit rate A to a first header-attaching unit and data of bit rate B to a second header-attaching unit. An instructing unit instructs the first or the second header-attaching unit to attach a header of bit rate being the least bit rate to the data of bit rate A or B. The first header-attaching unit creates a header of bit rate A, including an ID of a destination ONU of the data of bit rate A and information concerning the data length, and attaches the header of bit rate A to the data of bit rate A. The second header-attaching unit creates a header of bit rate A, including an ID of the destination ONU of the data of bit rate B and information concerning the data length, and attaches the header of bit rate A to the data of bit rate B.

Abstract: The present invention discloses a method and system for accurate time transfer in PON. An Optical Line Terminal (OLT) ranges Optical Network Units (ONUs) and obtains ranging information, then, triggered by the periodic Pulse per n Second (PPnS), generates a PPnS timestamp based on the local reference counter and the Time of Day (TOD) above second; OLT transmits the ranging information, the periodic PPnS timestamp and TOD to ONUs; ONUs predicts the time of the next second according to said periodic PPnS timestamp, TOD and ranging information, and outputs the corresponding PPnS. The invention is characterized by the combination of the features of PON point to multi-point and PON ranging into its time transfer method, the high accuracy of time transfer, and the low hardware costs for OLT and ONU, as well as the extremely small bandwidth occupancy.

Abstract: Provided is a passive optical network system for operating a mixture of PONs with differing transmission speeds and is capable of reducing power consumption on the basis of the amount of signals being transmitted. The master station of the passive optical network system, which determines the amount and timing of signals sent thereto by each of a plurality of slave stations on the basis of the requests of the plurality of slave stations and receives signals from the plurality of slave stations via an optical fiber network, is equipped with a control unit that determines in each set cycle the amount, transmission timing, and transmission speed of the signals that each slave station is permitted to transmit to said master station on the basis of the amount of signals that each of the plurality of slave stations has requested to transmit, and that notifies such to each slave station.

Abstract: Terminals of upstream and downstream sides of an in-service line and a detour line are connected by optical couplers. An optical oscilloscope is connected to one optical coupler, and a chirped pulse light source is connected to the other optical coupler to thereby form dualized lines. The detour line includes an optical line length adjuster for compensating for the phase difference of optical transmission signals that occurs because of the optical line length difference with the in-service line. Pulse light in which an optical frequency is chirped is transmitted from the chirped pulse light source. The pulse light is branched by the second optical coupler, passes through the in-service line and the detour line, is multiplexed again by the first optical coupler, and is measured by the optical oscilloscope.

Abstract: 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.

Abstract: In a communication system using a PON, time synchronization of a slave device such as a base station is realized with respect to a master device such as an L2SW or the base station. Time information acquired by a GPS satellite is corrected by ranging information of a discovery function of an OLT so as to be reflected on time information of each ONU. A propagation delay from the L2SW to the OLT is obtained with the use of a delay estimation mechanism, a propagation delay from the OLT to the ONU which is obtained by ranging is added to obtain a propagation delay from the L2SW to the ONU. The obtained propagation delay from the L2SW to the ONU is added to the transmitted time stamp value whereby a time stamp value received at a base station or femtocell side becomes a time into which the propagation delay to the ONU is incorporated, and absolute values of clock timers can be synchronized with each other.

Abstract: Aspects of the invention provide transmitters and receivers for managing multiple optical signals. High order modulation, such as phase and/or amplitude modulation, is used to achieve multiple bits per symbol by transporting multiple asynchronous data streams in an optical transport system. One or more supplemental multiplexing techniques such as time division multiplexing, polarization multiplexing and sub-carrier multiplexing may be used in conjunction with the high order modulation processing. This may be done in various combinations to realize a highly spectrally efficient multi-data stream transport mechanism. The system receives a number of asynchronous signals which are unframed and synchronized, and then reframed and tagged prior to the high order modulation. Differential encoding may also be performed. Upon reception of the multiplexed optical signal, the receiver circuitry may employ either direct detection without a local oscillator or coherent detection with a local oscillator.

Abstract: A system and method for data synchronization in Passive Optical Networks are disclosed. 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.

Abstract: The present invention utilizes external synchronization to generate a completely standardized or functionally standardized optical transmission unit of level k (OTUk[V]) signal providing less jitter and wander build-up through a network of optical transport network (OTN) elements. This increases noise margins of transported signals and payloads. The present invention provides stratum-level synchronization utilizing a standards-based approach. In one embodiment of the present invention, rate adapters are included to provide m/n scaling of OTUk[V] signals to rates common in SONET and SDH synchronizers to provide line and loop distribution of timing through OTUk[V] signals. The present invention provides a choice of external synchronization sources including building integrated timing source (BITS), line, and loop timing sources. In another exemplary embodiment, the present invention provides multiple external references and automated timing protection switching for redundancy and reliability.

Abstract: A system, a Laser-on-CMOS chip, and a method are described herein in accordance with the present invention. In one embodiment, the present invention enables a conventional WDM-capable system to dictate what wavelengths a Laser-on-CMOS chip's optical ports will use by seeding each of their LoC upstream reflective light generation devices (e.g., RSOAs) with a particular wavelength.

Abstract: A voltage generator (400) includes a resistor ladder including resistors (4000-4008) which divide a supplied voltage to generate a plurality of reference voltages, a resistor (4009) provided between a power supply voltage (VCC) and one terminal of the resistor ladder, and a resistor (4010) provided between a power supply voltage (VEE) and the other terminal of the resistor ladder.

Abstract: A vector sum phase shifter includes a 90° phase shifter (1) which generates an in-phase signal (VINI) and a quadrature signal (VINQ) from an input signal (VIN), a four-quadrant multiplier (2I) which changes the amplitude of the in-phase signal (VINI) based on a control signal (CI), a four-quadrant multiplier (2Q) which changes the amplitude of the quadrature signal (VINQ) based on a control signal (CQ), a combiner (3) which combines the in-phase signal (VINI) and the quadrature signal (VINQ), and a control circuit (4). The control circuit (4) includes a voltage generator which generates a reference voltage, and a differential amplifier which outputs the difference signal between a control voltage (VC) and the reference voltage as the control signal (CI, CQ). The differential amplifier performs an analog operation of converting the control voltage (VC) into the control signal (CI, CQ) similar to a sine wave or a cosine wave.

Abstract: 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.

Abstract: 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.

Abstract: An optical receiving apparatus with frame synchronization technology which makes it easy to activate a frame synchronization established state even if bit errors are produced over a transmission link. The apparatus includes: an optoelectrical converting circuit; a pre-stage synchronizing word detecting circuit; a decoder; a post-stage frame synchronization detecting circuit; and a receiver frame synchronization display output circuit.

Abstract: A printed circuit board includes a substrate, a signal output circuit formed on the substrate for outputting a clock signal, a shield for covering the signal output circuit, a power supply wiring for connecting the signal output circuit and a power source, and a trap filter provided to the power supply wiring and provided inside the shield, for attenuating a frequency component corresponding to a frequency of clock signal. The trap filter includes a resonance circuit having one portion of the power supply wiring, an inner-layer wiring of the substrate located below the one portion of the power supply wiring, an inner-layer ground wiring of the substrate located below the inner-layer wiring, and a via hole for connecting the one portion of the power supply wiring and the inner-layer wiring.

Abstract: In one embodiment, an optical transmission system transmits data using a format according to which a data frame has two or more pilot-symbol blocks, each having a guard interval, and two or more payload-symbol blocks that are concatenated without a guard interval between them. The use of guard intervals in the pilot-symbol blocks helps the synchronization and channel-estimation procedures performed at a receiver of the optical transmission system to be robust in the presence of certain transmission impairments. The absence of guard intervals in the payload-symbol blocks helps to minimize the transmission overhead and thus achieve relatively high payload-data throughput.

Abstract: An optical receiver, transmitter, transceiver or transponder for bursty, framed or continuous data. The optical receiver includes a burst mode clock recovery module that recovers the clock rapidly and with a small number of preamble or overhead bits at the front end of the data. A local clock is used for timing when the recovered clock is not available. Transitions between the recovered clock and local clock are smoothed out to avoid undesirable artifacts.

Abstract: We demonstrate a novel type of data receiver, which has superior performance compared to a standard receiver when an input signal is distorted by timing jitter. A method and apparatus for improved timing jitter tolerance includes sampling an input signal more than once within a bit slot of the input signal and determining, using logic circuitry, from a combination of at least a subset of the samples, a resulting logic state for an output signal.

Abstract: 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.

Abstract: A method of synchronizing optronic systems, of the type operating simultaneously on one and the same scene, each optronic system being intended to emit and/or receive light of a target of the scene and each optronic system having an internal precision clock and a module suitable for synchronizing the internal clock with a reference time signal, the method being characterized in that it has the following steps of receiving and generating a reference time signal by each synchronization module, the reference time signal being independent of the optronic systems and emanating from an item of equipment different from the optronic systems, and synchronizing the internal clock of each optronic system with the reference time signal by the synchronization module.

Abstract: A method of controlling a timing state of a local oscillator (17) being synchronized by a timing signal (ST1) provided through one-way transmission from a remote master oscillator (6) through a dielectric waveguide (4).

Abstract: A method, bus controller, and computer program product for arbitrating use of a communication bus for a certain one of a plurality of interconnected nodes that share the bus. The method includes the steps of: presenting a data frame on the transmitter and receiver side of the bus, where the certain node presents at the transmitter side, where the data frame has a embedded clock of a predetermined timing and a header field, synchronizing, by the certain node, with the embedded clock in the data frame at the receiving side of the bus, successively presenting, by the certain node, an idle pattern on the bus determined by a preassigned node ID, emitting light, by the certain node, on the bus at a predetermined timing preassigned to the certain node, and monitoring light emission on the bus that indicates a bus access request from another one of the nodes.

Abstract: A clock at a first network element that is connected to a second network element over first and second optical links that are physically distinct from each other is aligned using optical timing signals having different wavelengths. Transit delays between the first and second network elements may be determined using the same optical timing signals.

Abstract: 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.

Abstract: A device may include a first module to capture information relating to network traffic passing through a first interface in a network device. A second module may capture information relating to network traffic passing through a second interface in the network device. A control module may be configured to transmit control commands to the first module and the second module, the control commands instructing the first module and the second module to capture information relating to network traffic passing through the first interface and the second interface, respectively. The control module may be further configured to receive the captured information from the first module and the second module, correlate the received information from the first module and the second module; and provide the correlated information to a user.

Abstract: A burst transmission method and a receiver resetting method and apparatus in a Passive Optical Network (PON) are provided. A burst receiver resetting method in a PON includes: receiving a preamble sequence and synchronizing data; after synchronizing the data, continuing to receive the data, and matching a Burst Terminator (BT); and resetting a receiver after successfully matching the BT. Meanwhile, an apparatus for implementing the method and a corresponding burst data transmission method are provided. By using the burst receiver resetting method and apparatus in the PON and the corresponding burst transmission method at an Optical Network Unit (ONU) burst transmission end, a Reach Extender (RE) does not need to unpack upstream burst bandwidth allocation information carried in downstream data. Therefore, the complexity of the implementation of the RE is reduced, and the method is simple and effective.

Abstract: 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.

Abstract: A system for distributing a reference oscillator signal includes a clock having a reference oscillator and a femtosecond laser stabilized by the reference oscillator. The system also includes at least one beamsplitter configured to split the femtosecond laser. The system further includes one or more remote nodes that are spaced from the clock. The remote nodes are configured to generate reference signals based on the split femtosecond laser.

Abstract: 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 ff<fm where fm is the chip rate, and ff is a frame rate of the light receiver.

Abstract: Herein disclosed a digital image sender for transmitting a digital image signal including image signals for color image reproduction, a reference clock signal and parallel control signals, including: a parallel/serial converter configured to convert the parallel control signals into a serial control signal by time division multiplexing; a superposition element configured to superpose the serial control signal obtained by the conversion by said parallel/serial converter on the reference clock signal and output a resulting superposition signal; and an electro-optic converter configured to convert the superposition signal outputted from said superposition element from an electric signal into an optical signal.

Abstract: A method for synchronizing time by an optical network terminal (ONT) in a passive optical network system is provided. The method includes: receiving a ranging request message including a first current time of an optical line terminal (OLT); calculating a first compensation time when a transmission delay is compensated at a time that the ranging request message is received; transmitting a serial number response message to the OLT; calculating a second compensation time when the transmission delay is compensated at a time when the serial number response message is transmitted; receiving a ranging time message including a second current time when the serial number response message from the OLT is received; calculating an offset time from the first current time, the second current time, the first compensation time, and the second compensation time; and synchronizing a clock of the ONT and a clock of the OLT based on the offset time.

Abstract: Embodiments of the present invention relate to systems and methods for distributing an intentionally skewed optical-clock signal to nodes of a source synchronous computer system. In one system embodiment, a source synchronous system comprises a waveguide, an optical-system clock optically coupled to the waveguide, and a number of nodes optically coupled to the waveguide. The optical-system clock generates and injects a master optical-clock signal into the waveguide. The master optical-clock signal acquiring a skew as it passes between nodes. Each node extracts a portion of the master optical-clock signal and processes optical signals using the portion of the master optical-clock signal having a different skew for the respective extracting node.

Abstract: A method for performing an optical line analysis of continuous data signals transmitted in a passive optical network (PON). The method comprises determining, from an optical signal of the optical line, at least one of a phase early/late indicator based on a phase position of an input continuous data signal relative to sampling clock signals, a difference phase indicator based on an input phase control code, and a low frequency jitter indicator based on an input phase control code; computing a plurality of statistical measures regarding frequency and amplitude components of a jitter of the input continuous data signal, wherein the statistical measures are computed based on one of the phase early/late information indicator, the difference phase indicator, and the low frequency jitter indicator; and analyzing the plurality of statistical measures to detect optical failures in the PON and determining a root cause of each of the detected failures.

Abstract: A PPM transmitter includes an optical clock generator for generating equally-spaced optical pulses with a sampling period T; an encoder for transforming an incoming waveform U(t) into a linear combination V(t) of U(t) and a delayed output V(t?kT) according to a rule V(t)=U(t)+aV(t?kT), where k is a positive integer, V(t) is voltage generated by the encoder and a is a coefficient; and an optical delay generator for delaying optical pulses generated by the optical clock generator in proportion to the voltage V(t), such that ?tn=bV(t), where b is another coefficient and where ?tn is the amount of delay imposed by the optical delay generator. The PPM transmitter functions with a PPM receiver for communicating data without the need to transmit or otherwise provide a clock signal. The PPM receiver decodes an original series of the delayed optical pulses Q(t) and a second series Q(t?ckT) delayed by ckT where c is a coefficient.

Abstract: Systems and methods for visible light communication are disclosed. In part, illumination devices and related systems and methods are disclosed that can be used for general illumination, lighting control systems, or other applications. The illumination devices synchronize preferentially to the AC mains to produce time division multiplexed channels in which control information can be communicated optically by the same light source that is producing illumination. Such illumination devices preferentially comprise LEDs for producing illumination, transmitting data, detecting ambient light, and receiving data, however, other light sources and detectors can be used. The physical layer can be used with a variety of protocols, such as ZigBee, from the Media ACcess (MAC) layer and higher.

Abstract: The invention relates to a method to discover Optical Network Units (ONU) with different speed capabilities in an Ethernet Passive Optical Network (EPON) by an Optical Line Termination (OLT), where logical links in the network are identified by Logical Link IDs, and the OLT can transmit and receive data with 1 Gbit/s-speed (1 G) and 10 Gbit/s-speed (10 G), and the discovery process is handled in the OLT by a Multi Point Control Process (MPCP), which exchanges messages as Data Units (MPCPDU) with the ONUs. This is achieved by extending the standard MPCPDUs in a way, that backward compatability is assured.

Abstract: Signal format conversion apparatus and methods involve converting data signals between a first signal format associated with a first reference clock rate and a second signal format that is different from the first signal format and is associated with a second reference clock rate different from the first reference clock rate. A period of the second signal format is changed to match a period of a third signal format by controlling a synchronized second reference clock rate that is applied in converting data signals between the first signal format and the second signal format. The synchronized second reference clock rate is different from the second reference clock rate and is synchronized with a third reference clock rate. The third reference clock rate is associated with the third signal format. Such synchronization simplifies conversion of signals between the second and third signal formats.

Abstract: A synchronous optical signal generation device includes: an optical phase detector that compares the phase of a reference optical signal with a phase of an optical beat signal to generate a phase error signal; a shaping mechanism that shapes the phase error signal; and a voltage controlled optical signal generator that generates an optical beat signal based on the shaped phase error signal and that outputs the optical beat signal while feeding the optical beat signal back to the phase detector.