Abstract: According to one aspect, the invention relates to a device (20) for synchronizing optical pumping entanglement sources (141, 142) in a quantum communication network, including a pulsed light source (21) enabling the emission of telecom-wavelength light pulses (I1,I2), which are distributed in parallel with all of the entanglement sources in order to provide an optical clock common to said entanglement sources and including, for each entanglement source, a device (243, 253) for converting the frequency of the distributed light pulse, thereby enabling a light pulse to be generated at a wavelength adapted to the optical pumping of the entanglement source in order to generate pairs of entangled photons.

Abstract: An apparatus comprising a wavelength division multiplexer (WDM), an optical network unit (ONU) coupled to the WDM, a passive optical network (PON) data over cable service interface specification (DOCSIS) upstream proxy (PDUP) coupled to the ONU and configured to couple to a coaxial cable, and a downstream (DS) optical/electrical (O/E) converter coupled to the WDM and configured to couple to the coaxial cable. An apparatus comprising a WDM, an optical line terminal (OLT) coupled to the WDM, a cable model termination system (CMTS) coupled to the OLT via an upstream external physical (PHY) interface (UEPI), and a DOCSIS and a Quadrature Amplitude Modulation (QAM) unit coupled to the WDM and the CMTS.

Abstract: A transmitting apparatus includes a first circuit to which a base clock and a first clock condition are input, the first circuit outputting a first enable signal based on the base clock and the first clock condition; a second circuit to which the base clock and a second clock condition are input, the second circuit outputting a second enable signal based on the base clock and the second clock condition; a first frame processing circuit receiving a first frame input signal and the first enable signal to output a first frame output signal in synchronization with the first enable signal; and a second frame processing circuit receiving a second frame input signal and the second enable signal to output a second frame output signal in synchronization with the second enable signal.

Abstract: A wireless communications system including a mobile station MS and base stations BS1 and BS2, wherein one or both of the mobile station MS and the base stations BS1 and BS2 is provided with a unit for notifying information of a frame position with the possibility of transmission of packets based on detection of deterioration of a reception quality and wherein the mobile station MS is provided with a unit for determining a frame position without the possibility of transmission of packets and shifting to a peripheral cell detection mode at this frame position based on information of a frame position with the possibility of transmission of packets, whereby it is possible to shift to a peripheral cell detection mode without lowering the transmission efficiency and without complicating the processing.

Abstract: 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.

Abstract: A method and system for transmitting data over a Jacobi MIMO channel when using channel state feedback.

Abstract: An optical connection infrastructure has optical conduits between first devices and at least one second device. Dynamic reconfiguration of the optical connection infrastructure can be performed from a first connection topology to a second, different connection topology based on programming of the first devices.

Abstract: Optical Transport Network (OTN) High Order (HO) mapping systems and methods utilize pointer processing to map one HO signal into another similarly sized HO signal. An OTN HO mapping method and circuit include receiving a first HO signal at a first rate, asynchronously mapping the first HO signal into a second HO signal at a second rate, wherein the first rate and the second rate are substantially similar, translating a portion of overhead from the first HO signal to overhead of the second HO signal, utilizing pointers in the overhead of the second HO signal for frame alignment of the first HO signal, and transmitting the second HO signal containing the first HO signal.

Abstract: There is provided an optical signal transmitting apparatus included in an optical communication system which performs communication by transmission and reception of an optical signal indicating digital data. The optical signal transmitting apparatus includes a transmission data generating unit configured to set a data length of each frame constituting the optical signal based on a frequency tolerance of a clock signal on a transmission side and a reception side, and generate digital transmission data having multiple consecutive frames of same contents, each frame having the set data length; and a light emission driving unit configured to drive a light emitting unit to output the optical signal indicating the digital transmission data.

Abstract: A method and apparatus conduct an optical clock rate negotiation to support asymmetric clock rates for visible light communication (VLC) in a VLC device. A first frame that includes a receiver clock rate supported by a first VLC device is transmitted at a predetermined clock rate. A response frame that includes a receiver clock rate supported by a second VLC device is received from the second VLC device. A transmission clock rate of the first VLC device is selected based on the response frame from the second VLC device. Subsequent frames for data communication are transmitted to the second VLC device at the selected transmission clock rate of the first device. Alternatively, when conducting optical clock negotiation in the PHY layer, multiple clock rates are supported within a single frame.

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: 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: 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: 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 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 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 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: 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 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: An apparatus and method for extracting an optical clock signal are provided. The apparatus includes a first reflection filter selecting and reflecting only a first frequency component in an input optical signal; a first Fabry-Perot laser diode matching the first frequency component reflected by the first reflection filter with a predetermined output mode and outputting the first frequency component in the predetermined output mode; a second Fabry-Perot laser diode selecting a second frequency component in an input optical signal that has not been reflected but has been transmitted by the first reflection filter, matching the second frequency component with a predetermined output mode, and outputting the second frequency component in the predetermined output mode; and a photodetector receiving the first frequency component from the first Fabry-Perot laser diode and the second frequency component from the second Fabry-Perot laser diode and beating them to extract a clock signal.