Abstract: The discrimination phase margin monitor circuit (10) of the present invention comprises a first discrimination circuit (11 and 12) discriminating an input data signal using a clock signal extracted from the input data signal, a second discrimination circuit (13 and 14) discriminating the input data signal using a clock signal with a frequency different from that of the clock and an operation circuit (15 and 16) calculating the exclusive OR of the output signal of the first discrimination circuit and that of the second discrimination circuit and obtaining a phase margin monitor output signal by averaging the exclusive ORs.

Abstract: A method and apparatus for processing a data signal for transmission to a remote device transmits at least two synchronized copies of the data signal, in optical form, in different directions. To that end, the data signal first is synchronized to a clock signal to produce a composite signal. The composite signal then is converted to an optical signal, which is referred to as an “outgoing signal.” A plurality of copies of the outgoing signal then are transmitted. At least two copies of the outgoing signal are transmitted in different directions.

Abstract: A wireless communications network including multiple nodes, and a local node having GPS-based time for synchronization of time-of-day (TOD) in the network. The network includes at least the local node and a neighbor node communicating in the network. The local node includes a clock generator for generating a local TOD, and a time management unit, coupled to the clock generator, for adjusting the local TOD. A receiver in the local node receives from the neighbor node a message including a neighbor TOD. A counter in the local node computes and provides an integer value corresponding to a number of update values for synchronization of the neighbor TOD to the GPS-based time. A transmitter in the local node transmits to the neighbor node the integer value provided by the counter, whereby the time management unit adjusts the local TOD to the neighbor TOD and then transmits the adjusted local TOD and the integer value to the neighbor node for synchronization of the neighbor TOD to the GPS-based time.

Abstract: An optical transmitter includes a continuous wave optical source for generating an optical signal having a carrier frequency component, a clock modulator for performing a clock modulation upon the optical signal using a clock signal to generate a clock-modulated signal, and a data modulator for performing a data modulation upon the clock-modulated signal using a data signal. The clock signal has a half frequency of that of the data signal. The clock modulator is constructed by a single-end type phase modulator and at least one tap type optical filter.

Abstract: A method and apparatus is provided that yields improved performance of both single channel and WDM long-distance optical transmission systems by synchronously modulating of the transmitted signal's amplitude. An amplitude modulator receives an optical signal onto which data has been modulated at a predetermined frequency. The modulator re-modulates the amplitude of the optical signal in a continuous fashion with a waveform that is periodic, whose fundamental frequency is equal to the same predetermined frequency at which the data is modulated onto the optical signal. The resulting signal (which is neither a pure NRZ or RZ signal) is more tolerant to the distortions usually found in lightwave transmission systems, thus giving superior transmission performance.

Abstract: An optical transmission system accomplishes optical transmission over a long distance by combining a multiplexing line terminal with optical amplifiers, linear repeaters, and regenerators with optical amplifiers combined together. The system also accomplishes the optical transmission over a short distance by directly connecting the linear terminals therebetween, with an electric-to-optic converter replaced by an electric-to-optic converter having a semiconductor amplifier, with an optic-toelectric converter by an optic-to-electric converter having an avalanche photodiode as light receiver, and with no use of any optical booster amplifier and optical preamplifier in multiplexing line terminal. With these, the optical transmission system can be easily constructed depending on the transmission distance required.

Abstract: Telecommunications systems can be synchronized via the transmission link. In this process, the telecommunication systems receive the clock signal and an additional information item, which describes the quality of the clock signal, from the received data stream. In telecommunication systems which are connected to a number of differently standardized transmission networks, different algorithms for evaluating the differently formatted clock signal quality data are necessary in the main processor. The present telecommunication system simplifies the communication of clock signal qualities. The different interface cards have converters which convert the clock signal quality information between a transmission-network-specific format and an independent format. The main processor only contains a subunit for processing all clock signal qualities. The present method for synchronizing a telecommunication system includes a converting the transmission-network-specific data into messages of an independent format.

Abstract: A signal communication apparatus of a clock reproduction system in which clock signals are extracted from each of parallel data signals for redigitizing each of the data signals. The apparatus includes a reference clock signal generating circuit which is comprised of a clock extraction circuit for extracting a clock signal from each of a plurality of bits of received data signals, and a clock signal selection circuit for selecting one of the extracted clock signals. Alternatively, the reference clock signal generating circuit may be comprised of a data signal selection circuit for selecting one of a plurality of received data signals, and a clock extraction circuit for extracting a clock signal from the selected bit. Based on the resultant reference clock signal, clock signals are obtained that are phase-adjusted for redigitizing each bit of the received data signals.

Abstract: An optical binary code transmission system comprising a sender comprising: means for generating a light beam; phase-shifter means; attenuator means whereby the intensity of the lateral modes is sufficiently low for there to exist at the most only one photon in the lateral modes. The phase-shifter means of the sender impose a phase-shift that is chosen randomly to be equal either to 0 or to ?/2 for a first bit value or either to ? or to 3?/2 for a second bit value, and the receiver comprising means for detecting the presence of a photon in the first lateral mode and means for detecting the presence of a photon in the second lateral mode, a first bit value being detected if the presence of a photon is detected in the first lateral mode and a second bit value being detected if the presence of a photon is detected in the second lateral mode.

Abstract: The present invention provides for a system and method for an optical communication system that utilizes an optical modulator as an optical correlator in a receiver. The present invention may be used as a correlator in a receiver for an On-Off Keying (OOK) system or for a Differential Phase Shift Keying (DPSK) system. A correlation modulator is followed by a low pass filter, which together act as a correlator to determine the correlation of the received waveform with possible transmitted waveforms to produce a maximized signal-noise ratio. The result is a high data rate communication system and method that approaches the theoretical performance limit.

Abstract: An optical asynchronous chirp device having an input port and an output port, comprising first and second optical phase modulators optically connected in series between the input port and the output port of the device, a local oscillator connected to the first and second phase modulators, and a phase shifter connected between the local oscillator and one of the phase modulators, and systems and methods related thereto.

Abstract: A method is directed to recovering a digital data content in a communication system, wherein the digital data content has been converted into an analog signal based on a primary clock, at a transmitter for transmitting to a receiver. The method comprises receiving the analog signal by the receiver. The analog signal is converted into a digital signal, based on a clock of the receiver. The digital signal is interpolated at the desired interpolation point, if digital signal in time has been shifted by an amount equal to or larger than a predetermined time length. The interpolated digital signal is recovered back to the digital data content, with the assist of an estimated channel impulse response. The channel impulse response is retrained every time when the interpolation point is significantly changed.

Abstract: The invention relates to the distribution of a synchronization signal in an optical communication system which is inherently asynchronous. In order to accomplish a cost-efficient mechanism for transmitting a synchronization signal in such a system, the amplitude of a payload signal is modulated with the synchronization signal, whereby an amplitude-modulated payload signal is obtained. This amplitude-modulated payload signal is transmitted as an optical signal to the opposite end of an optical link, where the synchronization signal is separated from the payload signal.

Abstract: Processing a received optical signal in an optical communication network includes equalizing a received optical signal to provide an equalized signal, demodulating the equalized signal according to an m-ary modulation format to provide a demodulated signal, decoding the demodulated signal according to an inner code to provide an inner-decoded signal, and decoding the inner-decoded signal according to an outer code. Other aspects include other features such as equalizing an optical channel including storing channel characteristics for the optical channel associated with a client, loading the stored channel characteristics during a waiting period between bursts on the channel, and equalizing a received burst from the client using the loaded channel characteristics.

Abstract: A bit synchronization circuit composed of a multiphase data sampling unit for converting each received burst data sets to multiphase data trains, a phase determination unit for generating a control signal indicating an optimum phase data train, an output data selector for selectively passing optimum phase data train indicated by the control signal, and a data synchronization unit for converting the optimum phase data train to a data train in synchronization with a reference clock. The phase determination unit repeatedly detecting the optimum phase data train during the same burst data set is received. When optimum phase varies, the output data selector dynamically switches the optimum phase data train to be supplied to the data synchronization unit.

Abstract: The present invention relates to a wavelength multiplexing apparatus for multiplexing and/or demultiplexing a plurality of optical signals in the wavelength region and a signal conversion apparatus for interfacing a transmission line corresponding to any of the optical signals with the wavelength multiplexing apparatus. By using these apparatus according to the invention, the signal to be a reference for synchronization between the wavelength multiplexing apparatus and the signal conversion apparatus is reliably delivered via an existing optical transmission line therebetween, without the reduction of transmission quality and the limitation on modulation systems. Therefore, in an optical transmission system with the present invention applied thereto, it is possible to meet conditions for office establishment and arrangement of the apparatus and satisfy the demands for maintenance/operation flexibly and at a low cost. Further, service quality and reliability are maintained at high levels.

Abstract: Disclosed herein is a method of optically producing a clock, in which clock components are extracted from the spectrum of a transmitted optical signal and the influence of noise and jitter on the extracted clock components is reduced, thus improving the stability of an optical communication system. In the clock producing method of the present invention, a plurality of clock components are extracted by filtering out frequency bands between neighboring intensity peaks, and then a clock having reduced noise and jitter is produced by logically ANDing two or more of the plurality of clock components extracted at the step of extracting the plurality of clock components.

Abstract: The invention provides a transceiver circuit for communication that enhances the operation frequency of a synchronous digital circuit up to the maximum frequency of a flip-flop and inhibits the occurrence of jitters. A clock signal synchronized with data at f1/n Hz is converted by a multiplier so that the signal has a frequency of “n” times so as to use the clock signal for triggering a flip-flop the operation frequency of which is f1 b/s in the synchronous digital circuit. The multiplier is arranged in the vicinity of the flip-flop triggered by the clock signal of f1 Hz so as to avoid the effect of the deterioration of the operation frequency by interconnect capacitance. The maximum operation frequency of the transceiver circuit determined based upon the operating frequency of the synchronous digital circuit can be enhanced up to the maximum operation frequency of the flip-flop.

Abstract: A method and system for synchronizing a local optical clock with a master optical clock, wherein the local clock generates a local clock signal at a local clock wavelength, and said master clock generates a master clock signal at a master clock wavelength. The method comprises the steps of dithering the wavelengths of the local and master clock signals, and generating a control signal representing the difference between the dithered wavelengths of the local and master clock signals. That control signal is then used to synchronize the local clock with the master clock. Preferably, a wavelength-locked loop is used as a means of phase or wavelength control for the optically distributed clock signals. The wavelength-locked loop provides a technique to control the wavelength of a local optical clock source in a manner that will allow the local clock to follow variations in the wavelength of another optical signal.

Abstract: The invention is also related to devices for a synchronization of data in an optical WDM transmission system, consisting of the following parts: A wavelength demultiplexer (1) for demultiplexing the incoming data stream in the synchronizer, delay lines (2) for the individual wavelength channels, a multiplexer (10), a modulator (3) modulated by a high frequency clock signal (5) and at least one photodetector (4) tapped to output line (B) where the photodetector (4) is connected to an electronic control circuit (6) which is connected to the findividual delay lines (2) for an automatic delay control.

Abstract: This invention provides a technique for realizing low-cost optical signal waveform monitoring with improved realtimeness to be applied to signal quality monitoring in an actual optical transmission system, and a technique for stably controlling an optical transmitter/receiver and various compensators by means of this waveform monitoring. Opening/closing of a optical gate is controlled by means of a clock signal synchronized with an optical signal input from a photocoupler and having a period equal to the bit interval of data or N (N: a positive integer) times longer than the bit interval to allow each pulse of the optical signal for one bit of data to pass through the optical gate for only part of the time width of the gate. A photoelectric conversion element to which the optical signal transmitted through the optical gate for only part of the time width obtains an average light intensity of the input optical signal. Information on this average light intensity is output to a monitoring output section.

Abstract: The present invention provides a robust solution to the task of re-aligning data at the transmit end of a fiber optic or other high performance serial link, and also offers flexibility in the circuit board design approach. A high performance analog phase locked-loop circuit is used to simultaneously provide clock recovery for multiple bit streams. The power dissipation required to perform clock recovery is thereby reduced to a fraction of that required in conventional transmit systems. This analog phase locked loop produces plural phase output signals. An output multiplexer selects one phase for use in electrical to optical conversion.

Abstract: A method and system for reducing non-linear signal degradation effects of WDM optical signals exacerbated by highly correlated bit patterns of optical waveforms in neighboring optical channels. Embodiments include offsetting the transmission times of signals in neighboring channels, and applying different scrambling patterns to the respective data streams prior to transmission on neighboring optical channels.

Abstract: An optical stream is split into a primary optical stream and a secondary optical stream. The secondary optical stream is converted to an electrical signal. The electrical signal is processed to identify a particular portion of the optical stream. The primary optical stream is delayed to provide a delayed optical stream. The particular portion of the delayed optical stream is modified to provide a controlled impairment.

Abstract: Cost-reduction in an optical communication unit is achieved by using spectrum-sliced modulated broadband light for transmitting upstream signals, instead of using laser light. An optical communication system includes at least one pair of optical communication units that each has a bi-directional network interface in which physical bit rates of transmission signals and reception signals are identical, an optical transmitter, and an optical receiver, and that performs bi-directional transmissions via at least one optical fiber. One optical communication unit includes a physical bit rate down-converter that lowers the physical bit rate of transmission signals from the bi-directional network interface and outputs to the optical transmitter, and the other optical communication unit includes a physical bit rate up-converter that raises the physical bit rate of signals received by the optical receiver and outputs to the bi-directional network interface.

Abstract: This invention discloses a method to easily extract a header from an optical packet. An optical data transmission method to transmit an optical packet composed of a header and data containing steps of generating a second clock which has a frequency equal to one integer of that of a first clock carrying the data and synchronizes with the first clock, and carrying the header information on the second clock.

Abstract: An optical receiver is provided with inputs for receiving two fiber optic lines. The two fiber optic lines carry redundant data. An optical interface passes the respective signals therein to a comparison unit. The comparison unit compares the signals and determines which has the better quality and passes the better quality signal on to a processing interface. Clock data for operating the comparison unit is extracted from the optical signals.

Abstract: In an optical multiplexing interconnection module, first and second NRZ input signals synchronous by clock signal are inputted to its input section. The first NRZ input signal is converted to a first RZ signal according to a logical product with a clock signal CLK by a drive circuit and the second NRZ input signal is converted to a second RZ signal according to a logical product with an inversion clock signal by a drive circuit. Then, light emitting devices are driven according to the first and second RZ signals from these drive circuits and two optical signals from the light emitting devices are inputted to an optical channel and multiplexed therein and then, a multiplexed optical signal is transmitted through an optical channel.

Abstract: A wavelength-division multiplexed optical transmission system to keep the correlation of data patterns among wavelength channels to the low level, preventing large XPM and XGM from occurring when the correlation is strong, and assuring a stable transmitting quality.

Abstract: A technique for determining an arbitrary delay in a source code word propagated over a channel that introduces the arbitrary delay in the source code word to produce a received code word. The technique is based upon a multiple-shift algorithm to determine the delay by a coarse synchronization process to locate synchronization as contained within a composite code pattern, and a fine synchronization process to pinpoint the delay by examining shifts in the source code word used to form the composite code pattern.

Abstract: A device and method for correcting for timing jitter of an optical data pulse in an optical transmission system. During transmission, a data pulse may suffer jitter. Its arrival time at a node may be temporally offset from its predicted arrival time. Data pulses are timed so that they may be received at a detector disposed downstream of the node at a predetermined time. The device includes a source of chirped optical pulses and a node, which has a first input arranged to receive a chirped optical pulse. The node has a second input arranged to receive a data pulse. The node includes an optical gate arranged to generate an output pulse in response to the first pulse and the data pulse received at the first and second inputs, respectively, having a wavelength dependent upon the time at which the data pulse is received at the second input. The device further includes an optically dispersive medium after passage through which, the output pulses are correctly retimed in order to correct for the timing jitter.

Abstract: All optical clock recovery includes a transmitter for generating an optical timing signal. The transmitter includes a semiconductor laser for the production of a dynamically synchronizable timing signal, the laser having an external resonator for feedback of the timing signal to the laser, the feedback having a delay time greater than a relaxation oscillation time for the laser, and the laser outputting an optical timing signal having a characteristic dynamic. The transmitter supplies the optical timing signal to a receiver configured to receive the timing signal and to synchronize to the laser on receipt of the timing signal, such that the receiver outputs a recovered timing signal having the characteristic dynamic.

Abstract: A method and system for self-synchronizing an optical packet network by selecting a seed pulse from among the data pulses within a packet having no synchronization marker, transforming the seed pulse to be optically distinguishable from the remaining data pulses after the packet has been transmitted, and extracting that seed pulse for use in synchronizing the operation of the network. In one embodiment, the process is practiced using a intensity modifier (such as a fast-saturation, slow-recovery amplifier) to modify the seed pulse intensity, and an intensity discriminator (such as an unbalanced NOLM, or a dispersion-shifted fiber and bandpass filter) to extract the differentiated seed pulse.

Abstract: A method and apparatus for optical performance monitoring that provides for multi-rate and multi-protocol monitoring includes, identifying a protocol associated with each of a plurality of communication signals using respective data rates extracted therefrom, determining, for each of the plurality of communication signals, a respective bit-error rate (BER), and generating an alarm indicative of BER excursions beyond a protocol appropriate BER threshold level.

Abstract: A system that transmits amplitude modulated data in a wavelength-encoded format and then uses a wavelength-sensitive receiver to convert the received optical signal back to the original amplitude modulated data. This system enables transmission of optical signals that are less sensitive to attenuation and attenuation changes. This system is applicable to data in digital, multilevel, or analog formats.

Abstract: A transmitter comprises an oscillator, a phase lock loop, a serializer, and an electrical-to-optical converter. The oscillator is enclosed in a metal shield. The metal shield is soldered to a ground ring of the printed circuit board. In one embodiment, the oscillator is voltage-controlled oscillator.

Abstract: An apparatus and method generating an optical pulse of picosecond class (having a high duty ratio), which accurately and stably operates at an arbitrary repetition frequency, has a high OSNR, and is not restricted by an RF modulation frequency, are provided. New modulation spectrum components are generated by performing phase modulation for light output from a single wavelength laser light source with an optical phase modulator. The phases of the modulation spectrum components are aligned by a phase adjuster, so that a pulse wave in a time domain is generated.

Abstract: An arbitrary number of signaling beacons are synchronized simultaneously and automatically by a received modulated control signal in accordance with an arbitrary communication protocol over a communication link which may be separate from or superimposed upon a perceptible signal periodically provided from signaling beacons. The periodic perceptible signal may be stabilized using a crystal oscillator or an external transmitted signal such as a global positioning system (GPS) signal and synchronization thus maintained for extended periods of time even when the synchronization communication link is not available. Interference is substantially prevented by the communication protocol while supporting the provision of any desired beacon control functions.

Abstract: A device and technique for aligning an optical carrier signal (e.g., a soliton pulse train) with a data signal in a transmitter. According to the invention, the device is configured to analyze the radio frequency (RF) spectrum of the transmitter's output. In one implementation, the device evaluates the amount of energy in a certain frequency band located near a selected null of the RF spectrum. In another implementation, the device examines the shape of the RF spectrum within that frequency band. In either case, based on the analysis, the device adjusts the phase of the clock signal driving an electro-optic (E/O) modulator in the transmitter. Such adjustment reduces misalignment between the optical carrier signal and data resulting, e.g., from thermal effects in the E/O modulator. The device may be used, e.g., in long-haul optical transmission systems operating at 10 GBit/s.

Abstract: A clock recovery circuit for synchronizing a clock signal having frequency of approximately f0 with an optical data signal having a frequency of N×f0, where N is an arbitrary rational number, includes a local oscillator for generating the clock signal, a sampler for producing an output signal indicative of a phase difference between the clock signal and the optical data signal, an optical detector coupled to detect the output signal as an electrical signal, and a mixer for isolating at least one harmonic of the electrical signal and for downconverting the at least one harmonic to a baseband error signal. The local oscillator is tuned in response to the baseband error signal to synchronize the clock signal with the optical data signal.

Abstract: A detecting circuit detects a boundary in a bit stream which is coded in compliance with a predetermined rule. The boundary is a point at which discontinuity of reproduction time occurs. An inverting circuit inverts a specific bit in a header of a succeeding bit stream immediately subsequent to the boundary, in response to the detection of the boundary by the detecting circuit. The boundary can thus be detected easily by simply monitoring the specific bit, for example, in outputting the decoded bit streams. This consequently facilitates synchronous management and the like of the bit streams. The specific bit is included in the bit stream. Thus, detecting the specific bit allows simple and accurate detection of the boundary at which discontinuity of the reproduction time occurs.

Abstract: An optical transmitter for transmitting a first output data signal and a second output data signal, the optical transmitter comprising: a phase-locked-loop, the phase-locked-loop operable to receive a reference clock signal; a clock-recovery circuit, the clock-recovery circuit coupled to the phase-locked-loop, the clock-recovery circuit operable to receive a first input data signal; a latch-decision circuit, the latch-decision circuit coupled to the clock-recovery circuit; a latch, the latch coupled to the latch-decision circuit, the latch operable to receive the first input data signal and the second input data signal; a first electro-optical converter, the first electro-optical converter coupled to the latch, the first electro-optical converter operable to transmit the first output data signal; and a second electro-optical converter, the second electro-optical converter coupled to the latch, the second electro-optical converter operable to transmit the second output data signal.

Abstract: The invention has for its object to provide a monitoring unit, particularly for optical burst mode signals in asynchronous optical networks based on, e.g., Internet or ATM (ATM=asynchronous transfer mode). The monitoring unit for burst mode signals comprises a detector for performing a Q-factor measurement in dependence on at least one variable and at least one fixed amplitude threshold value and on at lest one variable and at least one fixed phase value. This detector contains a burst mode amplitude detector for generating a fixed amplitude threshold value for each burst, a burst mode clock recovery circuit for generating a fixed phase value for each burst, a burst detector for detecting the beginning of each burst, and a control logic for generating a variable amplitude threshold value and a variable phase value for each burst.

Abstract: A system and method of selecting and viewing communication traffic transmitted over an optical channel selected from among a plurality of possible channels without disrupting the communication traffic occurring over the selected channel or other channels is presented. The system and method includes an optical channel analyzing switch which taps each of the possible plurality of channels and selects a specific channel for routing to a network analyzer. The signal on the selected channel, prior to being analyzed by the network analyzer, undergoes clock and data recovery and retiming/recombination to mitigate contamination from routing and switching the selected original signal between the signal source and the network analyzer. The retimed and recombined channel signal results in a signal, as presented to the network analyzer, which is representative of the original channel signal.

Abstract: According to a PLL circuit of the present invention, an output of a phase comparator is adjusted according to a space-to-mark transition-probability of an input signal so that an output of a voltage controlled oscillator has a predetermined frequency and phase. Therefore, even when a phase of a timing clock is set other than at 0, an output of the PLL circuit can be kept at the set phase, irrespective of the space-to-mark transition-probability. By using the PLL circuit as such in an optical communication apparatus and an optical communication system, a discrimination point can be kept almost fixed, and therefore, it is possible to lower an error rate.

Abstract: Proposed is an optical clock distribution system in the WDM network, which particularly relates to a system to control clock synchronization between optical transmission devices constituting an optical communication network. The optical clock distribution system includes an optical clock generator converting a clock signal of PRC (Primary Reference Clock) level into an optical clock signal having a wavelength ?0; a wavelength multiplexer wavelength-multiplexing the optical clock signal having wavelength ?0 together with other optical wavelength data; and a wavelength-demultiplexer provided in a unit of the network, wavelength-demultiplexing the optical clock signal having wavelength ?0, wherein the other optical wavelength data are processed in the unit of the network using the wavelength-demultiplexed optical clock signal having wavelength ?0 as a reference clock.

Abstract: An optical retimer is provided that retimes an optical data signal entirely in the optical domain, thus eliminating the need for optical-to-electrical and electrical-to-optical converters, which are needed to perform retiming in the electrical domain. Eliminating these conversion steps also eliminates, or at least decreases, the potential for errors in the retimed optical signal, such as jitter. The optical retimer samples the optical data signal during a clock cycle that has been determined by clock recovery, allows the sampled signal to traverse an optical pathway for the remainder of the cycle, out-couples a fraction of the sampled optical signal each time the signal traverses the optical pathway, and amplifies the signal traversing the pathway to maintain the signal at the power level it had when it was sampled. By the end of the clock cycle, the out-coupled signal corresponds to a retimed version of the original signal, synchronized to the recovered clock signal.

Abstract: A wavelength converter and a wavelength division-multiplexing optical communication apparatus automatically generate clock signals of a specified frequency that match send/receive digital signals and regenerates timing for the send/receive digital signals. The wavelength converter includes: optical/electrical signal converters (2A, 2B) that convert input optical signals into electric digital signals; clock generator circuits (4A, 4B) that automatically identify the transmission mode for digital signals and generate phase-synchronized clocks of a specified frequency that match the signal transmission mode; timing regeneration circuits (6A, 6B) that regenerate clock timing for the digital signals based upon the phase-synchronized clocks from the clock generator circuits; and electric/optical converters (3A, 3B) that convert the digital signals from the timing regeneration circuits into optical signals of a specified wavelength.

Abstract: An optical line interface assembly for insertion in a slot of a communications equipment rack includes a board having serial interfaces formed to couple to optical interface modules. The interface assembly also includes optical interface modules removably coupled to the serial interfaces to permit replacement of selected optical interface modules while the remaining optical interface modules remain coupled to optical signal lines.

Abstract: An all-optical 3R regenerator (AO3R) and a method for using the AO3R to retime, reshape and retransmit an optical signal are described herein. The AO3R includes a polarizer that receives an input optical signal which is of unknown, potentially varying phase and outputs a stable polarized input optical signal. The AO3R also includes a first interferometer (e.g., interferometric converter module) that retimes and reshapes the polarized input optical signal and transmits the retimed and reshaped polarized input optical signal as a polarized output optical signal. The first interferometer is able to retime the polarized input optical signal with the aid of a laser and a clock recovery mechanism.