Abstract: A bit rate control apparatus having a delay unit for delaying an input signal received in an optical receiver in an optoelectrically-converted state; a DC level outputting unit for exclusively OR'ing the input signal with the delayed signal outputted from the delay unit; an A/D converting unit for A/D converting a DC level outputted from the DC level outputting unit; a clock/data reproducing unit for reproducing clocks and data based on a bit rate control signal; and a control unit for calculating a variation in the DC level at every interruption timing, which is previously set, based on the A/D converted signal, and for determining whether the DC level variation occurs under the influence of temperature or due to a variation in bit rate based on a difference between the calculated DC level variation from a predetermined variation limit.

Abstract: A method and apparatus for providing optical 3R regeneration involving: 1) generating an encoded optical clock signal from at least an optical signal; 2) introducing the encoded clock signal into a delay interference section of a regenerator such that an amplitude modulated clock signal is produced; andoutputting the amplitude modulated clock signal wherein the output amplitude modulated clock signal preserves information present within the input optical signal.

Abstract: Disclosed is a bit-rate-independent optical receiver including: a bit rate sensing unit for optoelectrically converting an input optical signal, while outputting a bit rate sensing signal; a variation sensing unit for outputting a bit rate variation sensing signal; a temperature sensing unit for sensing an internal temperature and outputting a temperature sensing signal; a signal reproducing unit for reproducing data and clocks, and in response to a clock correction signal, reproducing the data and clocks based on the clock correction signal; and, a control unit for calculating the bit rate based on the voltage level of the bit rate sensing signal in response to receiving the variation sensing signal, and compensating the calculated bit rate for errors resulting from a variation in temperature, and outputting a clock correction signal indicative of the temperature-compensated bit rate to the signal reproducing unit.

Abstract: The invention relates to wavelength division multiplex fiber optic transmission systems. It proposes a regenerator including a demultiplexer for separating the signals of various channels, a plurality of optical modulators each receiving signals from the demultiplexer and a modulation clock from a clock distribution unit, and a multiplexer combining the signals modulated by the modulators. The clock distribution unit includes a reference clock and, for each modulator, means for synchronizing the phase of a copy of the reference clock with the signals applied to the modulator. A phase-locked loop can be used for phase synchronization, with a phase shifter controlled in accordance with the average power of the signals at the output of the modulator. The invention enables only low-frequency components to be used to generate modulation clocks from a single reference clock.

Abstract: Disclosed herein is a method and device for waveform shaping of signal light. The method includes the steps of providing a waveform shaper for waveform shaping input signal light and outputting output signal light, measuring the quality of the output signal light, and controlling the power of the input signal light so that the quality measured is improved. According to this method, a substantially optimum threshold can be obtained to allow a good regenerating operation.

Abstract: In a method and system for evaluating distributed gain in an optical transmission system, a data signal and a residual pump laser signal propagating in opposite directions within a waveguide are monitored. Modulation of the residual pump laser signal is correlated with low frequency components of the data signal. This correlation is used to determine cross-talk between the data signal pump laser signals, as a function of location within the waveguide. The distributed gain is then evaluated from the cross-talk, using a known relationship, or proportionality, between gain and cross-talk.

Abstract: A delayed interference all-optical wavelength converter is arranged to convert and reshape a pulsed input signal Pin at &lgr;1 into the wavelength converted signal Pconv at &lgr;2, where &lgr;1 and &lgr;2 are different. A delayed interference all-optical wavelength regenerator is similar, but is arranged to reshape a pulsed input signal Pin into the wavelength converted signal Pconv, where the wavelengths of the input signal and the converted signal are the same. The converter/regenerator comprises an input-signal coupling unit for receiving the pulsed input signal and supplying it to one input of a modulation section, the other input to which is a carrier signal Pcw. The output of the modulation section Pint, which is generally speaking, a phase modulated signal which may also have an amplitude modulated component, is applied to a delay interference section arranged to transform Pint into a primarily amplitude-modulated signal.

Abstract: An optical transponder capable of effecting performance monitoring on the electrical signal equivalents of at least two different optical signal types each uniquely identifiable in terms of transmission protocol and/or bit rate. The optical transponder includes an optical/electrical (O/E) receiver module for converting an ingressing optical signal from an optical signal source into an electrical signal; a performance monitoring module for effecting performance monitoring on the electrical signal; and an electrical/optical (E/O) transmitter module for regenerating an egressing optical signal from the electrical signal for feeding to an optical signal destination.

Abstract: An optical transmission system is provided which uses optical single-sideband (SSB) modulation and incorporates at least one mid-span analog SSB regenerator arranged to produce a phase conjugation of the transmitted signal. The phase conjugation technique, referred to here as complementary sideband regeneration (CSR), is accomplished on the retransmitted optical signal in the electrical domain, and requires no nonlinear optical techniques.

Abstract: An optical repeater which includes a wavelength converter and a bit rate converter. The wavelength converter converts a wavelength of an optical signal from a first optical network to a wavelength of a second optical network. The bit rate converter converts a bit rate of the optical signal from the first optical network to a bit rate of the second optical network. The optical repeater transmits the optical signal from the first optical network to the second optical network at the converted bit rate and wavelength.

Abstract: A regenerator for an RZ optical signal transmission system applies a relative time shift to the signals as a function of their intensity and includes an intensity modulator for modulating the shifted signals. The shift between signals corresponding to a “zero” value and signals corresponding to a “one” value is such that the modulation intensity for signals corresponding to a “zero” value is less than the modulation intensity for signals corresponding to a “one” value. A shift equal to half the bit time between signals corresponding to a “one” value and signals corresponding to a “zero” value can therefore be chosen. The modulation intensity is then maximum for signals corresponding to a “one” value and minimum for signals corresponding to a “zero” value. The regenerator limits noise in the “zeros” of an RZ signal and regenerates the “ones”.

Abstract: A gain equalizer which equalizes gain versus wavelength characteristics of an optical amplifier. The gain versus wavelength characteristics of the optical amplifier include first, second and third gain peaks in a wavelength band with the second gain peak being between the first and third gain peaks. The optical amplifier amplifies an input signal in accordance with the gain versus wavelength characteristics to produce an output signal. The gain equalizer includes first, second and third optical filters having first, second and third transparency characteristics, respectively. The first, second and third transparency characteristics are periodic waveforms having different periods related to the wavelength difference between the first and third gain peaks. The second transparency characteristic is a periodic waveform having a period equal to 1/(2n) of the period of the waveform of the first transparency characteristic.

Abstract: The invention relates to a device for regenerating optical signals by intensity modulation and phase modulation of the optical signals, said device including: a mode locking laser for recovering a clock signal representing the clock of the bits of the optical signals to be regenerated, and a modulation interferometer structure having a first interferometer arm and a second interferometer arm, enabling amplitude modulation and phase modulation of optical signals by said clock signal, and including a semiconductor amplifier in the first interferometer arm. The mode locking laser is coupled to said first interferometer arm so that said amplifier of the first interferometer arm is a common component of the mode locking laser and said interferometer structure.

Abstract: A WDM optical transmission system in which a retiming unit disposed at the front stage of the optical signal supplying unit of an optical transceiver is provided. The pulse width distortion of an optical signal generated in optical transmission through an optical fiber between two WDM optical transmission apparatus is corrected by the retiming unit after the optical signal has been demultiplexed and converted into an electrical signal.

Abstract: An optical signal regenerative repeater is provided including at least one first optical 3R repeater based on an optical communication signal pulse, regenerating the optical communication signal pulse. The first optical 3R repeater comprises a first clock extraction unit extracting a clock from the optical communication signal pulse and generating a first optical clock pulse synchronized with the extracted clock. The first optical 3R repeater also comprises a first optical gate, which is opened and closed in accordance with a control light corresponding to the optical communication signal pulse, which receives as a controlled light the first optical clock pulse generated by the first clock extraction unit, and which generates a first regenerated signal pulse corresponding to said optical communication signal pulse. Further, a pulse time width of the control light and the controlled light is different.

Abstract: Disclosed herein is an optical signal processing device which can give stable temporal order to the modulation-phases of a plurality of optical signals. The optical signal processing device includes an optical demultiplexer and an optical multiplexer for adaptation to WDM (wavelength division multiplexing). The optical demultiplexer has an input port and a plurality of output ports. The input port is adapted to accept WDM signal light obtained by wavelength division multiplexing a plurality of optical signals having different wavelengths. The optical multiplexer has an output port and a plurality of input ports. The plural output ports of the optical demultiplexer and the plural input ports of the optical multiplexer are connected by a plurality of optical paths, respectively. Each optical path is provided with a delay adjuster.

Abstract: An optical signal regeneration device having an interferometric structure with two arms. Each of the arms has a medium, the optical power output of which is variable with the optical power input. The first arm receives, through an input coupler, a continuous wave and the signal to be regenerated. The second arm receives through the input coupler, a continuous wave signal and a clock signal. A filter, centered on the continuous wave wavelength, receives the output signal of the interferometric structure through the coupler. The filter output signal constitutes the regenerated 3R signal.

Abstract: An optical 2R/3R regenerator is described. One or more LSOAs are used as part of the optical 2R/3R register.

Abstract: [The aim of the invention is to realize both 3R regeneration as well as an adjustable wavelength conversion with one component. The 3R regenerator should be constructed with components that are less technically complex than those of the prior art. In a] A 3R regenerator which is provided with wavelength conversion and which comprises means for generating clock pulses, a non-linear discriminator, and means for generating and/or adjusting the output wavelength, [the invention provides that] the means for generating and/or adjusting the output wavelength [is] being a laser. [This laser, in addition to the means for generating clock pulses to the discriminator, is constantly operated, is connected to the discriminator, and its light having the desired wavelength is beamed into the discriminator. A delay line is located between the means for generating clock pulses and the discriminator.

Abstract: A balun is constructed from a parallel pair of lines (coaxial or bifiler) that are bent to form a U-shape including a more curved (bent) section with two ends each of which are connected to a respective less curved (straight leg) section. One or more single hole ferrite beads are threaded over each respective pair of less curved sections of the pair of lines.

Abstract: A network control system may be embodied in various elements of a communication network which communicates optical signals multiplexed by wavelength division multiplexing (WDM). In a preferred embodiment of the invention, the network control system limits a number of channel wavelengths actually used for communicating the optical signals to an end node to a highest number N of separable channel wavelengths at the end node. In another preferred embodiment of the invention, the network control system controls and modifies, as necessary, data rates carried over channel wavelengths multiplexed by WDM in order to reduce interference and improve performance of the communication network.

Abstract: A data regenerator for regenerating a data signal, including a convertor for converting a received data signal into a binary data signal in dependence on conversion parameters, an error corrector for correcting errors in the binary data signal based on error correction code contained in the binary data signal to produce a corrected binary data signal, and a performance monitor for comparing the corrected binary data signal with an uncorrected representation of the binary data signal to determine information about the relative number of logic“1”s and logic “0”s that have been corrected by the error corrector and output a feedback signal representative of the relative number, wherein the convertor adjusts at least some of the conversion parameters in dependance on the feedback signal.

Abstract: A compensation arrangement compensates for data signal changes from one of a group consisting of timing jitter dispersion and adaptive chromatic dispersion in an optical signal using a temporal imaging technique. An optical data input signal to the compensation arrangement includes a data pulse for each bit of data that have been subjected to a data signal change. In the compensation arrangement, a clock recovery arrangement generates an electrical clock output control signal including a predetermined phase modulation depth and phase and a data rate of the received optical input data signal. A phase modulator is responsive to the optical input data signal and the electrical clock output control signal from the clock recovery arrangement for generating an optical output signal. In this optical output signal, the phase of the data signal change associated with each data bit is delayed by a predetermined amount.

Abstract: A method of modulating an optical signal is provided comprising the steps of providing a first electric field in a first optical signal path, providing a second electric field in a second optical signal path, transmitting an optical signal along the first optical signal path and the second optical signal path, amplitude modulating the optical signal via the first electric field and the second electric field, and phase modulating the optical signal via the first electric field and the second electric field. A clock source and a data source are ANDed to provide a data modulated RF signal on an offset waveguide electrode for generating the first and second electric fields. The magnitude of the electric field of the first electric field in the first optical signal path is greater than the magnitude of the electric field of the second electric field in the second optical signal path.

Abstract: A method and apparatus for all-optical signal regeneration in fiber optic communications networks is provided. The process utilizes solitary wave interactions in various nonlinear optical media to re-shape, re-amplify and re-time optical signals that have traveled over large distances of fiber-optic cable. The device consists of an optical clock generator synchronized to the system clock, recovered from the input signal by a clock recovery unit. The output of the optical clock is then used to produce a solitary wave in the nonlinear material that collides with the coincident signal beam. The net result is an all-optical signal regenerator. A multi-channel device capable of providing signal regeneration on multiple wavelengths using a single clock recovery and optical clock generator assembly is also disclosed.

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.

Abstract: The invention concerns a fiber optic soliton signal transmission system comprising a signal amplifier means and signal regenerator means, in-line first filter means and second filter means associated with the regenerator means, the second filter means being different from the first filter means. Independent optimization of the in-line filter means and the filter means associated with the regenerator improves the performance of the transmission system. In the case of wavelength division multiplexed systems, the invention reduces the effects of jitter induced by collisions between solitons.

Abstract: In a first J/B 11 and a second J/B 12 in a vehicle, first photoelectric conversion sections 21 to 23 are disposed corresponding to respective electric apparatuses, a fourth photoelectric conversion section 24 is disposed to be connected to an optical transmission line, and first switch circuits 31 to 34 are disposed corresponding to the first photoelectric conversion sections 21 to 24, respectively. In these first J/B 11 and second 12, for example, if a break occurs in the optical transmission line which connects the first photoelectric conversion section 21 to the electric apparatus, a system is rebuilt, in which the first switch circuit 31 is closed to relay an electric signal by bypassing the first photoelectric conversion section 21.

Abstract: An optical repeater includes an optical splitter for splitting an optical input data pulse stream of wavelength &lgr;0 into first and second components. The first component is supplied to a first. mode-locked laser diode to produce a first clock pulse stream of wavelength &lgr;1 which is synchronized to the input data pulse stream. The first clock pulse stream is fed to a second mode-locked laser diode to produce a second clock pulse stream of wavelength &lgr;0 which is synchronized to the first clock pulse stream. The second clock pulse stream is entered to an optical gate. The second component of the input data from the splitter is amplified sufficiently to control the optical gate to modulate the second clock pulse stream so that the data pulse pattern is impressed on the second clock pulse stream.

Abstract: The invention relates to a method of reducing the intensity distortion induced by cross phase modulation in a wavelength division multiplexed optical fiber transmission system comprising a transmission line made up of a plurality of optical fiber segments with repeaters interposed between successive optical fiber segments, the transmission system having N different wavelength channels, where N is an integer greater than unity. In each repeater interconnecting first and second consecutive fiber segments, a time offset is introduced between the channels in such a manner that compared with the inlet of the first optical segment, the (n+1)th and the nth channels are offset by &tgr;n at the inlet to the second fiber segment, where n is an integer less than or equal to N, where &tgr;n is selected to be greater than zero and less than a value that eliminates correlation between the intensity distortion contributions of each fiber segment.

Abstract: An optical translator that includes an interferometer and a plurality of semiconductor optical amplifiers (SOAs) coupled to the interferometer. The at least two of the SOAs receives data and a clock signal. The data is received by the at least two SOAs at different times. A coupler combines each of a respective output of the at least two SOAs to provide output data. The output data is a retimed and a reshaped signal of the data provided to at least one of the plurality of SOAs.

Abstract: A method of providing power via a power cable to optical line units for amplification of an optical signal propagating along an optical fiber having a first end and a second end and terminated solely at the first end and the second end is provided comprising terminating the power cable at a location between a first plurality of line units and a second plurality of line units.