Abstract: An optical repeater device of the present invention comprises: a preamble compensating circuit 53, for taking out a normal data signal from burst signals propagating through a communication transmission path, and for adding a preamble signal before and/or after the data signal. Furthermore, the preamble compensating circuit 53 comprises: a detector circuit 53a, for inputting the burst signal, and for outputting only the normal data signal; a buffer circuit 53b, for storing the data signal output from the detector circuit 53a, and for outputting thereof; a preamble signal generation circuit 53d, for outputting at least one type of the preamble signal; and an data output select circuit 53e, for outputting the data signal at the time of the data signal input from the buffer circuit 53b, and for outputting the preamble signal from the preamble signal generation circuit 53d at any other time thereof.

Abstract: An all-optical modulation format converter for converting optical data signals modulated in an on-off-keying (OOK) format to a phase-shift-keying (PSK) format. The OOK-to-PSK converter can be coupled to a delay-line interferometer to provide an all-optical wavelength converter for differential PSK (DPSK). The OOK-to-PSK converter can also be used in all-optical implementations of various functions, including, for example, exclusive-OR (XOR/NXOR) and OR logic, shift registers, and pseudo-random binary sequence (PRBS) generators.

Abstract: Systems and methods for unidirectional communication in an optical network employing bidirectional transponders are provided. The modulation and amplification capabilities of the bidirectional transponder are used to forward information to the next node. In this way a highly cost-effective “drop and continue” architecture is provided. In one implementation, the client-side output of the bidirectional transponder is looped back to the client-side input using, e.g., a Y-cable fiber. In this way, a unidirectional signal present on a network-side input wavelength to the transponder is presented both on a network-side output wavelength of the transponder and at the same time to a client. The modulation and amplification capabilities of the bidirectional transponder are thus exploited in forwarding the unidirectional signal to the next node.

Abstract: During initial start-up of an optical communication system, an ASE reference span loss is calculated based on transmitting power and received power of ASE light generated by an optical amplifier, and an OSC reference span loss is calculated based on the transmitting power and the received power of OSC light. During normal operation of the optical communication system, a span loss is calculated using the OSC light, and an amount of change in the span loss representing a difference between the span loss and the OSC reference span loss is calculated. A current span loss between a transmitting station and a receiving station is calculated by adding the amount of change in the span loss to the ASE reference span loss.

Abstract: Systems and methods for operating transponders that automatically accommodate multiple received signal types. The different signal types may include different clients such as, e.g., SONET/SDH, G.709, 10 Gigabit Ethernet, etc. as well as different data rates. A transponder can automatically detect the client signal type and data rate and respond by processing the received signal appropriately, notifying a control processor, and invoking an appropriate performance monitoring method. This maximizes the network operator's flexibility and ease of configuration.

Abstract: System and method for dispersion compensation tuning for a WDM optical transmission system. A tunable dispersion compensation module (4) is located at or substantially close to a transmitting end of the optical transmission line (2) and at least one distributed Raman amplifier having an Raman pump (1) is coupled to the transmission line 2. The dispersion compensation is controlled by means of a signal derived from the Raman pump (1) which is fed through a control loop (3) to the tunable dispersion compensation module (4).

Abstract: Methods and apparatus for providing amplification to coarse wave division multiplexing channels or signals are disclosed. According to one aspect of the present invention, an arrangement that adds gain to a set of signals that may be divided into a first band including signals of lower wavelengths and a second band including signals of higher wavelengths includes a multiplexer, first and second optical amplifiers, and a processing arrangement. The multiplexer multiplexes the set of signals. The first optical amplifier has a first gain peak and provides amplification to the set of signals, while the second optical amplifier has a second gain peak and provides amplification to the second band but not to the first band. The processing arrangement passes the second band from the first optical amplifier to the second optical amplifier, and substantially prevents the first band from passing from the first optical amplifier to the second optical amplifier.

Abstract: Signal light, pumping light and control light having different wavelengths are input to a nonlinear optical medium. The power of the pumping light is controlled to generate a desired gain in the nonlinear optical medium. The power of the control light is controlled to saturate the gain of the nonlinear optical medium.

Abstract: A device for processing of an optical input signal includes at least a first data signal. A first optical resonator provides a reference signal by optical filtering of the optical input signal. The first optical resonator is matched with a predetermined reference wavelength of the first data signal. A second optical resonator provides a sideband signal by optical filtering of the optical input signal. The second optical resonator is non-matched with the predetermined reference wavelength of the first data signal. An optical combiner combines the sideband signal with the reference signal to form an optical output signal.

Abstract: An optical device for regenerating an optical clock, including an optical path provided between an input port to which signal light modulated at a frequency fs is supplied and an output port, and an optical loop optically coupled to the optical path. The optical loop includes an optical amplifier for compensating for a loss in the optical loop so that laser oscillation occurs in the optical loop, an adjuster for adjusting the optical path length of the optical loop so that the frequency fs becomes equal to an integral multiple of the reciprocal of a recirculation period of the optical loop, and a nonlinear optical medium for mode-locking the laser oscillation according to the signal light.

Abstract: An all-optical modulation format converter for converting optical data signals modulated in an on-off-keying (OOK) format to a phase-shift-keying (PSK) format. The OOK-to-PSK converter can be coupled to a delay-line interferometer to provide an all-optical wavelength converter for differential PSK (DPSK). The OOK-to-PSK converter can also be used in all-optical implementations of various functions, including, for example, exclusive-OR (XOR) logic, shift registers, and pseudo-random binary sequence (PRBS) generators.

Abstract: An all-optical processor and method for simultaneous 2R regeneration of the multiple wavelength-division-multiplexed (WDM) channels comprising: a nonlinear medium, wherein the nonlinear medium comprises one or more highly-nonlinear fiber (HNLF) sections adapted to receive multiple WDM channels from the input, and wherein further the HNLF sections are separated by one or more periodic-group delay devices (PGDDs). The all-optical processor may also include one or more amplifiers adapted to receive the multiple WDM channels; one or more de-interleavers adapted to separate the WDM channels into one or more sets of WDM channels, one or more optical band-pass filters to filter the channels received from the amplifier; one or more optical band-pass filters to filter the channels received from the non-linear medium; and one or more interleavers to receive the filtered channels from the periodic band-pass filter and to combine the sets of WDM channels into an output.

Abstract: A method and system for transmitting information in an optical communication system includes modulating a non-intensity characteristic of an optical carrier signal with a data signal to generate an optical information signal. The optical information signal is transmitted over an optical link. The optical information signal is amplified over a length of the optical link with a co-launched amplification signal traveling in the optical link in a same direction as the optical information signal.

Abstract: A group delay compensation equalizer is disclosed that employs a single channel four-port WDM device for compensating the group delay experienced by a plurality of wavelengths transmitted over different paths. The transmission differential between two wavelengths is compensated by transmitting the two wavelengths through two different paths where the fiber length in reflecting the second wavelength is equal to the transmission time difference between the two wavelengths. The single channel four-port group delay equalizer effectively provides a unidirectional signal flow, as compared to the conventional equalizer that transmits optical signals bi-directionally. The present invention reduces the cost of a group delay equalizer by simplifying the use of multiple three-port WDM devices into a single channel four-port WDM device.

Abstract: A wavelength converter for binary optical signals includes an interferometer structure (110) for generating an output signal by modulating a received local signal (LS) according to the modulation of a fUrther received first input signal (IS 1). When such interferometer structures (110) are operated in a standard mode it is known in the art to control the power of the input signal such that the extinction ratio of the output signal is kept minimal. The invention also controls the power of the input signals to achieve the minimal extinction ratio when the wavelength converter and in particular the interferometer structure (110) is operated in a differential mode receiving two input signals.

Abstract: An optical wavelength converter receives an input optical signal, and in response, generates an output optical signal having a wavelength that is different from the wavelength of the received input signal. An optical amplifier amplifies the received input signal and delivers the amplified signal to an optical splitter adapted to split the amplified signal into two identical optical signals. An optical multiplexer receives one of the split signals as well as a continuous wave optical signal to generate a combined signal. An semiconductor optical amplifier receives the combined signal at its first side, and the other one of the split signals at its second side. The output signal is generated as a result of a counter-propagating four-wave mixing occurring within the semiconductor optical amplifier. This output signal has the same wavelength as the continuous-wave signal and has an amplitude modulation that is identical to the amplitude modulation of the input signal.

Abstract: The field of the invention is that of devices for regenerating optical signals. It applies more particularly to systems for high-throughput long distance transmission by optical fibres of digital data. While propagating, optical signals necessarily experience attenuation and degradation of their signal/noise ratio. To compensate for these degradations, wholly-optical regeneration devices are generally used. The object of the invention is to ensure regeneration which in large part eliminates noise, without using auxiliary optical devices. This regeneration is ensured by a structure with saturable optical absorbent comprising an optical cavity of thickness L comprising at least one layer of active material of Henry factor ?H and of maximum absorption variation ?? such that the thickness L equals about 2?/(?H, ??).

Abstract: A regenerator for restoring the originally encoded optical phase of a differential-phase-shift-keyed signal. In an embodiment, the regenerator simultaneously provides limiting amplification and reduces amplitude noise based on a phase-sensitive optical amplifier that combines a weak signal field of a degraded input data with a strong pump field supplied by a local oscillator in a nonlinear interferometer. The two fields interact through degenerate four-wave mixing, and optical energy is transferred from the pump to the signal and vice versa. The phase sensitive nature of the optical gain leads to amplification of a specific phase component of the signal, determined by the input pump-signal phase difference and the incident signal phase is restored to two distinct states, separated by 180° according to the original encoding. Simultaneously, gain saturation of the pump wave by the signal wave results in limiting amplification of the signal wave for removing signal amplitude noise.

Abstract: The present invention is a method of processing an optical signal, including the steps of (a) inputting signal light into a first nonlinear optical medium to broaden the spectrum of the signal light through self phase modulation occurring in the first nonlinear optical medium, thereby obtaining first spectrally broadened light, (b) compensating for chromatic dispersion effected on the first spectrally broadened light obtained in the step (a), and (c) inputting the first spectrally broadened light processed by the step (b) into a second nonlinear optical medium to broaden the spectrum of the first spectrally broadened light through self phase modulation occurring in the second nonlinear optical medium, thereby obtaining second spectrally broadened light.

Abstract: In a system connecting a transmitter and a receiver using transmission paths and repeaters (in-line amplifiers), red chirping whose ? parameter is performed for an optical signal on a transmitting side. Each of the repeaters includes a dispersion-compensator for compensating the amount of dispersion on a preceding transmission path. The amount of dispersion compensation of the dispersion-compensator included in the transmitter is made constant. The dispersion-compensator included in the receiver is arranged in order to compensate the amount of dispersion on a preceding transmission path. A spread of a pulse width on a transmission path can be efficiently compensated by using the compensation capability of the dispersion-compensators and the red chirping on the transmitting side.

Abstract: A multi-wavelength light source unit for optical communication system is disclosed. The light source includes a demultiplexer for demultiplexing a multiplexed light signal into a plurality of lights having different wavelengths and a multiplexer that receives the demultiplexed lights and multiplexes the demultiplexed lights into the multiplexed light signal. Input ports of the multiplexer are respectively port-to-port connectable to each one of a plurality of output ports of the demultiplexer. The light source unit includes a plurality of semiconductor optical amplifiers amplifying the demultiplexed lights output form the demultiplexer, and a plurality of beam splitters for splitting the amplified demultiplexed lights into two parts, so as to provide the respective input ports of the multiplexer with a split part of the lights, while to transmit the other part of the lights out of the beam splitters.

Abstract: Conventionally, an adjustment of an optical power level of an input Pin of an optical amplifier module is made with an optical variable attenuator. An optical coupler for measuring the optical power level of Pin and an optical variable attenuator are replaced by a variable optical coupler. The branch ratio of the variable optical coupler is varied, whereby the input optical power level Pin to an optical amplifier module is adjusted. As a result, an optical loss is reduced by an amount corresponding to the elimination of the optical attenuator, and also the OSNR of the optical amplifier module is improved.

Abstract: A wavelength division multiplexing system includes a wavelength division multiplexing transmission path including a multimode optical fiber that is codoped with germanium and fluorine. The wavelength division multiplexing system may further include a multiplexer and a demultiplexer, in which the multiplexer and the demultiplexer are coupled via the multimode optical fiber. The wavelength division multiplexing system may further include a first multiplexer/demultiplexer and a second multiplexer/demultiplexer, in which the first multiplexer/demultiplexer and the second multiplexer/demultiplexer are coupled via the multimode optical fiber so that a bidirectional wavelength division multiplexing is enabled.

Abstract: A system, method and device for AO2R is presented. The AO2R system presented is redundant, containing multiple pathways for the input and output signals to travel. The system carries out both the regeneration and reshaping functions in the optical domain, and returns a clean output signal at the same bit rate and in the same format as the input signal, on a wavelength of choice. As an all optical device, the apparatus is bit rate and format transparent, and requires no optical-electrical-optical conversion. The system's built in redundancy and symmetry allows less than perfect yields on components to be tolerated, thus increasing the utility of devices manufactured with less than perfect yields. In alternative embodiments the redundancy aspect of the invention can be extended to any optical signal processing device, thus facilitating high availability optical signal processing.

Abstract: A method and system for transmitting information in a wavelength division multiplex (WDM) or other suitable multichannel optical communication system includes receiving a multichannel signal having a symbol rate and comprising a plurality of non-intensity modulated optical information signals. The non-intensity modulated optical information signals have a minimum channel spacing comprising a multiple of the symbol rate within 0.4 to 0.6 of an integer. The non-intensity modulated optical information signals are separated from the multichannel signal and each converted into an intensity modulated optical information signal using an asymmetric interferometer. A data signal is recovered from the intensity modulated optical information signal.

Abstract: The invention relates to a saturable light absorber adapted to receive different focused spectral components, wherein the structure of said saturable light absorber comprises microcavities integrated into a substrate and each associated with a respective one of said spectral components, each microcavity comprising a saturable absorber layer delimited by a top reflector and a bottom reflector and being disposed and having dimensions such that it receives only the focused spectral component associated with it.

Abstract: A digital signal channel bypass is provided as bypass around an optical network optical amplifier, in particular, an analog type optical amplifier, such as an EDFA, in an optical transport network or system. The digital signal bypass provides for an ability to maintain the existing optical amplifier OO amplification site while inserting a bypass that provides ultra low-cost OEO REGEN in a digital optical network (DON) utilizing both semiconductor electronic integrated circuit chips and semiconductor photonic integrated circuit (PIC) chips where all the optical components are in semiconductor integrated chip form providing 1R, 2R, 3R or 4R regeneration as well as other signal caring functionality. A salient feature of the digital signal bypass is to regenerate signals in the optical span that are outside the gain bandwidth of the EDFA or other such amplifier.

Abstract: The invention provides an optical communication system (10) comprising a plurality of mutually interconnected bi-directional optical waveguide rings (20, 30, 40, 50, 60) in which radiation modulated with communication traffic propagates. The radiation is partitioned into 32 distinct wavebands. Interfaces (70, 80, 90, 100, 110, 120) are included in the system (10) where communication traffic propagating in the rings transfers from one ring to another. Each interface (70) is capable of providing an all-optical waveband reconfigurable communication link between the rings (20, 30, 40, 50, 60). At each interface (70), conversion of optical radiation to corresponding electrical signals is not required when transferring communication traffic from one ring to another, thereby providing the system (10) with a potentially larger communication bandwidth compared to conventional optical communication systems.

Abstract: High power repeaters for use in amplifying optical data signals transmitted through undersea fiber optic cables are disclosed. Raman amplification schemes using 100 or more pump lasers are integrated into industry standard sized pressure vessels for amplifying optical data signals transmitted through one or more fiber optic pairs. Other repeater features include high density packaging, efficient power distribution, and component sharing.

Abstract: This invention provides a dynamic interconnection system which allows to couple a pair of optical beams carrying modulation information. In accordance with this invention, two optical beams emanate from transceivers at two different locations. Each beam may not see the other beam point of origin (non-line-of-sight link), but both beams can see a third platform that contains the system of the present invention. Each beam incident on the interconnection system is directed into the reverse direction of the other, so that each transceiver will detect the beam which emanated from the other transceiver. The system dynamically compensates for propagation distortions preferably using closed-loop optical devices, while preserving the information encoded on each beam.

Abstract: A repeater apparatus (1001) is constituted from infrared transmitter sections (1s, 2s, 3s) and infrared receiver sections (1r, 2r, 3r) as well as connection control sections (1C, 2C, 3C) and further a repeater section (101), thereby attaining independent communications with the individual one of several associated equipments with respect to infrared communication apparatus of the direct emission type which supports only one-to-one (1-to-1) or one-to-several (1-to-N) communication schemes, thus enabling achievement of N-to-N communication forms by performing transfer of data information being received by each communication equipment to others.

Abstract: An optical regenerator enabling matching of self-phase modulation induced spectral broadening and optical regenerator filter center wavelengths and bandwidths for different fiber dispersion values. The regenerator monitors the central part of an input signal spectrum at the output of a non-linear medium and suppresses the power at the center wavelength to allow for a constant spectral broadening for different fiber dispersion values. The regenerator utilizes a control filter to control a variable amplifier via a feedback loop, and the variable amplifier adjusts the power of the signal launched into the non-linear medium to ensure a sufficient self-phase modulation broadened spectrum.

Abstract: An optical repeater is provided between a first optical fiber transmission path and a second optical fiber transmission path having a zero-dispersion wavelength different from the first optical fiber transmission path. This optical repeater wave-converts a wavelength division multiplex signal input from the first optical fiber transmission path with respect to respective wavelengths thereof, and outputs the wave-converted signal to the second optical fiber transmission path.

Abstract: The present invention relates to an optical communication apparatus for detecting the intensity of light in an optical modulator or the intensity of a modulation signal and for controlling the operating point of the optical modulator based on the result of detection. In the optical communication apparatus having such a configuration, the operating point of the optical modulator can be kept stable even when the input light or the modulation signal is temporarily non-existent in the optical communication apparatus.

Abstract: An optical component array allowing expansion of the occupied bandwidth on an existing optical transmission network without disrupting signal traffic. Wavelength selective filters (16, 30; 20, 34) and optical components, such as amplifiers (18, 32) are arrayed for use with a wavelength division multiplexed optical transmission system to transmit a selected portion of a transmission spectrum to an amplifier path and reflect the remainder of the spectrum. Wavelength selective filters and associated amplifiers are arranged in a cascade configuration with a bypass path (35, 37). Additional wavelength selective filters and amplifiers can be added in the bypass path without disrupting existing signal traffic, and such additions can provide for a remaining bypass path, thus allowing further expansion. This configuration provides an expandable amplifier array with a low initial cost.

Abstract: The present invention provides an all-optical dynamic gain equalizer of an open-loop design using nonlinear optical materials for equalizing channel power without the need of complex electronics and close-loop control, and provides pulse reshaping and in some embodiments noise reduction at no extra cost. The invention achieves restoration of spectral power uniformity by employing nonlinear optical limiters with desirable power transfer function curves to each of the optical signals to be equalized. The invention provides the highly desirable functions of dynamic gain equalization, and optical pulse reshaping. Some embodiments constructed according to the invention provide signal dynamic range control by biasing the nonlinear optical limiter with a biasing optical signal.

Abstract: A method and device is disclosed for dispersion compensation of an optical signal having periodic dispersion within a multi-channels system. For example interleaved optical channels often exhibit dispersion having a characteristic that is repeated in adjacent channels. By providing a periodic device in the form of a multi-cavity GT etalon having a free-spectral range that corresponds to the channel spacing the dispersion in the interleaved signal can be lessened and practically obviated or balanced to a desired level. Advantageously, the input and output angle of the signal can be varied to provide fine tuning. This invention provides a device and method to achieve that end.

Abstract: An AOTF drive method for driving a plurality of AOTFs connected in tandem comprises: separating a plurality of RF signals in advance into a plurality of groups; batch-branching the RF signals of each group in accordance with the number of steps of the AOTFS; and batch-adjusting the phases of the individual branched RF signals. As a result, this makes it possible to reduce the number of phase shifters compared to the prior art while maintaining the effectiveness of suppressing beats in the AOTFs.

Abstract: A lightwave communication system is provided that includes first and second optical transmitters/receivers remotely located with respect to one another. First and second optical transmission paths couple the first transmitter/receiver to the second transmitter/receiver for bidirectionally transmitting optical information therebetween. First and second doped optical fibers are respectively disposed in the first and second optical transmission paths. Optical pump energy is supplied by first and second optical pump sources. The first optical pump source generates Raman gain in the first transmission path and the second optical pump source generates Raman gain in the second transmission path. A first optical coupler is provided for optically coupling pump energy from the first pump source to the second-doped optical fiber and a second optical coupler is provided for optically coupling pump energy from the second pump source to the first doped optical fiber.

Abstract: An optical regenerator enabling matching of self-phase modulation induced spectral broadening and optical regenerator filter center wavelengths and bandwidths for different fiber dispersion values. The regenerator monitors the central part of an input signal spectrum at the output of a non-linear medium and suppresses the power at the center wavelength to allow for a constant spectral broadening for different fiber dispersion values. The regenerator utilizes a control filter to control a variable amplifier via a feedback loop, and the variable amplifier adjusts the power of the signal launched into the non-linear medium to ensure a sufficient self-phase modulation broadened spectrum.

Abstract: An optical communication system is provided that includes first and second optical transmitters/receivers remotely located with respect to one another and which are coupled together by first and second optical transmission paths for bidirectionally transmitting optical information therebetween. First and second optical amplifiers are respectively disposed in the first and second optical transmission paths. At least one loop-back path optically couples a portion of a WDM optical signal from the first to the second transmission path. The loop-back path includes a filter for transmitting a monitoring channel but not a data channel included in the optical signal portion traversing the loop-back path.

Abstract: An optical transmission system includes a first transmitter unit and a first receiver unit. A first optical transmission path interconnects the first transmitter unit and the first receiver unit. The first optical transmission path is defined by at least three transmission spans. The first optical transmission path has a periodic dispersion map with a first periodic component comprising a fixed portion and an adjustable portion, and a second periodic component greater in length than the first periodic component. The fixed portion of the first periodic component of the periodic dispersion map is provided by the respective transmission spans. A plurality of optical repeaters each optically couple adjacent ones of the transmission spans to one another. A first plurality of adjustable dispersion trimming element are each located in one of the optical repeaters and optically couples one of the transmission spans to an optical amplifier located in the optical repeater.

Abstract: The invention provides for optical circulators which redirect light from port to port sequentially in one direction used to separate traffic in a bidirectional optical fiber transmission system. The invention provides for using two optical circulators in each span of bidirectional fiber so that the OSC channel can be transmitted in one direction opposite to the WDM channels.

Abstract: An amplifier including a first input for a first at least two input signals having mutually distinct wavelengths, a first output for a first at least two output signals, the first at least two output signals having said mutually distinct wavelengths, a first circulator including an input port coupled to the first input, an output port coupled to the first output, and an intermediate port coupled to a first end of a selective reflection circuit, and, a second circulator including an intermediate port coupled to a second end of the selective reflection circuit, an output port coupled to a first selective splitter, and an input port coupled to a second selective splitter, wherein the first selective splitter and the second selective splitter are centered about a first selected wavelength amongst the mutually distinct wavelengths.

Abstract: An optical communication system (20) is provided for transmitting a multi-rate data signal between a transmitter (22) and a receiver (24) in a power efficient manner. The optical communication system (20) includes an optical source (32) that supplies an optical carrier signal; an encoder (44) that receives and encodes a data signal; an external phase modulator (42) that modulates the optical carrier signal with the encoded data signal, such that the modulator (42) varies the duty factor of the modulated optical signal based on the encoded data signal; and an optically saturated erbium doped fiber amplifier (36) that amplifies the modulated optical signal prior to transmission by the transmitter (22). In accordance with the present invention, the modulation scheme of the optical communication system (20) varies the duty cycle of the modulation to attain power efficiency during periods of low data demand.

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: A wireless optical communication system can reduce the power consumption needed for light emission by a controlled node and suppress a modulated signal component, other than the modulated signal of input data for transmission, in the modulated signal components carried by the light output of the controlled node. The controlled node includes a transmission device for transmitting input data for transmission by an infrared ray amplitude-modulated by a modulated signal of a first frequency band and a light emission control device for suspending the light emission by the transmission device for a predetermined period based on a data amount of the input data for transmission. The light emission circuit generates a light emission control signal and the transmission device stops or starts the light emission based on the light emission control signal so that the modulated signal component in the second frequency band other than the first frequency band does not exceed a maximum allowable value.

Abstract: A high-capacity optical transmission arrangement utilizing a plurality of laser sources and a plurality of wide-band optical amplifiers permit the reliable transmission of 1 Tb/sec rates over significant distances of optical fiber.