Abstract: An O-band optical communication system includes a transmitter, a receiver, and an optical fiber system coupled between the transmitter and the receiver. The optical fiber system includes at least a first fiber segment, with a positive dispersion-wavelength gradient and a first zero dispersion wavelength, coupled in series to a second fiber segment, with a negative dispersion-wavelength gradient and a second zero dispersion wavelength. When an optical signal propagating along the first fiber segment has a wavelength shorter than the first zero dispersion wavelength and experiences negative dispersion, at least partial positive dispersion compensation is provided by propagation along the second fiber segment. When light of the optical signal propagating along the first fiber segment has a wavelength longer than the first zero dispersion wavelength and experiences positive dispersion, at least partial negative dispersion compensation is provided by propagation along the second fiber segment.

Abstract: An optical fiber transmission system and method for using the system are provided. The system may include a span of transmission fiber for transmitting light signals through the optical fiber transmission system. The system may include a dispersion compensating module coupled to the span of transmission fiber. The system may include a switchable module including a set of selectable light signal paths, the set of selectable light signal paths including at least one path through a dispersion compensating element. The system may include a processor coupled to the switchable module for selectively monitoring the set of selectable light signal paths, where the processor is further configured to derive a metric based on the set of selectable light signal paths for controlling the dispersion compensating module.

Abstract: Non-contact methods of predicting an insertion loss of a test optical fiber connector are disclosed. Light is sent down the at least one optical fiber of the connector in the fundamental mode to emit an output light beam. The output-beam image is captured at different distances from the fiber end faces to define multiple output-beam images each associated with one of the multiple measurement positions. A Gaussian curve is then fitted to the multiple output-beam images to determine a mode field diameter, an offset, and a tilt of the output light beam. A Gaussian field model that incorporates the offset, the tilt, and the mode-field diameter is then used to predict the insertion loss when connecting to a reference optical fiber of a reference optical fiber connector.

Abstract: A transmitter (1) is configured to transmit an optical signal, the transmitter comprising an optical dispersion compensator (10) configured to compensate for chromatic dispersion of the optical signal. The optical dispersion compensator comprises a plurality of delay elements (20; 40). The plurality of delay elements (20; 40) have a combined response providing a delay to the transmitted optical signal which varies with frequency.

Abstract: The present invention is directed to communication systems and methods. In a specific embodiment, the present invention provides an optical receiver that receives a data stream from an optical transmitter. The optical receiver determines a histogram contour parameter using the data stream and inserts the histogram contour parameter into a back-channel data segment, which is then transmitted to the optical transmitter. The optical transmitter changes its data transmission setting based on the histogram contour parameter. There are other embodiments as well.

Abstract: An O-band optical communication system includes a transmitter, a receiver, and an optical fiber system coupled between the transmitter and the receiver. The optical fiber system includes at least a first fiber segment, with a positive dispersion-wavelength gradient and a first zero dispersion wavelength, coupled in series to a second fiber segment, with a negative dispersion-wavelength gradient and a second zero dispersion wavelength. When an optical signal propagating along the first fiber segment has a wavelength shorter than the first zero dispersion wavelength and experiences negative dispersion, at least partial positive dispersion compensation is provided by propagation along the second fiber segment. When light of the optical signal propagating along the first fiber segment has a wavelength longer than the first zero dispersion wavelength and experiences positive dispersion, at least partial negative dispersion compensation is provided by propagation along the second fiber segment.

Abstract: An optical signal transmission system and method of allocating center frequencies of intermediate frequency (IF) carriers in a frequency division multiplexing (FDM) optical fiber link. The optical signal transmission method includes determining a center frequency interval between modulated signals based on a bandwidth of the modulated signals or a center frequency of a modulated signal having a lowest center frequency, among the modulated signals, reallocating center frequencies to the modulated signals based on the center frequency interval between the modulated signals, and converting the modulated signals reallocated the center frequencies from electrical signal into optical signal and transmitting the optical signal.

Abstract: An undersea long-haul transmission system includes an optical fiber transmission span and a coherent detection and digital signal processing module for providing dispersion compensation. The transmission span includes at least one fiber pair comprising substantially equal lengths of a positive-dispersion first fiber and a negative-dispersion second fiber that are configured to provide a signal output at transmission distances greater than 10,000 km, in which the combined accumulated dispersion across the operating bandwidth does not exceed the dispersion-compensating capacity of the coherent detection and digital signal processing module. Further described is a fiber for use in an undersea long-haul transmission span. At a transmission wavelength of 1550 nm, the fiber has a dispersion coefficient in the range of ?16 to ?25 ps/nm·km, and a dispersion slope in the range of 0.04 to 0.02 ps/nm2·km.

Abstract: A communication system includes a transmission path through which an optical signal is propagated; and dispersion slope imparting sections provided on a transmitting side and a receiving side of the transmission path, the dispersion slope imparting sections imparting different dispersion and dispersion slope characteristics in accordance with a wavelength band of the optical signal, wherein the dispersion and dispersion slope characteristics imparted by the dispersion slope imparting section on the transmitting side is different from those on the receiving side.

Abstract: A method is provided for carrying out dispersion compensation in an optical mesh network supporting simultaneously traffic services being provided at two or three different bit rates including a basic bit rate being 10 Gbps and at least one higher bit rate selected from among 40 Gbps and 100 Gbps. The method comprises the following steps: providing in-line dispersion compensation for every span in the network so as to reach positive average residual dispersion RDS per span extending to less than about 3 km; providing start points of possible trails in the network with respective external, pre-compensation negative Dispersion Compensation modules (DCMs), and providing termination points of possible trails in the network with respective external post-compensation positive DCMs.

Abstract: The present invention provides a wavelength division multiplexing system and a method and device for its residual dispersion compensation, wherein the device for residual dispersion compensation of wavelength division multiplexing system comprises: a performance parameter detecting device for receiving and detecting performance parameter of receiving terminal optical signal and sending detecting result of the performance parameter to a central control device; the central control device for deciding a dispersion regulating mode of a tunable dispersion compensator according to the detecting result of the performance parameter and sending the dispersion regulating mode to a tunable dispersion compensator control device through control signaling; and the tunable dispersion compensator control device for receiving the control signaling sent by the central control device and adjusting dispersion compensation amount of the tunable dispersion compensator according to the control signaling in order to make residual di

Abstract: The present wavelength multiplexed optical system includes a multimode optical fiber that transmits wavelength multiplexed optical signals and a plurality of multimode modal dispersion compensation optical fibers. Each modal dispersion compensation optical fiber can transmit one of the multiplex wavelengths, and each modal dispersion compensation optical fiber has an optimized index profile such that the modal dispersion for the transmitted wavelength is approximately inversely equal to the modal dispersion induced in the multimode optical fiber. The wavelength multiplexed optical system facilitates an increased bitrate without reducing bandwidth.

Abstract: The present disclosure provides systems and methods for the compensation of signal distortion in fiber optic communication systems and the like. More specifically, the present disclosure provides an orthogonal polarization detection and broadband pilot (OPDBP) technique for the compensation of nonlinear cross polarization (i.e. nonlinear cross polarization modulation) (XPolM) induced noise and nonlinear nonlinear cross phase modulation (XPM) induced noise in a high data rate polarization multiplexed (PM) multilevel-quadrature amplitude modulated (M-QAM) channel due to neighboring channels. This approach allows for the compensation of both XPolM and XPM simultaneously, providing several dBs of optical reach extension. The approach uses a pilot tone based orthogonal polarization detection scheme with broadband (i.e. a few GHz wide) filtering of the pilot tones.

Abstract: Exemplary embodiments include a method and systems for impairment compensation in a communication system. The systems can include an electronic phase conjugation system that receives an incoming optical signal from a first section of a fiber optic link, converts the incoming optical signal to an in-phase electric signal and a quadrature electrical signal, and generates a phase conjugated outgoing optical signal from the in-phase and quadrature electrical signals. The phase conjugated outgoing optical signal compensates for impairment of the fiber in the communication system.

Abstract: An embodiment of the invention includes a tunable optical dispersion compensator (TODC) comprising a first beam displacer on an optical path, wherein the first beam displacer separates an optical signal into a first beam and a second beam, and one or more polarizing beam splitters on the optical path, wherein the one or more polarizing beam splitters keep the first beam and the second beam on the optical path. The TODC also comprises one or more etalons on the optical path, wherein the one or more etalons are tunable to introduce a group delay in the first beam and the second beam, and a reflecting mirror on the optical path, wherein the reflecting mirror returns the optical signal back along the optical path. The TODC further comprises a second beam displacer, wherein the second beam displacer combines the first beam and the second beam into an output optical signal.

Abstract: Methods, apparatuses, and systems are presented for performing adaptive equalization involving receiving a signal originating from a channel associated with inter-symbol interference, filtering the signal using a filter having a plurality of adjustable tap weights to produce a filtered signal, and adaptively updating each of the plurality of adjustable tap weights to a new value to reduce effects of inter-symbol interference, wherein each of the plurality of adjustable tap weights is adaptively updated to take into account a constraint relating to a measure of error in the filtered signal and a constraint relating to group delay associated with the filter. Each of the plurality of adjustable tap weights may be adaptively updated to drive group delay associated with the filter toward a target group delay.

Abstract: The present disclosure relates to dispersion slope compensation and dispersion map management systems and methods in an optical network utilizing a reconfigurable optical add-drop multiplexer (ROADM) with a plurality of different values of dispersion compensation modules (DCMs). The DCMs form a dispersion compensation ladder at certain intermediate nodes in the optical network to provide dispersion slope compensation and dispersion map management. The reconfigurable routing structure of the ROADM enables these intermediate nodes to route individual wavelengths to any one of the DCMs as required for the particular path of the wavelength. Advantageously, the present invention removes the requirement for banded compensation at receiver nodes and allows for dispersion map management at intermediate points along a fiber route as opposed to bulk compensation at the receiver.

Abstract: An optical communication device comprises a variable dispersion compensator, a photoelectric converter, and a processor. The variable dispersion compensator compensates an amount of wavelength dispersion of an optical signal received from an optical transmission line. The photoelectric converter converts the compensated optical signal into an electrical signal. The processor is operative to extract a frequency of the converted electrical signal, and to discriminate bit information of the electrical signal based on the frequency extracted using a decision phase and a decision threshold. The processor is operative to detect bit error information that is information related to an error of the discriminated bit information, and to control the amount of wavelength dispersion based on the detected bit error information.

Abstract: A system may include a first measurement device configured to be coupled to a first node in an optical path being measured. The first measurement device may be configured to generate a signal at an initiating device; identify an unused channel in an optical path, wherein the optical path includes at least two spans; and transmit the signal on the unused channel. A second test device may be configured to be coupled to a last node in the optical path being measured. The second measurement device may be configured to: receive the signal at a destination device; compensate the signal for chromatic dispersion (CD) and/or polarization mode dispersion (PMD) effects; and determine CD and/or PMD measurements associated with the optical path being measured based on the compensation.

Abstract: An optical amplifier module includes a first optical amplifier to amplify main signal light to be supplied to a dispersion compensation fiber (DCF), a second optical amplifier to amplify the main signal light supplied from the DCF, a generating part to generate monitoring light having a wavelength longer than a wavelength of the main signal light, a multiplexing part to multiplex the monitoring light generated by the generating part and the main signal light to be supplied to the DCF, a demultiplexing part to demultiplex the monitoring light from the main signal light supplied from the DCF, and a detection part to detect a light intensity of the monitoring light demultiplexed by the demultiplexing part.

Abstract: A distortion compensating apparatus which compensates for distortion in a waveform of a received light signal through a digital signal processing includes a plurality of fixed amount compensators which compensate for the distortion in the waveform at respective given compensating amounts. The combination of operating states of the plurality of fixed amount compensators is changed by on/off switching of each of the plurality of fixed amount compensators, and the plurality of fixed amount compensators are cascaded.

Abstract: An optical dispersion compensator including a first optical device in which light inputted from a first port is outputted from a second port and light inputted from the second port is outputted from a third port, an optical filter type dispersion compensation device that receives light from the second port of the first optical device and compensates wavelength dispersion with respect to the received light, and a second optical device that includes a fourth port to which light is inputted from the optical filter type dispersion compensation device, and in which the light inputted from the fourth port is outputted from a fifth port and light inputted from a sixth port is outputted from the fourth port.

Abstract: A method reduces time-varying polarization crosstalk due to XPolM by transmitting multi-dimensional orthogonal constellations. Three variants of crosstalk-free constellations are provided: Grassmann constellations, unitary constellations, and rotation codes. The method uses the Grassmann constellations and the unitary constellations to deal with fiber nonlinearity by applying as a polarization-time coding. The rotation codes exploit a fiber channel characteristic to improve performance and to reduce computational complexity. The underlying orthogonality behind those constellations enables the receiver to decode it as if there is no polarization crosstalk. Moreover, the required computational complexity at the receiver is significantly reduced because neither crosstalk cancellers nor channel estimators are needed.

Abstract: Regarding an optical pulse reshaping device of CPF type, there are subjects to reduce the number of stages by enhancing a compression efficiency as extremely higher for one stage of the CPF with maintaining a quality of an output pulse as high, and to be able to improve a degree of multiplexing by obtaining an output pulse having a Gaussian function for both of a time waveform therefor and a frequency waveform therefor. By using a normal dispersion HNLF in place of a zero dispersion HNLF, which configures the conventional CPF, it becomes able to overcome the above mentioned subjects. Moreover, it becomes able to reduce the number of fusion splice for a fiber, and to reduce a propagation loss of the CPF, by enhancing the compression efficiency as higher.

Abstract: A signal equalizer for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments.

Abstract: A dispersion compensation device includes: an optical branching unit to branch an optical signal to be received; a first dispersion compensator to perform dispersion compensation on one part of the optical signal branched by the optical branching unit with a variable compensation amount; a second dispersion compensator to perform dispersion compensation on another part of the optical signal branched by the optical branching unit; a monitoring unit to monitor the communication quality of an output optical signal of the second dispersion compensator; and a controlling unit to determine the direction of variation in chromatic dispersion of the optical signal based on the direction of variation in communication quality monitored by the monitoring unit and control the compensation amount of the first dispersion compensator based on the result of the determination.

Abstract: A method reduces time-varying polarization crosstalk due to XPolM by transmitting multi-dimensional orthogonal constellations. Three variants of crosstalk-free constellations are provided: Grassmann constellations, unitary constellations, and rotation codes. The method uses the Grassmann constellations and the unitary constellations to deal with fiber nonlinearity by applying as a polarization-time coding. The rotation codes exploit a fiber channel characteristic to improve performance and to reduce computational complexity. The underlying orthogonality behind those constellations enables the receiver to decode it as if there is no polarization crosstalk. Moreover, the required computational complexity at the receiver is significantly reduced because neither crosstalk cancellers nor channel estimators are needed.

Abstract: A method for reducing cross-phase modulation in an optical signal includes receiving an optical signal comprising a plurality of channels, wherein the information being communicated in a first set of one or more of the channels is modulated using one or more single-polarization modulation techniques and wherein the information being communicated in a second set of one or more of the channels is modulated using one or more dual-polarization modulation techniques. The method also includes splitting the optical signal into at least a first copy of the optical signal and a second copy of the optical signal and terminating the second set of channels in the first copy. Furthermore, the method includes applying a differential group delay to the second copy, the differential group delay introducing a walk-off between symbols communicated in a first polarization component of the second set of channels and the symbols of a second polarization component of the second set of channels.

Abstract: A method may include generating a signal at an initiating device. A channel in an optical path may be identified, with the optical path including at least two spans. Simulated polarization mode dispersion (PMD) is injected into the signal to generate a test signal. The test signal is transmitted on the channel and received at a destination device. PMD effects in the test signal are compensated, and a measurement of PMD for the test signal is determined based on the compensation, the PMD for the test signal including PMD for the channel and the injected PMD. A measurement of the PMD for the channel is determined based on the PMD for the test signal and the injected PMD.

Abstract: An apparatus for generating a dispersion compensation signal includes a splitting module for splitting a data signal to be transmitted into N channels of data signals; N pre-processing modules for adjusting in frequency domain the phases and amplitudes of the N channels of data signals and outputting N channels of pre-warped electrical signals; an optical carrier generating module for generating N channels of coherent optical carriers; N electro-optic modulators for modulating the N channels of coherent optical carriers based on the N channels of pre-warped electrical signals and generating N channels of pre-warped optical signals; an optical coupling module for coupling the N channels of pre-warped optical signals into a dispersion compensation optical signal. By pre-processing the data signals, the present disclosure may allow the use of existing devices to generate a dispersion compensation signal so that the bandwidth requirement set by prior art on the electrical device is reduced.

Abstract: A method and apparatus for producing a series of amplified optical pulses from a series of input optical pulses. The method includes creating a set of local optical pulses from a series of input optical pulses, the set of local optical pulses being applied to the input of an optical amplifier and having different amplitudes arranged in a graded order. The set of local optical pulses are amplified by an optical amplifier to have a significantly amplified first local optical pulse that is removed from the set of local optical pulses and output as a part of the series of amplified optical pulses. After removing the significantly amplified first local optical pulse, the set of local optical pulses is recreated by adding a new optical pulse from the series of input optical pulses to the end of the set of local optical pulses; and the recreated set of local optical pulses is routed back to be applied to the input of the optical amplifier to continue producing the series of amplified optical pulses.

Abstract: A method and system for processing analog optical signals to produce a single RF output free from even-order harmonic distortion. Two analog optical signals of different wavelengths ?1, ?2 are input into a dual-output Mach-Zehnder modulator (MZM), where one wavelength input is high-biased and one wavelength is low-biased. The complementary high- and low-biased wavelengths are output from each arm of the MZM to a multiplexer, which filters out the unwanted high- or low-biased wavelengths from each MZM arm so that both wavelengths are low-biased or high-biased. The signals are passed to a pair of photodiodes, and the photocurrents from the photodiodes are differenced to produce the final RF output. Because of the complementary phase differences between the two low- or high-biased signals generating the photocurrent, all components of the photocurrent except the fundamental and odd-order harmonics cancel each other, resulting in a high-quality RF output free from harmonic distortion.

Abstract: Dispersion may be managed in an optical network by allowing accumulation of dispersion to at least ten thousand ps/nm, and several tens of thousands of ps/nm in some embodiments. The accumulated dispersion may be returned to zero or near zero at a receiver and/or at one or more branch paths coupled to the transmission path.

Abstract: An optical signal processing device includes a waveform width widening unit configured to widen a waveform width of an optical signal; and an optical limiter circuit, to which the optical signal the waveform width of which is widened is input, configured to suppress an intensity of the optical signal in a region where an input intensity and an output intensity are not proportional.

Abstract: Dispersion compensation is provided in an optical transmission system. An optical line couples first and second transceivers, and a plurality of amplifiers coupled to the optical line are spaced throughout the optical line with variable span distances. A plurality of dispersion compensation modules include a coarse granularity fiber, a connector, and a fine granularity fiber. A memory is associated with the dispersion compensators to provide information related to the value of the dispersion compensation.

Abstract: According to an aspect of an embodiment, an apparatus includes: a wavelength-to-transmission quality characteristic obtaining unit for obtaining a wavelength-to-transmission quality characteristic; a residual dispersion-to-transmission quality characteristic saving unit for saving a residual dispersion-to-transmission quality characteristic; a wavelength-to-residual dispersion characteristic generating unit for generating a wavelength-to-residual dispersion characteristic from a relationship between the wavelengths of the other channels and the residual dispersion based on the wavelength-to-transmission quality characteristic and the residual dispersion-to-transmission quality characteristic; a variable dispersion compensator for providing variable dispersion compensation to another channel,; and a variable dispersion compensation controlling unit for performing setting control on a dispersion compensation amount.

Abstract: A signal equalizer for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments.

Abstract: A method for cost-effective optical transmission with fast Raman tilt or other transient event control uses a combination of Erbium-doped fiber amplifiers (EDFAs) and Raman fiber amplifiers (RFAs), where EDFAs are used as the primary optical amplifiers to compensate the span loss while the RFA (advantageously a forward-pumped RFA) is used only in some specific spans with a feed-forward control circuit serving as a fast Raman tilt transient compensator, the RFA also serving as an optical amplifier. A long haul optical transmission system using feed-forward controlled RFA's periodically spaced along its length, for example, when add-drop multiplexing is used, makes full use of the economics of EDFAs and the fast tilt transient control capability of a RFA enabled by an adjustable speed feed-forward or feed-back control technique.

Abstract: An optical transmission system employs an optical fiber as an optical transmission path that includes a holey fiber and a dispersion-compensating optical fiber. The holey fiber includes a core region that is formed at a center of the holey fiber and a cladding region having a plurality of holes around the core region at regular intervals. The dispersion-compensating optical fiber is connected close to the holey fiber and that collectively compensates wavelength dispersion of the holey fiber at an operation wavelength in at least two wavelength bands out of O band, E band, S band, C band, and L band within a predetermined range depending on a transmission rate.

Abstract: The invention pertains to optical fiber transmission systems, and is particularly relevant to optical transport systems employing optical amplifiers. In particular the invention teaches an apparatus and method that allows cost effective co-directional operation of an optical amplifier to support full duplex traffic on a single fiber, and the design of an optical fiber transmission system based on this optical amplifier technology.

Abstract: An optical fiber transmission system including: a first transmission-line optical fiber to input first wavelength signal light output from a transmitter, and to change a waveform of the signal light; an optical coupler to combine the first wavelength signal light that has been propagated through the first transmission-line optical fiber with second wavelength pumping light; an optical limiter to input coupled light output from the optical coupler, saturating a gain as power of the coupled light increases using a nonlinear optical medium, thereby suppressing an optical noise component included in the coupled light, and to output signal light including the first wavelength optical component obtained from the nonlinear optical medium; and a second transmission-line optical fiber to input to a receiver after signal light output from the optical limiter is input and a waveform change by the first transmission-line optical fiber in the signal light is compensated for.

Abstract: An apparatus and method are applied to characterizing an dispersion-affecting element for use in controlling chromatic dispersion in an optical communications link. Information regarding the behavior of the dispersion-affecting element is recorded and stored in a medium that is provided for deployment with the dispersion-affecting element to enable improved management and active control of the dispersion-affecting element. The suitability of the dispersion-affecting element for operating under different conditions may also be characterized.

Abstract: In order to enhance dispersion control, the apparatus includes a dispersion controller; a quality index generator generating a quality index representing a quality of an optical signal output from the dispersion controller; and a searching unit searching for an amount of dispersion control applying to the dispersion controller which amount optimizes the quality index, wherein the searching unit includes a splitting-half searching unit roughly searching, in a splitting half method, a range in which dispersion is controllable by the dispersion controller for an amount of dispersion control such that the quality index generated by the quality index generator becomes preferable, and a sweep searching unit thoroughly searching, by sweeping, a limited range based on the amount of dispersion searched by the splitting-half searching unit for an amount of dispersion control that optimizes the quality index generated by the quality index generator.

Abstract: A wavelength division multiplexing optical fiber transmission line that reduces signal deterioration caused by dispersion even in a transmission system having a high-speed transmission rate, and is suited to a long-distance transmission. A dispersion management transmission line is connected between optical repeaters. The dispersion management transmission line has 3 to 6 pairs of fiber sections, of which each has a positive dispersion fiber and a negative dispersion fiber, connected in series. Dispersion compensation is made step by step over four (4) times for dispersion and a dispersive slope, which were accumulated by the front-stage positive dispersion fiber, by the next-stage negative dispersion fiber.

Abstract: A low-cost configuration of, and at the same time to control the variable dispersion compensator at a high speed in a variable dispersion compensator for compensating the wavelength dependent accumulated dispersion resulting from the wavelength dependency of the transmission fiber and fixed dispersion compensator in a long-distance high-speed WDM transmission system. In order to achieve the object mentioned above, the wavelength dependent representative characteristic of the transmission fibers 4-1 . . . n, and the wavelength dependent representative characteristic of the DCFs 13-1 . . . n are recorded and maintained in advance in the dispersion control circuit 5-1 . . .

Abstract: An optical fiber device converts an input optical pulse having a predetermined center wavelength into an optical pulse having a wavelength bandwidth broader than that of the input optical pulse. The optical fiber device includes a plurality of optical fibers connected in a cascaded manner each having negative wavelength dispersion at the center wavelength. The optical fibers have different relative refractive index differences between a core region and a cladding region from each other. The optical fibers are connected such that wavelength dispersions of adjacent optical fibers at the center wavelength are different from each other.

Abstract: The present invention provides systems and methods for chirp control of a dual arm Z-modulator to minimize dispersion in the fiber plant. The chirp control is based upon a real-time control loop based upon performance monitoring data between a transmitter and a receiver. Advantageously, the present invention enables improved performance in high-speed optical systems, and in some cases can eliminate or minimize the need for external dispersion compensation fiber (DCF).

Abstract: A scheme is described for mitigating the effects of polarization-mode dispersion (PMD) in a wave-division multiplex (WDM) optical communication system having one or more transmission links with one or more quasi-static waveguide sections coupled by one or more non-static coupling sections. A transmitter is coupled to the transmission link and is adapted to transmit optical signals through the transmission link with wavelength channel spacing of the optical signals greater than about the PMD correlation bandwidth of at least one of the one or more quasi-static waveguide sections, so that the PMD induced outage probability for the system is optimized.

Abstract: An apparatus and method are applied to characterizing an dispersion-affecting element for use in controlling chromatic dispersion in an optical communications link. Information regarding the behavior of the dispersion-affecting element is recorded and stored in a medium that is provided for deployment with the dispersion-affecting element to enable improved management and active control of the dispersion-affecting element. The suitability of the dispersion-affecting element for operating under different conditions may also be characterized.

Abstract: A dispersion compensation system includes a dispersion compensation module and a dispersion enhancement module. The dispersion compensation module receives optical input and provides optical output having a negative dispersion relative to the optical input. The dispersion enhancement module receives optical signals from a transport fiber and may increase positive dispersion in the optical signals by a configured amount such that the positive dispersion provided by the transport fiber and the dispersion enhancement module substantially equals the magnitude of the negative dispersion provided by the dispersion compensation module.