Abstract: A source of optical pulses, comprises an optical source operable to generate ultrashort optical pulses at a first wavelength; and an optical fiber amplifier comprising an optical fiber having a core containing a dopant to provide optical gain at the first wavelength and anomalous dispersion over a wavelength range including the first wavelength and a second wavelength. The optical fiber receives the ultrashort optical pulses, amplifies the ultrashort optical pulses, and alters the wavelength of the ultrashort optical pulses to at least the second wavelength by the soliton-self-frequency shifting effect. Microstructured and/or tapered fibers can be used to provide the required dispersion characteristics. Pulses can be generated in one of three spectral regimes—monocolor solitons, multicolor solitons and continuous broadband spectra by adjusting the energy of the optical pulses, and tunability can be achieved by varying the power of pump light provided to the amplifier.

Abstract: A glass fiber (22) has a core (24) provided with Raman laser effect particles (28) embedded in a glass matrix (30), with glass cladding (26) around the core. The refractive index of the glass matrix (30) is matched to that of the Raman laser effect particles (28) so as to avoid scattering. It is not necessary to have a single crystal of Raman laser material to create a laser effect in the glass fiber. A length of fiber in the order of meters or tens of meters can produce optical laser light. It is possible to have a single fiber (22) emit laser light at different frequencies due to Stokes and Anti-Stokes emissions. A simple laser device can therefore produce several colors of laser beams.

Abstract: The present invention relates to all optical choppers for shaping and reshaping. A chopper according to some embodiments of the invention may include a threshold device having an input terminal for receiving an optical input signal and an output terminal for emitting an optical output signal in response to a part of the input signal having intensity above a threshold level of the chopping device, wherein the output signal is narrower than the input signal. In other embodiments the device may include a first splitting device having at least first, second and third terminals, and at least one nonlinear element, wherein the second and third terminals form an optical loop including at least one nonlinear element displaced from the center of the optical loop, wherein the splitting device is arranged to receive an input signal for producing a first output signal that is narrower than the input signal. In further embodiments the optical loop includes at least one more attenuator.

Abstract: Some exemplary embodiments of one version of the present invention provide an optical switch including: a splitting device having first, second, third and fourth terminals; a nonlinear element; an attenuator; and an optical loop associated with the third and fourth terminals, the optical loop including the attenuator and the nonlinear element, the nonlinear element being displaced from a mid-point of the optical loop, wherein the splitting device is able to receive an input signal via one of the first and second terminals and an activating signal via one of the first and second terminals and to provide an output signal at one of the first and second terminals in response to the activating signal. In exemplary embodiments of alternative versions of the present inventions, the optical switch may include a threshold device. In some versions, the optical switch may be operated with a continuous wave or a pulse based activating signal.

Abstract: Embodiments of the invention include system for monitoring the effectiveness of pulse shaping in a nonlinear optical fiber (40). The spectral content of the pulse, after passing through the nonlinear fiber (40), provides an indication of how effectively the pulse was regenerated. A portion of the pulse exiting the nonlinear fiber is tapped off and its pulse energy is measured in at least one selected spectral region. The selected spectral region is one in which the pulse tends to gain energy when effective regeneration is taking place. The information concerning the effectiveness of pulse shaping in a nonlinear optical fiber is fed back to dynamically change the residual dispersion at the regenerator input. The spectral measurement leads to a control signal (48) to indicate a level of performance of the system, or to improve the performance of the system by adjusting an operational parameter.

Abstract: A wavelength converter has a phase modulated periodically modulated structure, where a nonlinear optical coefficient is periodically modulated at a fundamental period &Lgr;0 and the phase of the modulation varies nearly continuously, and the phase variation of the modulation unit structure is repeated at a period &Lgr;ph (>&Lgr;0). A conversion efficiency is made maximum when a phase mismatch amount &Dgr;&bgr; equals 2&pgr;/&Lgr;0±2&pgr;i/&Lgr;ph (i=0, 1, . . . , n, where n is a positive integer), 2&pgr;/&Lgr;0±2&pgr;(2i+1)/&Lgr;ph (i=0, 1, . . . , n), or 2&pgr;/&Lgr;0+2&pgr;i/&Lgr;f (i=m, m+1, . . . .

Abstract: The invention provides organic optical waveguide devices which employ perfluoropolymeric materials having low optical loss and low birefringence. An optical element has a substrate; a patterned, light transmissive perfluoropolymer core composition; and a light reflecting cladding composition on the pattern of the core. Writing of high-efficiency waveguide gratings is also disclosed.

Abstract: An optical memory having an input port for receiving an input optical signal to be stored in the optical memory is disclosed. A portion of the optical signal is coupled to a storage loop for storing optical signals by a coupler that transfers a portion of the input optical signal to the storage loop. An optical signal stored in the storage loop is output by coupling a portion of that optical signal to a first external optical waveguide. The storage loop includes a semiconductor optical amplifier for amplifying the signals stored in the storage loop to compensate for losses incurred by those signals in traversing the storage loop. A plurality of such optical memories can be combined to form a larger memory that includes a reconditioning circuit that resets the amplitude of the optical signals to a value that depends on the amplitude of the optical signals.

Abstract: An ultra-compact, room-temperature, continuous-wave infrared source that can rapidly tune over a very wide spectral range. The targeted spectral overages are 3 &mgr;m to 4 &mgr;m, 4 &mgr;m to 6 &mgr;m, 6 &mgr;m to 8 &mgr;m, and 8 &mgr;m to 12 &mgr;m. The spectral width of the infrared idler is expected to be ˜10 MHz. In particular, the invention is a monolithically integrated device which requires no external pump lasers or bulk optics for its operation. The invention uses difference-frequency-generation in a highly nonlinear optical semiconductor waveguide with which high power semiconductor lasers are integrated to internally provide the tunable pump and signal waves.

Abstract: A process shifts wavelengths of optical pulses. The process includes transmitting an incoming optical pulse through a nonlinear optical material, splitting the transmitted pulse into a plurality of mutually coherent optical pulses, and recombining the mutually coherent pulses with temporal delays. The recombined pulses produce a temporal interference pattern. The pattern has a peak whose wavelength is shifted with respect to the wavelength of the incoming optical pulse.

Abstract: An optical device includes, in a predetermined section of an optical fiber, a first functional part having a plurality of Faraday crystal columns that are parallel to each other and almost penetrating perpendicularly to an optical axis of an optical fiber through a core thereof, and a second functional part having a plurality of holes that are parallel to each other and almost penetrating perpendicularly to the optical axis of the optical fiber 1 through the core thereof. A longitudinal direction of the Faraday crystal columns and a longitudinal direction of the holes form an angle of 45 degrees along a plane perpendicular to the optical axis. Thus, the optical device can be realized only by processing the optical fiber.

Abstract: An optical AND logic gate includes a summing gate having first and second inputs for receiving first and second optical signals, and a threshold device. The gate produces an output corresponding to the AND product of the first and second optical signals. In another version the AND gate includes first and second inputs for receiving first and second optical signals, and an optical loop for producing an output corresponding to the AND product of the first and second optical signals. In an alternative versions a NAND gate is provided by applying an optical logic NOT on an AND gate.

Abstract: A wavelength converting element having improved wavelength converting efficiency and having a beam shape which facilitates coupling to a fiber or the like, is manufactured at low cost. After a waveguide is formed by carrying out proton exchange at a lower substrate in which inverted domains are formed, an upper substrate is laminated to the lower substrate so as to oppose the waveguide. Thereafter, a heat treatment is carried out and protons diffuse into the upper substrate and the lower substrate such that the waveguide is made to be a waveguide whose refractive index distribution is symmetrical, and simultaneously, the upper substrate and the lower substrate are joined by the heat treatment.

Abstract: An optical threshold device including an optical loop having first and second terminals aid including at least one non-linear optical element and at least one optical attenuator; and an optical coupler able to couple a first portion of an input signal to the first terminal and a second portion of the input signal to the second terminal, wherein the optical loop is able to produce a first return signal at the second terminal and a second return signal at the first terminal, and wherein the optical coupler is able to combine the first and second return signals into an output signal.

Abstract: A wavelength converter implements high speed, high efficiency, low noise wavelength conversion without performing high voltage poling of a crystal, and enables switching and modulation of converted light in response to an electric field. A KLTN crystal, includes a deposited-gold electrode within its incidence plane, and is connected to a DC power supply via a copper wire. The crystal material is composed of KTa1-xNbxO3 and/or K1-yLiyTa1-xNbxO3. A polarizer controls the polarization of the fundamental wave in the direction parallel to the electric field, and launches it into the electrode of the KLTN crystal. The KLTN crystal, rotating on an axis in the direction of the electric field, launches only part of the generated SHG light with the same polarization direction as that of the incident light into a photo multiplier tube through a polarizer.

Abstract: An optical switch includes at least one light-receiving core for receiving an optical signal, a plurality of light-emitting cores which are used selectively for emitting the optical signal, and a plurality of waveguides connecting the light-receiving core and the plurality of light-emitting cores. A nonlinear optical element which, when pumped, changes its refractive index by 2% or above relative to the surroundings to control a traveling direction of the optical signal is disposed near at least one of the plurality of waveguides.

Abstract: A photonic crystal structure includes a microcavity (point defect). The photonic crystal structure (or just the microcavity) is doped with materials that exhibit electro-magnetic induced transparency (EIT) so as to increase the non-linear properties of the photonic crystal.

Abstract: A microstructured optical waveguide that supports the propagation of an optical signal of a desired wavelength is described. The optical waveguide includes a core region formed from an optically nonlinear material having a &ggr; of at least about 2.5×10−19 m2/W at 1260 nm. The optical waveguide also includes a cladding region surrounding the core region, the cladding region including a bulk material and a lattice of columns located in the bulk material, the lattice of columns having a pitch, and each column having a cross-sectional area. The pitch of the lattice and the areas of the columns are selected such that the dispersion of the optical signal at the desired wavelength is within the range of about −70 ps/nm-km to about 70 ps/nm-km.

Abstract: A method and system for suppressing signal distortions in optical signals associated with nonlinearity in optical fibers includes propagating an optical signal through a transmission medium, the transmission medium comprising a sufficiently low dispersion such that a nonlinear distortion imparted on the propagating optical signal by the transmission medium is imprinted primarily on an optical field phase of the optical signal, and converting the propagated optical signal to an electrical signal such that the optical field phase information of the optical signal is not translated into the electrical domain.

Abstract: An optical component is an optical fiber grating element having a grating formed in the core region of an optical fiber, and a cladding region is made of silica glass. An optical material for the core region is ladder-type silicone resin, whose refractive index is set to a desired value by appropriately adjusting the mixing ratio between SiO and a functional group and the mixing ratio of a phenyl group to a methyl group. The optical component has a desired thermal expansion coefficient and desired temperature characteristics as a whole.

Abstract: An optical modulation apparatus includes an optical signal input section, an optical signal propagation path, an optical modulator that modulates the phase of optical signals in at least two of a plurality of optical paths, and a wavelength selective filter that selectively reflects and transmits. Optical signals input via the input section are divided into a plurality of optical paths at a branching point and phase modulated by the phase modulator, that divides the optical path into a plurality of optical paths. Light transmitted by the filter is output via the output section, while light reflected by the filter travels back along the optical path and is again phase modulated by the phase modulator combined at the branching point and output from the input section as an intensity modulated optical signal.

Abstract: An optical device is provided comprising a delay region having a photonic band structure, an optical input, an optical output, wherein the optical input is adapted to couple input optical signals into a predetermined mode in the delay region such that the optical signal is slowed and wherein the optical output includes a wavelength selective element. Input optical signals are coupled into a highly dispersive mode in the delay region in which the group velocity of the optical signal is reduced. The input signal, which has been delayed and dispersed, is recovered at the output of the device using the wavelength selective element.

Abstract: The present invention aims to simplify a mass production process of an optical waveguide device and to reduce cost as well as noise. The optical waveguide device includes an optical waveguide whose entrance end face and exit end face are substantially parallel to each other. A SHG device is mass-produced by optically polishing an optical material substrate with a large area and then cutting the substrate. This method can mass-produce the optical waveguide devices having a uniform device length. The angle between the exit end face of the optical waveguide and the direction of an optical axis of the optical waveguide at the exit end face is not 90°, thereby reducing return light from the exit end face.

Abstract: In one embodiment of the present invention, a method includes introducing an optical signal into a first arm and a second arm of an optical device; self-phase modulating the optical signal propagating in the first arm; and outputting a high intensity portion of the optical signal spatially separated from a low intensity portion of the optical signal. In such manner, optical signals input into the optical device may be restored via cleaning and shaping.

Abstract: An ultrafast all-optical nonlinear switch. The switch has as components a substrate and a material disposed on the substrate. In one embodiment, the material includes a plurality of single-walled carbon nanotubes and a polymer forming a composite. Preferably, the polymer is polyimide. In another embodiment, the material includes a plurality of single-walled carbon nanotubes incorporated into a silica. The nanotube loading in the material is less than about 0.1 wt %. The material is a substantially transparent, third-order nonlinear optical material. The switch has a switching speed of less than 1 picosecond for light with a wavelength of about 1.55 micrometers. Also disclosed is a process for preparing the ultrafast all-optical nonlinear switch.

Abstract: An optical device includes a waveguide bounded by a region containing a photonic band gap the properties of which determined the transfer characteristic of the waveguide. Such a device may serve as a component of, for example a wavelength division multiplexer, a monochromatic laser or a chemical sensor. It may serve as an optical bus for an electronic component such as a microprocessor. These devices are particularly suitable for incorporation in optical and opto-electronic integrated circuits as they permit the fabrication of waveguides having right-angle bends with a radius of the order of 2 &mgr;m.

Abstract: In the present invention, an optical device having a waveguide structure includes a photonic band structure region, the photonic band structure region comprising a first region having a first refractive index and an array of sub-regions having a second refractive index, the array of subregions being arranged in a Fibonacci spiral pattern. The present invention can also be applied to optical fibers. The Fibonacci spiral pattern and can be found in nature in the arrangement of the seeds of a sunflower and in pine kernels. The Fibonacci pattern is an optimal packing system for the sub-regions surrounding a central cavity region.

Abstract: An optical fiber suitable for generation of a supercontinuum spectrum when light pulses of femtosecond (10−15 sec.) duration are launched at a certain wavelength into the fiber. The fiber includes a number of sections of highly non-linear fiber (HNLF) wherein each section exhibits a different dispersion at the wavelength of the launched light pulses. The fiber sections are joined, for example, by fusion splicing the sections in series with one another so that the dispersions of the sections decrease from an input end to an output end of the fiber. In the disclosed embodiment, a low noise, coherent supercontinuum spanning more than one octave is generated at the output end of the fiber when pulses of light of 188 fs duration are launched into the fiber at a repetition rate of 33 MHz and with an energy of three nanojoules per pulse.

Abstract: A method and apparatus for modulating light with an array of nanocrystals. First photons are directed onto an array of nanocrystals and at least a portion of the first photons ate directed by the array of nanocrystals. In one embodiment, the array of nanocrystals emit second photons. A wavelength of the second photons is modulated responsive to a signal. In one embodiment, dopants are formed proximate to the array of nanocrystals and energy from the absorbed portion of the first photons is coupled to the dopants to cause the to emit third photons. An intensity of the third photons is modulated responsive to a signal.

Abstract: Disclosed is a nonlinear dispersion-shifted optical fiber, wherein a charomatic dispersion at a wavelength of 1550 nm is equal to a set value required for optical signal processing utilizing a nonlinear phenomenon, a dispersion slope at a wavelength of 1550 nm falls within a range of 0.001 to 0.1 ps/nm2/km, a margin of fluctuation of the charomatic dispersion in a longitudinal direction of the optical fiber at a wavelength of 1550 nm falls within a range of 0.01 to 3 ps/nm/km, and a nonlinear constant n2/Aeff at a wavelength of 1550 nm is not smaller than 15×10−10/W.

Abstract: A technique for electrically mounting a surface-normal optical device or material on a waveguide-type optical device while the characteristics of the mounted device are effectively used is disclosed. The waveguide-type optical device comprises a substrate on which optical waveguides or fibers are provided and a trench is formed; a pair of electrodes which is assigned to each optical waveguide or fiber and is formed from the surface of the substrate to wall surfaces of the trench; and a material or device which is filled or inserted into the trench, and which has an electro-optic effect, thermo-optic effect, light emitting function, light receiving function, or light modulating function. Another type of device comprises a thin and surface-normal active optical device driven by an applied voltage, which is substantially vertically inserted into the trench and is fixed in the trench; and a support member attached to the inserted device.

Abstract: A non-linear optical loop mirror for processing optical signals comprises an optical fiber, a bi-directional amplifier, and a coupler. The optical fiber has a signal input and a signal output. At least a portion of the optical fiber includes a dispersion compensating fiber. At least a portion of the optical fiber forms a loop. The dispersion compensating fiber has an absolute magnitude of dispersion of at least 20 ps/nm-km for at least a portion of wavelengths in the optical signals. The bi-directional amplifier is coupled to the optical fiber. The coupler is coupled to a first portion of the optical fiber and a second portion of the optical fiber to form a fiber loop.

Abstract: An optical-path-superposing-and-separating unit superposes optical paths of two inputted signal lights with each other, and then separate them. A non-linear waveguide is arranged in an area where the optical paths are superposed with each other. First and second optical waveguide are connected to the optical path superposing-and-separating unit. The second optical waveguide has a longer optical path than the first optical waveguide. A control light is introduced to the non-linear waveguide. An interference separator distributes the inputted two signal lights depending on a phase difference therebetween. Third and fourth optical waveguides connect the optical-path-superposing-and-separating unit to the interference separator.

Abstract: The invention relates to an optical device. The optical device comprises a waveguide core and a nanocomposite material optically coupled to the waveguide core. The nanocomposite material includes a plurality of quantum dots. The nanocomposite material has a nonlinear index of refraction &ggr; that is at least 10−9 cm2/W when irradiated with an activation light having a wavelength &lgr; between approximately 3×10−5 cm and 2×10−4 cm.

Abstract: A nonlinear optical loop mirror having a first optical coupler including first and second optical paths directionally coupled together, a loop optical path formed of a nonlinear optical medium for connecting the first and second optical paths, and a second optical coupler including a third optical path directionally coupled to the loop optical path. An optical signal whose waveform is to be measured is supplied into the nonlinear optical loop mirror from the first optical path. An optical trigger having a predetermined pulse width is supplied into the nonlinear optical loop mirror from the third optical path. Information on the waveform of the optical signal is obtained according to light output from the second optical path. The predetermined pulse width of the optical trigger is set according to the required measurement accuracy, so that the waveform of the optical signal can be faithfully observed with a high time resolution.

Abstract: A nonlinear optical chromophore having the formula D-&pgr;-A, wherein &pgr; is a &pgr; bridge including a thiophene ring having oxygen atoms bonded directly to the 3 and 4 positions of the thiophene ring, D is a donor, and A is an acceptor.

Abstract: A method of and apparatus for creating a second order non-linearity profile along a waveguide. The method comprises: thermally poling a waveguide structure to generate a second order non-linearity; placing a mask adjacent to the waveguide structure; and exposing the waveguide structure with UV light through the mask to selectively erase the second order non-linearity along the waveguide structure. The mask may be an amplitude mask or phase mask. In a preferred embodiment an amplitude mask is used in combination with an incoherent UV light source to produce selective erasure of a thermally poled second order non-linearity. Apparatus for carrying out this method and devices based on waveguide structure fabricated using the method are also described.

Abstract: A multi-channel light source generator has a pumping laser source for generating a pumping laser having a predetermined wavelength, a multi-channel light source generating device for generating multi-channel light sources using the pumping laser, a light separating device for separating the pumping laser and the multi-channel light sources, a demultiplexing device for separating the multi-channel light sources into a plurality of individual light sources, an intensity adjusting device for adjusting an intensity of the individual light sources, and a multiplexing device for combining the individual light sources outputted from the intensity adjusting device.

Abstract: An optical switch, in which focal position of beams is adjusted to provide a high switching efficiency and a high stability in action without increasing a light source output of a control light, comprising a condensing means for making a signal light and a control light convergent and incident upon a nonlinear optical thin-film and wherein irradiation of the control light causes a change of the nonlinear optical thin-film in refractive index to thereby change the signal light into a transmitted light or a reflected light to take out the same as an output signal.

Abstract: A broadband optical spectrum generating apparatus 20 includes an ultra-short pulse fiber laser 22 that generates pulsed light having a pulse width in a unit of picosecond to femtosecond, and a broadband optical spectrum-generating optical fiber 24 that is connected with the ultra-short pulse fiber laser 22 via a lens 26 and has a non-linear coefficient of not less than 10 [W−1m−1] at a wavelength of the pulsed light and a magnitude of chromatic dispersion of not greater than 2 [ps/km/nm]. The pulsed light emitted from the ultra-short pulse fiber laser 22 is converted into a relatively flat super continuum over a broad band of approximately 1200 nm to 2000 nm by chromatic dispersion in the course of transmission through the broadband optical spectrum-generating optical fiber 24.

Abstract: A multiple-wavelength ultrashort-pulse laser system includes a laser generator producing ultrashort pulses at a fixed wavelength, and at least one and preferably a plurality of wavelength-conversion channels. Preferably, a fiber laser system is used for generating single-wavelength, ultrashort pulses. An optical split switch matrix directs the pulses from the laser generator into at least one of the wavelength conversion channels. An optical combining switch matrix is disposed downstream of the wavelength-conversion channels and combines outputs from separate wavelength-conversion channels into a single output channel. Preferably, waveguides formed in a ferroelectric substrate by titanium indiffusion (TI) and/or proton exchange (PE) form the wavelength-conversion channels and the splitting and combining matrices. Use of the waveguide allows efficient optical parametric generation to occur in the wavelength-conversion channels at pulse energies achievable with a mode-locked laser source.

Abstract: A fluorescent structure comprising a plurality of quantum dots that radiate emission in response to optical pumping. These quantum dots are disposed in relation to a waveguide so as to be able to propagate this emission through the waveguide. Preferably, the fluorescent structure comprises a layer of quantum dots sandwiched between two layers, at least one layer being optically transmissive to the pump radiate and at least one of the layers being optically transmissive to emission from the quantum dots.

Abstract: A device including a chirped Bragg grating, said grating having (a) a reflection bandwidth having a full-width at half maximum that is greater than 6 nm, and (b) a reflection delay ripple amplitude of less than ±50 ps.

Abstract: A waveguide device is provided comprising an optical waveguide core and a cladding optically coupled to the optical waveguide core. The cladding comprises an optically functional region defining a refractive index that is configured to vary in response to a control signal applied to the optically functional region. The refractive index of the optically functional region is lower than the refractive index of the optical waveguide core. In accordance with one embodiment of the present invention, the optically functional region may be characterized as a Kerr Effect medium. In accordance with 37 CFR 1.72(b), the purpose of this abstract is to enable the United States Patent and Trademark Office and the public generally to determine quickly from a cursory inspection the nature and gist of the technical disclosure. The abstract will not be used for interpreting the scope of the claims.

Abstract: An optical fiber includes a core for guiding light of a specified range of wavelengths therethrough, each wavelength in the specified range of wavelengths traveling through the core at a particular group velocity and the light potentially producing a nonlinear optical effect. The optical fiber also includes a cladding formed around the core for substantially containing the light within the core. The optical fiber further includes a predetermined amount of at least one dopant uniformly dispersed throughout the core such that no two distinct wavelengths in the specified range of wavelengths travel through the core at the same, particular group velocity, thereby causing the nonlinear optical effect to be suppressed.

Abstract: A non-linear optical loop mirror for processing optical signals comprises an optical fiber, a bi-directional amplifier, and a coupler. The optical fiber has a signal input and a signal output. At least a portion of the optical fiber includes a dispersion compensating fiber. At least a portion of the optical fiber forms a loop. The dispersion compensating fiber has an absolute magnitude of dispersion of at least 20 ps/nm-km for at least a portion of wavelengths in the optical signals. The bi-directional amplifier is coupled to the optical fiber. The coupler is coupled to a first portion of the optical fiber and a second portion of the optical fiber to form a fiber loop.

Abstract: An optical system includes a delay region having a photonic band structure, a modulated optical signal source, an optical input, and an optical output. The optical input couples modulated input optical signals into a predetermined mode in the delay region such that group velocity of the optical signal is reduced. The optical output includes a wavelength selective element. Input optical signals are coupled into a highly dispersive mode in the delay region in which the group velocity of the optical signal is reduced. The input signal, which has been delayed and dispersed, is recovered at the output of the device using the wavelength selective element.

Abstract: A first electrode and a second electrode are provided in separation on a main surface of a substrate made of a ferroelectric single crystal. A first voltage is applied between the first electrode and the second electrode, for example, on condition that the first electrode is positive and the second electrode is negative, to generate and grow a first polarization-inverted portion toward the second electrode from the first electrode. Then, the distance between the first electrode and the second electrode is changed, and a second voltage is applied between the first electrode and the second electrode on the same condition, to generate and grow a second polarization-inverted portion, in a different area from that of the polarization-inverted portion, toward the second electrode from the first electrode.

Abstract: In the present invention an optical pulse regenerating transmission line element includes a section of disbursement managed optical fibre transmission line in optical communication with an unbalanced optical interferometer. The transmission line element may be particularly suitable for use with RZ optical pulses, and in particular optical solitons. The dispersion managed optical fibre transmission line includes a first section of optical fibre having a negative dispersion coefficient, connected to a second section of optical fibre having a positive dispersion coefficient. This first section of fibre may be dispersion compensating fibre and the second section of fibre may be standard monomode fibre. It is preferred that the first and second sections of optical fibre are arranged to form a section of dispersion managed optical fibre transmission line having a symmetric dispersion map.

Abstract: An optical fiber transmission line including first, second and third optical fibers connected together so that light travels through the transmission line from the first optical fiber, then through the second optical fiber and then through the third optical fiber. The first, second and third optical fibers have first, second and third characteristic values, respectively. The second characteristic value is larger than the first characteristic value and the third characteristic value. The characteristic value of a respective optical fiber being a nonlinear refractive index of the optical fiber divided by an effective cross section of the optical fiber. Pump light is supplied to the transmission line so that Raman amplification occurs in the transmission line as an optical signal travels through the transmission line.