Abstract: An optical fiber delivery system for delivering ultrashort optical pulses that can efficiently transmit high peak power, ultrashort optical pulses from an optical pulse source to a desired position in an optical apparatus is provided. An optical system including such an optical fiber delivery system is also provided. The optical fiber delivery system includes light waveguide means 20 for receiving high-peak power, ultrashort optical pulses and transmitting the optical pulses, negative group-velocity dispersion generation means 30 for providing negative group-velocity dispersion to the optical pulses transmitted through the light waveguide means 20, and an optical fiber 40 that transmits the optical pulses transmitted through the negative group-velocity dispersion generation means 30 along a desired distance. The incident ultrashort optical pulses that have been injected into the light waveguide means 20 are converted into down-chirped pulses.

Abstract: A polarization state adjusting optical element is formed by a ½ wavelength plate and a ¼ wavelength plate and its polarization direction and elliptic degree are adjusted. By adjusting the polarization state adjusting optical element in advance, even if the output of a pump light source is changed, the polarization characteristic (polarization direction and elliptic degree) of the output light of an FDFA amplifier will not not change or the change is sufficiently small. In this state, a polarization state adjusting optical element adjusts the polarization state of the laser beam coming into a wavelength conversion optical system so that the wavelength conversion optical system has the maximum conversion efficiency. Thus, it is possible to provide an FDFA having a small change of the polarization state of the output light even if the pump light intensity is changed.

Abstract: Grooves (22, 23) for containing an optical fiber and five recesses (24) for containing the optical components for an optical fiber amplifier are provided in the surface of a substrate (21). An optical fiber fitted in a groove (23a) for containing the optical fiber and introduced to the substrate (21) is passed through a groove (22a) for containing the optical fiber and fitted in a groove (22) for containing the optical fiber, thence passed through a groove (22b) for containing the optical fiber and introduced to the outside of the substrate (21). In the recess (24) for containing the optical component for an optical fiber amplifier, an optical component such as a photocoupler is fitted and coupled with the optical fiber. Light such as pumping light is passed through an optical fiber contained in the groove (23) for containing the optical fiber and introduced to an optical component such as a photocoupler.

Abstract: The present invention provides methods, systems, and apparatus of improved fiber-based optical parametric oscillators (FOPOs). These oscillators can be used in the creation of short pulsed laser radiation, which are useful in numerous applications, such as characterization of materials and molecules. A relationship between fiber length and performance is realized, where shorter lengths counterintuitively provide greater power and width of output bands. This relationship is used to develop improved FOPOs. For example, fibers of 10 cm or less may be used to obtain superior performance in terms of wavelength tunability (e.g. bandwidth of 200 nm and greater) and output power (e.g. pulse power of 1 nJ). Other realized relationships between length and wavelength position of output bands are also used to select the wavelength range output from the FOPO. The diameter of the fiber may be selected to provide positioning (e.g. a centering) of the range of attainable output wavelengths.

Abstract: A chirped pulse amplification (CPA) system comprises an optical pulse stretcher and an optical pulse compressor that are mismatched in that the optical pulse compressor includes a bulk optical grating while the optical pulse stretcher does not. High order dispersion compensation is provided by an optical phase mask disposed within the optical pulse compressor.

Abstract: An optical amplifier comprises an optical fibre, a pump laser for optically pumping the optical fibre to amplify an optical signal, a TEC 1 for cooling the pump laser on receipt of a cooling current, a temperature sensor 2 for monitoring the temperature of the amplifier housing; and a control circuit 3 for controlling the cooling current in dependence on a sensing output from the temperature sensor 2, so as to maintain the temperature of the pump laser at a temperature set point. The control circuit 3 is configured (i) to maintain the temperature of the pump laser at a first temperature set point within a predetermined temperature range of the amplifier, and (ii) to maintain the temperature of the pump laser at a second temperature set point, higher than the first temperature set point, when the sensing output from the temperature sensor 2 exceeds a threshold value.

Abstract: To induce a targeted non-linear optical effect by a high-peak-power light by using a light pulse from a semiconductor laser without using a light pulse from a large, high-average-power solid laser such as titanium sapphire laser. A semiconductor laser pulse beam with a wavelength of 1550 nm (for example, repeatability of 1 MHz) from a semiconductor laser (laser diode: LD) is efficiently amplified in two stages, front-end and main EDFAs. An optical filter removes a spontaneous emission light component that is noise. An optical filter picks up, from the amplified pulse beam, second harmonic light pulse produced by the non-linearity of an optical device (frequency polarization inversion Mg-added LiNbO3:PPMgLN) to produce a super-continuum light in a 800 nm wavelength region from a photonic crystal fiber (PCF).

Abstract: A short-pulse fiber amplifier system (10) is designed so that nonlinear phase shifts and third-order dispersion are purposely introduced that compensate each other. In particular, the nonlinear phase shift accumulated in the amplifier is compensated by the third-order dispersion of the combination of a fiber stretcher (12) and a grating compressor (16). In the presence of third-order dispersion, an optimal nonlinear phase shift reduces the pulse duration, and enhances the peak power and pulse contrast compared to the pulse produced in linear propagation.

Abstract: An optical amplifier is disclosed having a relatively high gain and low noise figure across the broadband wavelength range. In an exemplary embodiment, the optical amplifier comprises an optical fiber including a core doped with a fluorescent material, the optical amplifier having an associated first noise figure. The optical amplifier also comprises a semiconductor optical amplifier portion being optically coupled to the optical fiber, the semiconductor optical amplifier portion having an associated second noise figure, wherein the first noise figure is less than the second noise figure.

Abstract: Apparatus and method for spectral-beam combining light from a plurality of high-power fiber lasers that, in some embodiments, use two substantially identical diffraction gratings in a parallel, mutually compensating configuration to combine a plurality of separate parallel input beams each having a slightly different successively higher wavelength into a single output beam of high quality. In other embodiments, a single diffraction grating is used to combine a plurality of different wavelengths, wherein the input laser beams are obtained from very narrow linewidth sources to reduce chromatic dispersion. In some embodiments, diagnostics and adjustments of wavelengths and/or positions and angles are made dynamically in real time to maintain the combination of the plurality input beams into a single high-quality output beam.

Abstract: The present invention relates to an optical amplification module having a construction which effectively suppresses photodarkening, and to a laser light source including the same. The laser light source comprises a light source for outputting light to be amplified, and an optical amplification module. The optical amplification module comprises two types of optical amplification media having different rare earth element concentrations, and a pumping light source. The low concentration medium and the high concentration medium are disposed in the propagation direction of pumping light such that the population inversion of the low concentration medium is higher than that of the high concentration medium.

Abstract: The present invention relates in general to coupling of light from one or more input waveguides to an output waveguide or output section of a waveguide having other physical dimensions and/or optical properties than the input waveguide or waveguides. The invention relates to an optical component in the form of a photonic crystal fiber for coupling light from one component/system with a given numerical aperture to another component/system with another numerical aperture. The invention further relates to methods of producing the optical component, and articles comprising the optical component, and to the use of the optical component. The invention further relates to an optical component comprising a bundle of input fibers that are tapered and fused together to form an input coupler e.g. for coupling light from several light sources into a single waveguide. The invention still further relates to the control of the spatial extension of a guided mode (e.g.

Abstract: An optical fiber and an optical fiber device, which can suppress generation of the stimulated Brillouin scattering while maintaining large nonlinearity. The fiber includes a central core which is made of SiO2 as a main component and contains Al2O3 at concentration of 15 wt % or more. The fiber is allowed to propagate only a fundamental mode and has an absolute value of chromatic dispersion of 5 ps/nm/km or less at a predetermined wavelength. The device includes the fiber having the above composition. The fiber guides first light and second light having different wavelengths to propagate therethrough such that the first light and the second light interact with each other by a nonlinear optical phenomenon during the propagation, thus causing the fiber to output the first light or the second light modulated by the nonlinear optical phenomenon or third light newly produced by the nonlinear optical phenomenon and having a different wavelength.

Abstract: A method for generating a linear single-polarization output beam comprises providing an optically active linearly birefringent and linearly dichroic fiber for propagating light and having a single polarization wavelength range and a gain bandwidth; optically pumping the optically active linearly birefringent and linearly dichroic fiber for obtaining fluorescence within the gain bandwidth; and aligning the single-polarization wavelength range to overlap a desired spectral region of the gain profile.

Abstract: A fiber amplifier includes at least one coreless end used for the input or extraction of optical energy. The coreless end has a transverse cross section which differs from the transverse cross section of the core at fiber locations remote from the end, so that the diameter of the input or extracted optical beam at the coreless end can be larger than the diameter of the fiber core, to increase an optical damage threshold of the fiber amplifier.

Abstract: A tellurite glass composition doped with a first lanthanide, preferably Tm, and codoped with another lanthanide oxide, e.g. Ho, is provided. The glass includes 4-12 mole % of alkalihalide XY, X being selected from the group of Li, Na, K, Rb, Cs and Fr and Y being selected from the group of F, Cl, Br and I. A preferred glass contains about 10 mole % of the alkalihalide CsCl. The addition of alkalihalide XY results in an enhanced energy transfer from the first to the second lanthanide ion, whereby the lower energy level of the first lanthanide ion is depopulated. The ratio between upper and lower energy level lifetimes for the first lanthanide ion can be reduced to a value below one, enabling efficient amplifier fibers.

Abstract: A transmission fibre with optical amplification, comprising a core and a cladding. The core material is doped with a first dopant of a material having a higher index of refraction than the material of the cladding and with a second dopant of a material that converts pump energy in the form of light having a first wavelength into light having a second wavelength. The concentration of the second dopant within the core increases in radial direction in proportion to the distance to the centre of the core. The core material is preferably doped with a third dopant for compensating the variation in the refractive index caused by the second dopant. The cladding may comprise a cladding layer surrounding the core provided with a fourth and a fifth dopant for signal amplification and refractive index compensation, respectively, in the cladding layer. The dopants have been selected to enable amplification, using the Raman effect or stimulated emission.

Abstract: The specification describes an optical fiber device wherein a LOM is converted to an HOM prior to entering the gain section. The gain section is a few mode fiber that supports the HOM. The output from the gain section, i.e. the HOM, may be utilized as is, or converted back to the LOM. With suitable design of the few mode fiber in the gain section of the device, the effective area, Aeff, may be greater than 1600 ?m2. The large mode separation in the gain section reduces mode coupling, allowing greater design freedom and reducing the bend sensitivity of the optical fiber.

Abstract: By optimizing the refractive index profile, the absorption coefficient of a rare earth element doped optical fiber can be enlarged and nonlinear effect can be suppressed. Thus, according to the present invention, the optical fiber, which is suitable for wide band optical amplification, can be realized. Moreover, in the present invention, the optical fiber of W-shape profile comprising a core, the first cladding having a refractive index smaller than that of said core surrounding said core, and the second cladding having a refractive index smaller than that of said core and larger than that of said first cladding surrounding said first cladding is prepared and are suitable for the wide band optical amplification.

Abstract: A fiber amplifier for amplifying an optical signal, comprising a pump energy source capable of emitting energy at a pump wavelength: optical apparatus for transmitting the optical signal, the optical apparatus having a plurality of discrete portions, each discrete portion comprising a length of optical fiber and first and second components disposed at first and second respective locations and configured to substantially prevent energy having an intermediate wavelength in the discrete portion from entering other discrete portions of the optical apparatus; and a plurality of waveguides, each waveguide coupled to the pump energy source and to one of the plurality of discrete portions, each waveguide for providing energy at the pump wavelength from the pump energy source to its corresponding discrete portion, thereby increasing an intensity of light at the discrete portion's intermediate wavelength.

Abstract: The invention describes techniques for the control of the spatial as well as spectral beam quality of multi-mode fiber amplification of high peak power pulses as well as using such a configuration to replace the present diode-pumped, Neodynium based sources. Perfect spatial beam-quality can be ensured by exciting the fundamental mode in the multi-mode fibers with appropriate mode-matching optics and techniques. The loss of spatial beam-quality in the multi-mode fibers along the fiber length can be minimized by using multi-mode fibers with large cladding diameters. Near diffraction-limited coherent multi-mode amplifiers can be conveniently cladding pumped, allowing for the generation of high average power. Moreover, the polarization state in the multi-mode fiber amplifiers can be preserved by implementing multi-mode fibers with stress producing regions or elliptical fiber cores These lasers find application as a general replacement of Nd: based lasers, especially Nd:YAG lasers.

Abstract: There is provided a method of, and apparatus for, regulating radiation component (wavelength channel) power in a wavelength division multiplexed (WDM) optical communications system (10). The system (10) comprises a plurality of nodes (20) interconnected through optical waveguides (30, 40) (optical fibers). The method is characterised by: passing one or more tokens (300) around the system from node to node; adjusting nodal settings (150, 170), such as optical attenuation, applied at each node to regulate the power of WDM radiation components at the node in response to receiving one or more tokens; and repeating the method until WDM radiation component power within the system is substantially regulated.

Abstract: A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Abstract: An optical beam combiner and a related method for its operation, in which multiple coherent input beams are directed onto a diffractive optical element (DOE) along directions corresponding to diffraction orders of the DOE, such that the DOE generates a single output beam in a direction corresponding to a desired diffraction order, and suppresses outputs in directions corresponding to unwanted diffraction orders. The phases of the input beams are actively controlled to ensure and maintain the condition that only a single diffraction mode is present in the output of the DOE.

Abstract: The present invention relates to an optical amplification fiber and others capable of effectively reducing nonlinear interaction between signal channels even in transmission of multiplexed signal light containing multiple signal channels arranged in high density and also effectively reducing bending loss. An optical amplification module has an optical isolator, a WDM coupler, an Er-doped optical fiber (EDF) as an optical amplification fiber, a WDM coupler, and an optical isolator, which are arranged in order on a signal light propagation path from an input connector to an output connector, and further has a pumping light source connected to the WDM coupler and a pumping light source connected to the other WDM coupler. The EDF, at the wavelength of 1607 nm, has a mode field diameter (MFD) of 10 ?m or more to the fundamental mode and a MAC number (=MFD/cutoff wavelength) of 6.8 or less to the fundamental mode.

Abstract: An optical amplifier module is provided that contains at least one optical amplifier. The module includes an internal housing having an outer dimension substantially equal to an outer dimension of an internal fiber splice housing of an undersea optical fiber factory cable joint. The internal housing includes a pair of opposing end faces each having a retaining element for retaining the internal housing within an outer housing of the undersea optical fiber cable joint. The internal housing also includes a sidewall interconnecting the opposing end faces, which extends between the opposing end faces in a longitudinal direction. The sidewall includes a receptacle portion having a plurality of thru-holes each being sized to receive a passive optical component employed in an optical amplifier. The module also includes at least one circuit board on which reside electronics associated with the optical amplifier.

Abstract: A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Abstract: In each of a plurality of submarine observation apparatus (1 to n), a branching unit (63) branches fixed-wavelength light (?1) from an incoming wavelength-multiplexed light signal. An observation signal modulating unit (64) modulates the intensity of the branched fixed-wavelength light (?1) with observation information multiplexed by an observation signal multiplex unit (61). A combining unit (65) combines light signals (?2) to (?n) passing through the branching unit (63) and the fixed-wavelength light (?1a) modulated by the observation signal modulating unit (64) into a composite light signal, and outputs it to an optical fiber (12a). Therefore, in each of the plurality of submarine observation apparatus (1 to n), there is no necessity for providing a wavelength-division-multiplexing-transmission optical transmitter which requires high wavelength stability.

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 amplifier includes a detecting section configured to detect a part of an input optical signal from a first node on an input side optical fiber; and a rare earth element doped optical fiber amplifier configured to amplify a remaining part of the input optical signal supplied from the input side optical fiber by using an excitation optical signal supplied from a second node and to output the amplified optical signal as an output optical signal to an output side optical fiber. A control unit controls the excitation optical signal based on the detected part of the input optical signal by the detecting section without real time control based on the output optical signal.

Abstract: Multi-wavelength light is inputted to an erbium-doped fiber as an optical amplification medium. Pump light is supplied to this erbium-doped fiber. When a transition from a state signal light on the short wavelength area in the multi-wavelength is input in the erbium-doped fiber to a state the signal light is not input, the output power of signal light on the long wavelength area in the multi-wavelength light can vary. The wavelength of pump light is selected in such a way that the output power of the signal light on the long wavelength area can not be negative when the power varies.

Abstract: A method of adjusting Raman gain in an optical amplifier assembly (1a). The method comprises inputting a plurality (N) of optical signals (OS) on different wavelength channels to a backward-pumped Raman active medium (4a) pumped by means of a Raman pump source (5). The proposed method is characterized in that a slope with respect to time in a quantity representative of a respective amplified optical signal (OS?) on at least one existing/surviving channel is determined in case of channel add/drop, and in that the Raman pump source (5) is tuned depending on said change. In this way, fast and reliable Raman pump tuning can be achieved even in an optical amplifier assembly (1a) and an optical transmission system, respectively, which suffer from channel adds/drops.

Abstract: A method and apparatus is described that use an index-of-refraction profile having a significant central dip in refractive index (or another tailored index profile) within the core of a gain fiber or a gain waveguide on a substrate. The benefits of this central dip (more power with a given mode structure) are apparent when an input beam is akin to that of a Gaussian mode. In some embodiments, the invention provides a fiber or a substrate waveguide having an index profile with a central dip, but wherein the device has no doping. Some embodiments use a central dip surrounded by a higher-index ring in the index of refraction of the core of the fiber, while other embodiments use a trench between an intermediate-index central core portion and the ring, or use a plurality of rings and/or trenches. Some embodiments use an absorber in at least one core ring.

Abstract: A device for generating a plurality of laser pulses from a recirculating single laser pulse in an optical delay line that is capable of partially transmitting the trapped pulse out of the delay line. The energy of the partially reflected trapped pulse is restored before beginning another round trip in the delay line. The time structure of an output pulse train thus generated by the device comprises a sequence of macro pulses, each comprising a plurality of micro pulses.

Abstract: An optimized Yb: doped fiber mode-locked oscillator and fiber amplifier system for seeding Nd: or Yb: doped regenerative amplifiers. The pulses are generated in the Yb: or Nd: doped fiber mode-locked oscillator, and may undergo spectral narrowing or broadening, wavelength converting, temporal pulse compression or stretching, pulse attenuation and/or lowering the repetition rate of the pulse train. The conditioned pulses are subsequently coupled into an Yb: or Nd: fiber amplifier. The amplified pulses are stretched before amplification in the regenerative amplifier that is based on an Nd: or Yb: doped solid-state laser material, and then recompressed for output.

Abstract: A method and apparatus use a photonic-crystal fiber having a very large core while maintaining a single transverse mode. In some fiber lasers and amplifiers having large cores problems exist related to energy being generated at multiple-modes (i.e., polygamy), and of mode hopping (i.e., promiscuity) due to limited control of energy levels and fluctuations. The problems of multiple-modes and mode hopping result from the use of large-diameter waveguides, and are addressed by the invention. This is especially true in lasers using large amounts of energy (i.e., lasers in the one-megawatt or more range). By using multiple small waveguides in parallel, large amounts of energy can be passed through a laser, but with better control such that the aforementioned problems can be reduced. An additional advantage is that the polarization of the light can be maintained better than by using a single fiber core.

Abstract: The specification describes an optical fiber device wherein a LOM is converted to an HOM prior to entering the gain section. The gain section is a few mode fiber that supports the HOM. The output from the gain section, i.e. the HOM, may be utilized as is, or converted back to the LOM. With suitable design of the few mode fiber in the gain section of the device, the effective area, Aeff, may be greater than 1600 ?m2. The large mode separation in the gain section reduces mode coupling, allowing greater design freedom and reducing the bend sensitivity of the optical fiber.

Abstract: The present invention relates to an optical fiber amplifying module equipped with a structure for stably attaining a high gain even when amplifying light having a low duty cycle. The optical fiber amplifying module comprises at least three amplification optical fibers successively arranged from an input connector to an output collimator. A bandpass filter is arranged between the first- and second-stage amplification optical fibers. Control means having a structure constituted by optically passive components alone or a feedback structure functions so as to render an upper limit to a gain for input light in the first-stage amplification optical fiber, thereby preventing the deterioration in performances such as destruction of the bandpass filter from occurring in optical components positioned on the upstream side of the final-stage amplification optical fiber.

Abstract: System for converting relatively long pulses from rep-rate variable ultrafast optical sources to shorter, high-energy pulses suitable for sources in high-energy ultrafast lasers. Fibers with positive group velocity dispersion (GVD) and self phase modulation are advantageously employed with the optical sources. These systems take advantage of the need for higher pulse energies at lower repetition rates so that such sources can be cost effective.

Abstract: A fiber amplifier is configured such that its spontaneous emissions are filtered out at the instant of creation. The fiber optic amplifier combines the gain medium of the fiber optical amplifier with a continuous filter to filter out the spontaneous emissions to prevent spontaneously emitted photons from stealing gain from signal photons. The photonic crystal fiber has a central core doped with a gain medium such as erbium, ytterbium or thulium ions. The central core of the photonic crystal fiber is surrounded by a cladding region having an array of holes or air voids that may be filled with materials with refractive index different from that of the central core. The array of holes are configured to restrict the wavelength range within which light can propagate inside the central core thereby providing continuous filtering functionality. The fiber amplifier has a pump operative to generate pump energy that is coupled to the photonic crystal fiber simultaneously with the signal.

Abstract: A controller monitors output level variation rate of excitation light outputted by a light source in accordance with a drive current of the light source and provided to a rare-earth doped amplifying medium so that a signal light is amplified as the signal light travels through the amplifying medium. In an embodiment, the controller decreases the drive current when the monitored output level variation rate is larger than a threshold value, to thereby reduce power level of the outputted excitation light and thereby delay progress of degradation of the light source indicated by the monitored output level variation rate being larger than the threshold value.

Abstract: A polarization insensitive semiconductor optical amplifier (SOA) is provided. The SOA includes an active waveguide, a passive waveguide, and a taper coupler for coupling optical energy from the passive waveguide into the active waveguide, wherein the taper coupler has width W varying relative to position along a main axis z of propagation of the SOA in proportion to the minimum value of 1/CTE 01(z) 1/CTM 01(z), where CTE 01(z) represents the coefficient of energy coupling between a fundamental mode and a first order mode for the transverse electric polarization as a function of the position z, and CTM 01(z) represents the coefficient of energy coupling between a fundamental mode and a first order mode for the transverse magnetic polarization as a function of the position z.

Abstract: A fiber gain medium assembly is provided. The fiber gain medium assembly includes a fiber gain medium, which in turn, includes a longitudinally extending inner core. The fiber gain medium also includes a cladding layer and a photo-emitting conductive polymer, both of which surround the inner core and extend longitudinally therealong. In this regard, the photo-emitting conductive polymer can surround the cladding layer to thereby surround the inner core. Alternatively, the cladding layer can comprise the photo-emitting conductive polymer. The fiber gain medium assembly can also include an electrical system electrically coupled to the photo-emitting conductive polymer. The electrical system is capable of providing an electric field to thereby excite the photo-emitting conductive polymer to emit photons capable of propagating into the inner core and producing gain for the signals propagating through the inner core.

Abstract: The present invention relates to a fiber having a core of crystal fiber doped with chromium and a glass cladding. The fiber has a gain bandwidth of more than 300 nm including 1.3 mm to 1.6 mm in optical communication, and can be used as light source, optical amplifier and tunable laser when being applied for optical fiber communication. The present invention also relates to a method of making the fiber. First, a chromium doped crystal fiber is grown by laser-heated pedestal growth (LHPG). Then, the crystal fiber is cladded with a glass cladding by codrawing laser-heated pedestal growth (CDLHPG). Because it is a high temperature manufacture process, the cladding manufactured by this method is denser than that by evaporation technique, and can endure relative high damage threshold power for the pumping light.

Abstract: An optical amplifier includes an optical fiber having a core doped with transition metal ions, and at least one glass cladding enclosing the core. By using the fiber, the optical amplifier of the invention has a gain bandwidth of more than 300 nm including 1300-1600 nm band in low-loss optical communication.

Abstract: Method of synthesis of photonic band gap (PBG) materials. The synthesis and characterization of high quality, very large scale, face centered cubic photonic band gap (PBG) materials consisting of pure silicon, exhibiting a complete three dimensional PBG centered on a wavelength of 1.5 ?m. This is obtained by chemical vapor deposition and anchoring of disilane into a self-assembling silica opal template, wetting of a thick silicon layer on the interior surfaces of the template, and subsequent removal of the template. This achievement realizes a long standing goal in photonic materials and opens a new door for complete control of radiative emission from atoms and molecules, light localization and the integration of micron scale photonic devices into a three-dimensional all-optical micro-chip.

Abstract: An optical communication line of a communication system has a first processing station and an amplifying station. The line has a first optical connection having at least partially compensated accumulated dispersion and is placed between the first processing station and the amplifying station. A second optical connection having at least partially compensated accumulated dispersion is connected to the output of the amplifying station. Portions of optical fiber leaving the processing station and the amplifying station are associated to respective first order chromatic dispersions which are of opposite signs and have absolute values lower than or equal to 13 ps2/Km.

Abstract: A light source assembly (10) for a precision apparatus (11) includes a broadband light generator (12), an amplifier (14), and an optical filter (16). The light generator (12) generates a generator beam (22) that is directed at the amplifier (14). The amplifier (14) provides an amplified beam (24) by amplifying the generator beam (22). The optical filter (16) filters both the generator beam (22) and the amplified beam (24) so that an output beam (20) has a specific spectral width and a specific center wavelength, and so that the power available from the amplifier is concentrated within the desired spectrum. With this design, the light source assembly (10) can provide an output beam (20) having a spectrum determined by the filter and power which is not strongly dependent on the spectrum. For example, the output can have a specific, relatively narrow spectral width and a specific center wavelength, with sufficient power for use in precision measurement systems (11).

Abstract: An optical amplifier is described that comprises at least two sections of amplifying optical fibre and pumping means for optically pumping the amplifying optical fibre. Optical fibre support means, for example a channel or channels in a substrate, are also provided to hold the two or more sections of amplifying optical fibre substantially straight during use. The optical fibre support means also includes a means for coupling light between the at least two sections of amplifying optical fibre. The at least one amplifying optical fibre may comprise an Erbium doped core to provide an erbium doped fibre amplifier (EDFA).

Abstract: In an optical amplifier of the present invention, an input light is supplied to one end of an optical fiber connected to an output port, and the power of a light In an opposite direction which is input to the output port from the one end of the optical fiber, is measured, thereby obtaining a stimulated Brillouin scattering (SBS) occurrence threshold in the optical fiber based on the measurement result. Then, using the SBS occurrence threshold, a relation been the input light power and an occurrence amount of the self phase modulation (SPM) or the like in the optical fiber is obtained to be reflected on a control of the optical amplifier, so that an occurrence of the SPM or the like in the optical fiber is suppressed.