Abstract: A label removing tool has a blade located externally from the structural body. a blade moving means to angularly change, in relation to a rotational axis, the position of a blade holding block. The blade is dependent of the motion of the block by way of being attached to the block. The blade moves in both an angular displacement and a lateral shift from being off the rotational axis.

Abstract: The invention provides a multi-clad fiber, with three claddings or more, where at least one intermediate cladding is inserted between an inner core and an outer core of the multi-clad fiber, for enlarging the cross-section of the fiber core or for increasing the dopant density in the core. The invention also provides an intermediate cladding having a multi-layer structure to better confine the pump power in a suitable pumping region of the fiber.

Abstract: An optical fiber comprises a singlemode core, and an inner cladding disposed around said core, an intermediate cladding disposed around said inner cladding and an outer cladding disposed around said intermediate cladding thereby forming a triple-clad geometry. The core is doped with rare-earth elements and represents the waveguide section of higher refractive index through which the signal is transmitted and amplified. A fiber coating is provided around said outer cladding. The core has a higher refractive index than said inner cladding, said inner cladding having a higher refractive index than said intermediate cladding, and said intermediate cladding having a higher refractive index than said outer cladding. The inner cladding has a fairly high refractive index to limit the numerical aperture (NA) of said core.

Abstract: The invention provides a multi-clad fiber, with three claddings or more, where at least one intermediate cladding is inserted between an inner core and an outer core of the multi-clad fiber, for enlarging the cross-section of the fiber core or for increasing the dopant density in the core. The invention also provides an intermediate cladding having a multi-layer structure to better confine the pump power in a suitable pumping region of the fiber.

Abstract: A system and method for transmitting an optical signal through a downstream link of a Wavelength Division Multiplex (WDM) optical communications network, comprising a detector/filter for monitoring wavelength channels at an upstream link. An input source/filter transmits the optical signal in the wavelength channels through the downstream link. A controller receives data to be transmitted as an optical signal. The controller is connected to the detector/filter for detecting unused wavelength channels as a function of the monitoring from the detector/filter, for selecting one of the unused wavelength channels, and being connected to the input source/filter for controlling the transmission of an optical signal associated with the data on the selected wavelength channel.

Abstract: An optical repolarizing device for transforming either a randomly polarized or unpolarized input beam into a polarized output beam. A polarization dependent beam splitter splits both polarization components of the incident signal and inserts them into an interferometer. In one arm of the interferometer, a polarization rotator, equivalent to a half waveplate, is inserted. In the other arm of the interferometer, a phase shifter is inserted. The phase shifter ensures that there are no delays between the signals in the two interferometer arms, and thus there is constructive interference when the two beams, now having the same polarization, recombine at the output of the interferometer, where a beam combiner is provided for this purpose. For unpolarized input light, the phase shifter is unnecessary.

Abstract: A tunable phase mask assembly for use in photoinducing an optical wavelength filter in an optical waveguide. The phase mask assembly includes a phase mask having a length extending between two opposite longitudinal ends. The phase mask has grating corrugations projecting from its surface and distributed with a periodicity along its length. The periodicity of the phase mask is tuned by reversibly changing its length between the two longitudinal ends, such as by compressing or stretching the mask. In this manner, the interference pattern of a light beam passing through the phase mask is also tuned, which allows to control the characteristics of a wavelength filter photoinduced using this phase mask assembly.

Abstract: The present invention concerns a method for fabricating a patterned, poled dielectric structure, comprising the steps of providing a material, patterning a periodic pattern into a first surface, applying an electrode to the first surface, and applying a voltage to the electrode to create a domain inversion in the material. Preferably, the material is a ferroelectric material, and the electrode is a single, planar, solid electrode. The method proposed herein is simple, reproducible and economical, as compared to prior methods. Patterned, poled dielectric structures are used to generate optical frequency conversion, by creating quasi-phase matching between two optical signals.

Abstract: An optical fiber comprises a singlemode core, and an inner cladding disposed around said core, an intermediate cladding disposed around said inner cladding and an outer cladding disposed around said intermediate cladding thereby forming a triple-clad geometry. The core is doped with rare-earth elements and represents the waveguide section of higher refractive index through which the signal is transmitted and amplified. A fiber coating is provided around said outer cladding. The core has a higher refractive index than said inner cladding, said inner cladding having a higher refractive index than said intermediate cladding, and said intermediate cladding having a higher refractive index than said outer cladding. The inner cladding has a fairly high refractive index to limit the numerical aperture (NA) of said core.

Abstract: A tunable phase mask assembly for use in photoinducing an optical wavelength filter in an optical waveguide. The phase mask assembly includes a phase mask having a length extending between two opposite longitudinal ends. The phase mask has grating corrugations projecting from its surface and distributed with a periodicity along its length. The periodicity of the phase mask is tuned by reversibly changing its length between the two longitudinal ends, such as by compressing or stretching the mask. In this manner, the interference pattern of a light beam passing through the phase mask is also tuned, which allows to control the characteristics of a wavelength filter photoinduced using this phase mask assembly.

Abstract: A wavelength tunable optolelectronic device. Two channel waveguides are provided in an optoelectronic structure made of a ferroelectric material. The waveguides are adjacent along at least a coupling region. A periodically poled structure is provided in the coupling region, and at least one of the waveguides is untouched by this structure. An electric field is applied in the coupling region, through both waveguides, to enable coupling a light of a given wavelength between the two waveguides. The amplitude of the electric field may be selected to tune the coupling wavelength. A third waveguide or more having a coupling region in common with the second waveguide may also be added to allow the bandwidth of the resulting beam to also be tuned.

Abstract: A wavelength tunable optolelectronic device. Two channel waveguides are provided in an optoelectronic structure made of a ferroelectric material. The wave-guides are adjacent along at least a coupling region. A periodically poled structure is provided in the coupling region, and at least one of the waveguides is untouched by this structure. An electric field is applied in the coupling region, through both waveguides, to enable coupling a light of a given wavelength between the two waveguides. The amplitude of the electric field may be selected to tune the coupling wavelength. A third waveguide or more having a coupling region in common with the second waveguide may also be added to allow the bandwidth of the resulting beam to also be tuned.

Abstract: The present invention concerns a method for fabricating a patterned, poled dielectric structure, comprising the steps of providing a material, patterning a periodic pattern into a first surface, applying an electrode to the first surface, and applying a voltage to the electrode to create a domain inversion in the material. Preferably, the material is a ferroelectric material, and the electrode is a single, planar, solid electrode. The method proposed herein is simple, reproducible and economical, as compared to prior methods. Patterned, poled dielectric structures are used to generate optical frequency conversion, by creating quasi-phase matching between two optical signals.

Abstract: An optical fiber pumping apparatus for use with a double-cladding fiber in an optical amplifier or laser configuration comprises a plurality of laser diodes used as pump sources disposed in a spatial configuration for radiating pump energy along an optical axis through a surrounding generally annular area, leaving an available middle area. The apparatus further comprises an optical coupling device having an optical input portion generally aligned with the optical axis to collect the pump energy and having an optical output portion aligned with the pumping input portion for transferring the pump energy to the inner cladding surrounding the doped core of the fiber. The apparatus exhibits high pump power rating and allows efficient input signal coupling in optical fiber amplifier applications. According to the different preferred embodiments, the apparatus can act either simultaneously or independently as a pump combiner, multiple pump injector, signal coupler or pump/signal multiplexer/demultiplexer.

Abstract: A low-cost superfluorescent fiber souce. A gain medium in a length of optical fiber is pumped in counter-propagation by a pump source, producing superfluorescent radiation. The pump source is coupled to the fiber by a first coupler, disposed forward of the gain medium, that selectively transmits the pump signal in the backward direction, and the superfluorescence in the forward direction. A second coupler is disposed backward of the gain medium, selectively transmitting the backward propagating superfluorescent radiation along a first path and the pump signal along a second path, the pump signal is absorbed in the second path by a high-attenuation fiber, to avoid feedback to the pump laser, and the superfuorescent is reflected in the first path back toward the source output. Advantageously, this source can be realized with readily available optical components that are easy to assemble and do not require any alignment.

Abstract: An optical coupling device is provided. The device is based on a substrate in which two channel waveguides are provided. A coupling region is defined in the substrate through which both waveguides lie adjacent to each other. A periodic refractive index change is permanently provided in the coupling region. The periodic refractive index change permanently has a period &Lgr; and enables a coupling between the waveguides of light having a coupling wavelength &lgr;=&Lgr;(neff1-neff2), where neff1 and neff2 are average refractive index values of the respective waveguides along the coupling region, neff1 being different from neff2. An electric field may be applied to the coupling region to allow a tuning of the coupling wavelength.

Abstract: A gain-locked dual stage or multi stage optical amplifier. The input signal is injected into an optical waveguide, such as an optical fiber, provided with at least a first and a second amplifying stage. Each amplifying stage is pumped by a corresponding pump source producing a pump signal having an initial pump power value. Means are provided to monitor the initial pump power of the first pump source, the initial pump power of the second pump source and the pump power of the portion of this signal unabsorbed by the first amplifying stage. The initial pump power of the first and second pump signals are controlled together, being set to a same controlled value which is calculated based on the pump power of the unabsorbed signal from the first amplifying stage.

Abstract: A method and an apparatus to photoinduce a grating or other type of modulated refractive index change in a photosensitive optical medium such as optical fiber. The resulting grating has a variable and controllable intensity profile and average value of the index change. The modulated refractive index change is photoimprinted in the medium in a series of writing steps, each comprising exposing a segment of the medium to a writing beam for a predetermined exposure time. To change the modulation intensity from step to step, the angle of incidence of the writing beam is dithered for an appropriate fraction of the exposure time at each step. This allows to control the amount of incident light on the medium for each step. If the exposure time is the same for each writing step, the average value of the index change may be kept constant avoiding undesired structure in the grating frequency response.

Abstract: The amplifier is a two-stage amplifier in which dispersion compensation and WDM channel equalization are carried out using a plurality of in-waveguide Bragg gratings placed between the two stages. The first stage has a gain able to raise the intensity of WDM optical communications signals to a high enough level that after dispersion compensation and equalization, the signals fed into the second stage nearly or substantially saturate the second stage amplifier. The noise figure signal-to-noise ratio is thereby of good quality since there are no significant losses at the signal input of the signal into the optical amplifier. Erbium-doped optically pumped fiber amplifiers are used for the two stages. An add/drop filter can be appended to the end of the conditioning Bragg gratings. Residual optical signal from the fiber Bragg grating may be used to optically pump another amplifier for amplifying longer wavelength optical signals.

Abstract: A method for spatially controlling the period and amplitude of Bragg filters in an optical medium having a longitudinal axis that is sensitive to at least some wavelength of electromagnetic radiation. A phase mask of period .LAMBDA. is laid close to the optical medium at an angle .alpha. with respect to the longitudinal axis of the optical medium. A single beam of electromagnetic radiation is directed at an incidence angle .phi. with respect to normal incidence on the phase mask so that the radiation is diffracted, resulting in an interference pattern having a period P impinged into the optical medium so that the period P of the interference pattern may be altered by changing the incidence angle .phi. or the angle .alpha.. This method is simpler, more flexible and more suitable for mass production than existing methods.