Abstract: An optical fiber according to an embodiment of the present invention comprises: a glass core extending from a centerline to a radius R1 wherein R1 is greater than about 5 ?m; a glass cladding surrounding and in contact with the core, the cladding comprising: (i) a first annular region extending from the radius R1 to a radius R2, the first annular region comprising a radial width, W2=R2?R1, (ii) a second annular region extending from the radius R2 to a radius R3, and comprising a radial width, W3=R3?R2, and (iii) a third annular region surrounding the second annular region and extending from the radius R3 to an outermost glass radius R4; wherein the core comprises a maximum relative refractive index, ?1MAX, relative to the third annular region, and wherein ?1MAX is greater than about 0.1% and less than about 0.3%; the first annular region has a refractive index delta ?2(r) is less than about 0.

Abstract: In a distributed Raman amplification system, the pump laser and the fiber are chosen so as to have characteristics which result in broadening of the DRBS. For example, with a transmission fiber through which signal light of a wavelength &lgr;s propagates, and having zero dispersion at a wavelength &lgr;o; a pump laser producing counterpropagating pump light at a wavelength &lgr;p; where &lgr;p and &lgr;s are on opposite sides of the zero dispersion wavelength is used. The transmission fiber may be large effective area fiber. In a Raman amplification system suitable for use in a WDM optical fiber communication system, pump lasers having mode spacing which is less than the optical bandwidth of the signal channel have been found to be advantageous.

Abstract: The present invention relates to an optical fiber including a fiber core and at least one coating substantially encapsulating the fiber core, wherein the at least one coating includes a material forming a data storage medium which is capable of digitally encoding information at a data density of at least about 4 bits per centimeter. Both magnetically and optically encoded fibers are disclosed. Also disclosed are a method of making an optical fiber of the present invention, methods of digitally encoding information onto an optical fiber, and a method of retrieving information digitally encoded onto an optical fiber.

Abstract: There is proposed an optical amplifier apparatus particularly for use in networks distributing signals by optical fibers, comprising first and second parallel optical branches (1, 2), the first optical branch (1) including optical amplifier means (5, 6) for amplifying digital signals and the second optical branch including optical amplifier means (7) for amplifying analogue signals, the optical amplifier means (5, 6) of the first optical path (1) being adapted to amplify bidirectional digital signals and the optical amplifier means (7) of the second optical branch (2) being adapted to amplify unidirectional analogue signals.

Abstract: A method of providing a predetermined insertion loss in an optical fiber amplifier, includes the step of utilizing a predetermined, fixed, spectrally-flat loss compound (insertion loss pad, ILP) to pad total optical fiber amplifier insertion loss up to a predetermined fixed level.

Abstract: An optical signal amplifier includes a Raman fiber amplifier and a semiconductor optical amplifier. The Raman fiber amplifier utilizes pump radiation to amplify the optical signal resulting in an amplified optical signal. The semiconductor optical amplifier receives the amplified signal amplifying the amplified signal resulting in a twice amplified signal.

Abstract: A wavelength division demultiplexer includes a channel dropping component for receiving optical signals transmitted through a plurality of optical channels, defined by successively different light wavelength bands at intervals ranging between a first channel having the lowest wavelength band to a last channel having the highest wavelength band. The channel dropping component separates at least one channel having a wavelength band intermediate the lowest wavelength band and the highest wavelength band. The demultiplexer further includes an edge filter for separating optical signals received from the channel dropping component that have wavelengths below the intermediate wavelength band from optical signals having wavelengths above the intermediate wavelength band. The separated optical signals are transmitted from the edge filter in two different optical paths.

Abstract: An optical amplifier comprises a trivalent thulium-doped optical fiber; a first pump light emitting device optically coupled to the fiber for generating a primary pump source at a first wavelength, and a second pump light emitting device optically coupled to the fiber for generating a secondary pump source at a second wavelength. In a preferred aspect of the present invention, the amplifier also includes a third (auxiliary) pump light emitting device optically coupled to the fiber for generating a third pump source at a third wavelength. Each of the amplification signals comprise at least one pre-selected wavelength. The first amplification signal has a wavelength pre-selected to provide a reduced noise figure for the amplifier. The second amplification signal has a wavelength pre-selected to increase the optical efficiency of the amplifier. The third amplification signal can have a wavelength pre-selected to populate the 3F4 energy level of the fiber, and to minimize depletion of the 3H6 ground state.

Abstract: A method of assembling an optical system includes the steps of: (i) selecting, from a plurality of optical fibers characterized by a common nominal cut-off wavelength &lgr;cn and an actual cut-off wavelength &lgr;c such that the cut-off wavelength &lgr;c of each one of this plurality of fibers is the same as the nominal cut-off wavelength &lgr;cn or differs slightly from the nominal cut-off wavelength due to manufacturing tolerances, only fibers with &lgr;c>&lgr;min, where &lgr;min is a predetermined minimum acceptable cut-off wavelength of the selected fibers; and (ii) bending at least one section of at least one of these selected fibers such that this bent section has a bend radius R, where 12 mm<R<18 mm.

Abstract: The invention includes environmentally stable athermalized optical fiber gratings and methods of making such stabilized optical waveguide fiber grating. Stable humidity-resistant athermalized fiber Bragg gratings are provided by stabilizing a negative thermal expansion substrate and utilizing a durable frit to attach the fiber Bragg grating to the substrate.

Abstract: An athermal optical device and a method for producing the device, such as an athermal optical fiber reflective grating, are described. The athermal optical fiber reflective grating device comprises a negative expansion substrate, an optical fiber mounted on the substrate surface, and a grating defined in the optical fiber. The method for producing the athermal optical fiber reflective grating device comprises providing a negative expansion substrate, mounting an optical fiber with at least one reflective grating defined therein onto the substrate upper surface, and affixing the optical fiber to the substrate at at least two spaced apart locations.

Abstract: Compound gain flattening filters of optical amplification include a series of filter components with spectral responses that are combined to approach a target loss spectrum. Small variations in the central wavelengths of the component responses can produce large errors in the combined response of the compound gain flattening filter. However, the components can be divided into sub-components with balanced central wavelength deviations to achieve the desired response goals despite exhibiting otherwise detrimental wavelength deviations.

Abstract: A multi-stage optical fiber amplifier comprises a first gain stage amplifying and optical signal; a pumping source coupled to the first gain stage, a second gain stage coupled to the first gain to further amplifying the optical signal to a desired output signal power, and a second pumping source coupled to the second gain stage. The second pumping source is preferably an erbium-doped fiber laser and has an operating wavelength between about 1520 nm and about 1620 nm. This amplifier achieves good noise figure and high output powers.

Abstract: The optical amplifier includes a first gain medium having an optical host that contains a rare earth dopant and a first pump that supplies optical energy at a first wavelength into this first gain medium. The first pump operates at a pump wavelength that has a lower inversion saturation than the highest wavelength of absorption of the first gain medium. The optical amplifier further comprises a second gain medium operatively coupled to the first gain medium and a second pump that supplies optical energy into the second gain medium.

Abstract: The present invention relates to an optical amplifier system in which multiple laser cavities are utilized to control the gain of an erbium doped fiber amplifier (EDFA). More specifically, the present invention is directed to an optical amplifier comprising a gain medium such as an erbium doped optical fiber which provides gain for an optical signal propagating therein. The gain medium also provides gain for a plurality of laser cavities (e.g. first and second laser cavities) which simultaneously oscillate at individual (e.g. first and second) wavelengths. The inventive optical amplifier results in reduced variation in gain spectrum as a function of input signal power, as a function of wavelength, and as a function of time. By varying the optical attenuation in one or more of the individual laser cavities it is possible to vary the gain spectrum of the gain medium at the corresponding individual wavelength and this controls the shape of the gain spectrum of the gain medium.

Abstract: An optical waveguide optical amplifier device for use with an optical telecommunications system that transmits optically amplifiable subscriber channels and communicates service information internally within the system with optical service channels and includes an optical amplifier input, an amplifier output, and optical amplifier medium. The optical amplifier input includes a reflective isolator longitudinal body with a first end and a second end. The first end includes an input fiber for receiving the subscriber and optical service channels inputted into the amplifier input and an output fiber for transmitting the subscriber channels to the amplifier medium. The second end of the reflective isolator body includes an optical service channel accessor which guides the subscriber channels to the output optical fiber.

Abstract: An optical device is provided including a substrate having an underclad layer, a core layer, and a pair of overclad layers deposited thereon. The substrate has a first coefficient of thermal expansion. The underclad layer has a first index of refraction. The first overclad layer has an index of refraction which is approximately equal to the first index of refraction. The second overclad layer has a coefficient of thermal expansion which is greater than the first coefficient of thermal expansion.

Abstract: An optical signal limiter is provided for limiting transmission of a continuous wave optical signal that exceeds a preselected threshold power level. The limiter includes a body having input and output ends that is formed at least in part from a material having a negative thermal index coefficient of between about −0.5×10−4 °C.−1 and −4.0×10−4 °C.−1 and an absorption coefficient of between 1.0 to 5.0 dB/cm at wavelengths between 980-1650 nm. The limiter also includes collimating fibers mounted on the input and output ends to minimize low power signal losses across the limiter body. It may be installed at a junction between two optical fibers and is preferably formed from a curable adhesive having the aforementioned negative thermal index coefficient to obviate the need for separate bonding materials and joining steps during the installation of the limiter.

Abstract: A glass consisting essentially of antimony oxide. An optically active glass consisting essentially of antimony oxide and up to about 4 mole % of an oxide of a rare earth element. A rare earth-doped, antimony oxide-containing glass including 0-99 mole % SiO2, 0-99 mole % GeO2, 0-75 mole % (Al, Ga)2O3, 0.5-99 mole % Sb2O3, and up to about 4 mole % of an oxide of a rare earth element. The oxide of the rare earth element may comprise Er2O3. The glass of the invention further includes fluorine, expressed as a metal fluoride. An optical energy-producing or light-amplifying device, in particular, an optical amplifier, comprising the above-described glass. The optical amplifier can be either a fiber amplifier or a planar amplifier, either of which may have a hybrid composition. Embodiments of the glass of the invention can be formed by conventional glass making techniques, while some of the high content antimony oxide embodiments are formed by splat or roller quenching.

Abstract: Apparatus for packaging a fiber optic device along with electronic and opto-electronic components upon a printed circuit board. Bend members having arcuate shaped guide surfaces for directing fibers between various components are strategically mounted upon the top surface of the board. Passive fiber optic components are also mounted upon support means between bend members so that the fibers entering and exiting the passive component run tangent to the bend radius of the bend members. The radius of curvature of the bend members is within the bend tolerance of the fibers used in the device. The bend members and support members are formed of a material having a thermal coefficient of expansion that is about equal to that of the board material whereby thermally induced stresses on the board mounted components are minimized.