Abstract: Phosphate free, Er/Yb co-doped borosilicate glass compositions and optical devices made from said compositions are disclosed; said compositions comprising, for 100 parts by weight of: 60 to 70 parts by weight SiO2 or SiO2+GeO2 with SiO2 always being greater than 40 parts by weight, 8 to 12 parts by weight of B2O3, 10 to 25 parts by weight M2O wherein M2O is an alkali metal oxide, 0 to 3 parts by weight of BaO, 0.1 to 5 parts by weight Er2O3, and from 0.1 to 12 parts by weight of Yb2O3 and from 0 to less than 5 parts by weight F; and within which, the boron atoms are of tetrahedral spatial coordination.

Abstract: According to one aspect of the present invention an optically active glass contains Sb2O3, up to about 4 mole % of an oxide of a rare earth element, and 0-20 mole % of a metal halide selected from the group consisting of a metal fluoride, a metal bromide, a metal chloride, and mixtures thereof, wherein this metal is a trivalent metal, a divalent metal, a monovalent metal, and mixtures thereof. In addition, any of the glass compositions described herein may contain up to 15 mole % B2O3 substituted for an equivalent amount of Sb2O3.

Abstract: Disclosed is a tunable optical filter which may be used in telecommunications systems. The filter comprises a single mode optical waveguide containing a grating. The resonance wavelength of the filter is changed by changing the boundary condition at the interface between the cladding layer and an additional layer applied to the outer cladding layer surface. This boundary condition is changed by changing the refractive index of the additional layer. Means for changing the refractive index of the additional layer include establishing a structural resonance in the additional layer, or forming the additional layer from electro-optic or piezoelectric materials.

Abstract: An apparatus is provided for mechanically attaching an optical fiber to a substrate. The apparatus includes a clamping block formed of malleable material disposed adjacent a substrate. The fiber is disposed adjacent the clamping block and a securing member such as a fastener or spring is used to secure the fiber to the clamping block and substrate. The frictional forces between the fiber and the clamping block eliminate movement of the fiber relative to the substrate.

Abstract: An L-band optical amplifier has a rare earth doped gain medium including a filter distributed over a finite physical portion of the gain medium. The filter is distributed over between about 25% to substantially the entire length of the gain medium. The distributed filter substantially eliminates out-of-band light emission (C-band ASE, 1520 nm-1565 nm) and thus improves the performance of L-band amplification (1565 nm-1620 nm). Examples of distributed filters include discrete type filters such as long period gratings, or continuous type filters such as rare earth doped, twin core fibers, non-adiabatically tapered fibers and coaxial resonant ring fibers.

Abstract: An optical amplifier comprises an optical fiber segment doped with impurity ions such as erbium for providing optical gain for an optical signal propagating in the optical fiber segment. A first source of a first pumping wavelength pumps the ions from a first ground state to a second metastable state. The metastable state decays to the ground state by stimulated emission to provide the optical gain. A second source of a second pumping wavelength pumps the ions from the ground state to a third auxiliary state. The auxiliary state decays to the metastable state. Thus, by controlling the pumping power in one or both pumping wavelengths, it is possible to control the fraction of ions in the metastable state. This in turn permits control of an overall scale factor of the gain spectrum without substantially affecting the shape of the gain spectrum.

Abstract: A method of forming a joint comprises the steps of: (a) at least filling a container with granular particles, the granular particles having a size of 0.25 mm to 1 mm; (b) inserting a component part into the container; and (c) at least partially filling the container containing this component part and the granular particles with a flowable, curable liquid, this liquid having curing time of less than 90 seconds. According to one embodiment of the present invention, the curable liquid has a gap fill of less than 0.25 mm and the curing time is less than about 5 seconds or less.

Abstract: An optical amplifier comprises: 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 gain medium is an optical fiber of a predetermined length, such that inversion of this first gain medium is not saturated. 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. According to an embodiment of the present invention the predetermined length of the optical fiber of the first gain medium is 1 to 6 meters and preferably 1.5 to 4.5 meters.

Abstract: The invention includes methods of stabilizing negative thermal expansion glass-ceramic optical waveguide substrates. The invention includes the stabilized negative thermal expansion glass-ceramic optical waveguide substrates. The stabilized substrates have very stable physical characteristics such as dimensional length when exposed to extreme environments. The stabilized substrates are used to athermalize optical waveguide devices such as optical fiber grating. The stabilized substrates are particularly well suited for providing athermalized fiber Bragg grating.

Abstract: A multi-amplification path optical amplifier including a first amplification path for propagating and amplifying a first in-band optical communication signal, including a spectrally selective filter for substantially blocking the propagation and amplification of an out-of-band optical communication signal along the first amplification path, and a second amplification path for propagating and amplifying a second in-band optical communication signal, including a spectrally selective filter for substantially blocking the propagation and amplification of an out-of-band optical communication signal along the second amplification path, wherein the location. If the spectrally selective filters in each respective amplification path is selected so that a target noise figure performance and a target output power performance can be obtained from the device. The spectrally selective insertion losses suppress crosstalk or optical leakage that gives rise to multipath interference, return loss, and self oscillation.

Abstract: The invention is directed to a multistage optical amplifier having a gain stage between two gain flattening filters. According to illustrative embodiments, a gain flattened optical amplifier system comprises a plurality of optical gain stages and a plurality of gain flattening filter stages arranged serially in an alternating manner.

Abstract: Techniques for controlling the shape of the gain spectrum of an optical amplifier (13) based on the temperature and level of inversion of the amplifier's amplifying medium (20) are provided. An increase in temperature for an amplifying medium having a high level of inversion results in an increase in gain for longer wavelengths relative to shorter wavelengths, i.e., a counterclockwise tilt of the gain spectrum, while an increase in temperature for an amplifying medium having a lower level of inversion results in the opposite effect, i.e., a clockwise tilt. These effects can be used to compensate for changes in the operating conditions of the amplifier, e.g., to compensate for changes in signal powers. The effects of thermal tuning are especially useful in WDM systems employing multi-stage amplifiers.

Abstract: An amplifier system includes: (i) a distributed Raman fiber amplifier adapted to amplify C and L-band signals and; (ii) a discrete Raman fiber amplifier module that includes a C-band amplification stage and an L-band amplification stage. The discrete Raman fiber amplifier module is operatively connected to the distributed Raman fiber amplifier and amplifies signals received from the distributed Raman fiber amplifier. In one embodiment the distributed Raman fiber amplifier and the discrete Raman fiber amplifier share optical pump power provided by the shared pump.

Abstract: A method for printing images on a recording material by way of at least two multimode laser beams created by emitting apertures of at least two multimode lasers includes the steps of: forming with each of said multimode lasers a spot having a long dimension and a short dimension with each of the multimode laser beams such that the long dimension of each of the spots corresponds to a long dimension of a respective emitting aperture of each of the multimode lasers; and scanning the spots created by the multimode laser beams across the recording material such that (i) the long dimension of each of the spots is parallel to scan direction, and (ii) so as to create a series of spaced apart swaths, each of which has a plurality of image lines, the spacings between the image lines of a swath being different from spacing between two adjacent swaths.

Abstract: An amplification stage of a multistage, rare earth doped optical amplifier, having a gain spectrum including a shorter wavelength band and a longer wavelength band, provided with excitation light produces an amount of ASE traveling in a reverse direction to the initial excitation light. The reverse traveling ASE light is directed to another amplification stage of the amplifier and substantially provides excitation light for pumping the longer wavelength band. The proposed amplifier structure and associated method of optical signal amplification efficiently utilizes unavoidable ASE light for optical signal amplification. The invention provides signal amplification in a wavelength band not heretofore efficiently utilized in conventional rare earth doped optical amplifiers.

Abstract: A length of oxynitride optical fiber is exposed to actinic radiation that is modulated by an interference technique to form a pattern of refractive index variations that functions as a reflective grating.

Abstract: A light source device includes a housing forming a cavity with a diffusely light reflective interior surface and an exit port; at least one LED on the interior surface; a light reflective layer and an electrically and thermally conductive layer between the LED and the housing; electrical contacts interconnecting the LED and the outside of the housing, such that electrical power applied to the contacts causes the LED to emit light.

Abstract: The invention is directed to a multistage optical amplifier having a gain stage between a GFF and an optical attenuator. More specifically, in accordance with an illustrative embodiment of the present invention, an optical amplifier system comprises multiple gain stages arranged serially for providing gain to an optical signal propagating therein. The system also includes a gain flattening filter for reducing a variation in gain of the optical amplifier system in a particular wavelength band and an optical attenuation element. One of the gain stages is located between the gain flattening filter and the optical attenuation element to reduce an overall noise factor of the optical amplifier system. Illustratively, each gain stage is a pumped segment of erbium doped optical fiber. The optical attenuation element may precede the gain flattening filter in a direction of propagation of an optical signal in the amplifier system.

Abstract: The method for positioning an array with periodic structures, for forming an image thereon, comprises the following steps: (a) providing a first beam of light by a first light source; (b) passing this first beam of light through the array; (c) forming a light line corresponding to the first light source with the first beam of light after the first beam of light passes through the array such that the light line is perpendicular to long axes of the periodic structures; (d) rotating the array to rotate the light line across a first detector; (e) producing a signal when the light line sweeps across the first detector; (f) determining when maximum signal is produced by the first detector; and (g) rotating the array to a proper position based on angular position corresponding to this maximum signal.

Abstract: According to one aspect of the present invention a method for increasing intensity of a polarized multimode laser beam including the steps of: (i) changing polarization of a portion of a cross section of the multimode laser beam, so that the cross section of this multimode laser beam comprises a first portion with one polarization and a second portion with a polarization that is different from this one polarization; and (ii) at least partially superimposing the first portion of the cross section of the multimode laser beam onto the second portion of the cross section of the multimode laser beam, thereby forming a superimposed laser beam.