Abstract: The invention relates to a process for treating a machined glass surface for improving the adhesive attachment of an optical fiber to this surface, characterized in that machined surface is attacked by an aqueous solution of hydrofluoric acid, then the attacked surface is treated with a bifunctional hydrolyzable silane adhesion promoter or the product of its hydrolysis and partial condensation.

Abstract: An optical fiber ribbon comprising a plurality of optical fibers secured or embedded substantially parallel to one another, fibers are selected and processed such that the skew in optical propagation time for signals transmitted over said plurality of optical fibers is minimized. The optical fibers are selected from the same pull and each of said optical fibers has a modal bandwidth greater than or equal to 800 Mhz.km at an operating wavelength of 1300 nm. The invention extends the practical applications of optical fiber ribbons to include synchronous parallel transmission with an aggregate data-rate.times.distance product of greater than 10 Gbit/sec.km.

Abstract: A device, utilized for the separation or combination of two signals of different wavelengths, of the type in which the waveguides comprise straight interaction segments (1.sub.1, 2.sub.1 ; 1.sub.in, 2.sub.in) parallel and close to one another and to curved approach segments with inflection points (1.sub.2, 2.sub.2, 1.sub.3, 2.sub.3 ; 1.sub.2n, 2.sub.2n, 1.sub.3n, 2.sub.3n), connected to the ends of the straight segments, and, for certain ones, to inputs/outputs (4,5,6) of the device. In accordance with the invention, the approach segments situated on at least the same side of the straight segments are free of any inflection point, the coupling of the straight segments being optionally modified to compensate for the variation of the coupling between the waveguides along said approach segments due to the omission of the inflection points.

Abstract: The present invention relates to an optical fiber component, which includes an optical component, (e.g., a glass tube), one or more glass optical fibers attached to the surface of said component, and a surface pretreatment layer, formed from a silane applied to the surfaces of the component and the one or more glass optical fibers. Preferably, an adhesive is applied over the surface pretreatment layer to strengthen attachment of the component to the one or more glass optical fibers. A method of preparing such optical fiber components is also disclosed.

Abstract: A device, utilized for the separation or combination of two signals of different wavelengths, of the type in which the waveguides comprise straight interaction segments (1.sub.1, 2.sub.1 ; 1.sub.1n, 2.sub.1n) parallel and close to one another and to curved approach segments with inflection points (1.sub.2, 2.sub.2, 1.sub.3, 2.sub.3 ; 1.sub.2n, 2.sub.2n, 1.sub.3n, 2.sub.3n), connected to the ends of the straight segments, and, for certain ones, to inputs/outputs (4, 5, 6) of the device. In accordance with the invention, the approach segments situated on at least the same side of the straight segments are free of any inflection point, the coupling of the straight segments being optionally modified to compensate for the variation of the coupling between the waveguides along said approach segments due to the omission of the inflection points.

Abstract: A method for monitoring the thickness of a hermetic coating on an optical waveguide fiber is provided in which an interference pattern is produced by illuminating the fiber with a laser beam. A spatial frequency spectrum is generated for the interference pattern and a first component of that spectrum, corresponding to the outside diameter of the fiber, is identified. The magnitude of this component is inversely related to the thickness of the coating, i.e., the magnitude decreases as the coating thickness increases, and thus this magnitude can be used to monitor the thickness of the coating during, for example, the coating process. Effects of fluctuations in the power of the laser beam and/or movement of the fiber relative to that beam can be minimized by normalizing the magnitude of the first component by the magnitude of the DC component of the spatial frequency spectrum.

Abstract: Disclosed is a family of dispersion compensating optical fibers that are adapted for use with conventional single-mode transmission fibers that are optimized for zero dispersion operation at a wavelength in the range from 1290 nm to 1330 nm to form a transmission link suitable for low dispersion operation in the 1520-1565 nm wavelength window. The dispersion compensating fibers are capable of providing a dispersion more negative than -20 ps/nm-km and attenuation less than 1 dB/km at wavelengths in the 1520-1565 nm region. Certain of the dispersion compensating fibers also exhibit a dispersion versus wavelength relationship having a negative slope in the 1520-1565 nm region, to compensate for the dispersion versus wavelength slope of the transmission fiber. The dispersion compensating fiber can be advantageously combined with a fiber amplifier to form a compensator that is adapted to overcome attenuation introduced into the system by the dispersion compensating fiber.

Abstract: The deleterious generation of hydrogen in optical fiber cables with cured silicone resin coatings is reduced by treating such optical fibers with one or more type of olefinic hydrocarbon to convert --Si--H groups remaining after curing to --Si--R groups where R is an alkyl group having the same number of carbons as the one or more type of olefinic hydrocarbon. The resulting optical fiber cable, having a light transmissive core surrounded by one or more glass cladding layers, is coated by a cured, silicone polymer having few, if any, residual --Si--H groups.

Abstract: Methods for measuring the diameters of transparent filaments with high precision, e.g., RMS standard deviations of less than 0.02 microns, are provided. The methods involve determining the average spatial frequency .omega. of the far-field interference pattern produced by illuminating the filament with a beam of laser light. The average spatial frequency is determined by performing a fast Fourier transform (FFT) on the interference data to obtain a coarse estimate for the average and then performing a set of discrete sequence Fourier transforms (DSFTs) in the region of the coarse estimate to obtain the desired high precision estimate of the average. Efficient on-line processing procedures are provided so that real time measurements can be performed on, for example, a moving optical waveguide fiber, at rates of 500 measurements/second and above.

Abstract: A splitter is produced by ion diffusion in a glass substrate and it is designed to assure the transmission of an optical signal toward two outputs with a predetermined ratio of the signal power appearing at these 2 outputs. In accordance with the invention, it comprises an X-junction of two rectilinear waveguides defining at their intersection a half-angle .alpha., the angle and the geometry of the central region being chosen in such a way as to establish the predetermined power ratio and the relative achromaticity of the device.

Abstract: A method of manufacturing and testing integrated optical composites in which fiber pigtails are aligned with and attached to the optical output ports of a plurality of integrated optical components on a wafer, prior to separation into individual components. The multiple pigtails are arranged at the ends opposite the wafer, to facilitate optical connections during active alignment and measurement testing.

Abstract: A method for measuring the diameter of a transparent filament is provided which is substantially insensitive to ellipticity of the filament. The method comprises using an interference technique to measure the filament diameter at two locations which are spaced apart by an amount such that a plot of diameter versus angle of rotation for an elliptical filament calculated at the first location is approximately 90.degree. out of phase from the same plot calculated at the second location. Due to the phase difference, the average of the two measurements is substantially insensitive to ellipticity. For measurement apparatus comprising one laser and two detectors and for optical waveguide fibers having a cladding composed of fused silica, the two locations can be about 123.degree. apart. In other embodiments, a method for characterizing the non-circularity of a filament is provided. Apparatus for practicing the foregoing methods is also disclosed.

Abstract: A process for the production of an integrated optical circuit in a glass body by ion exchange between certain regions of the glass body and a metallic salt with the use of a mask defining the regions where the ion exchange occurs, wherein the mask comprises a layer of silicon and the mask is removed by an etching operation preceded by a cleansing operation.

Abstract: Optical parts and optical equipment, including lenses, mirrors and laser media made of athermal glasses having compositions comprising 0-13 mol % CdO, 9-24 mol % CdF.sub.2, 5-10 mol % LiF, 30-34.5 mol % AlF.sub.3 28-33.5 mol % PbF.sub.2, 0-4 mol % KF, 0-6.5 mol % YF.sub.3, and 0-2 mol % LaF.sub.3 and having little or no optical path length change as a function of temperature in the infrared region of 1.mu.m to 5.mu.m.

Abstract: The coupler comprises two waveguides imbedded in a substrate and exhibiting a coupling region of length L establishing coupling coefficients (C.sub.1) and (C.sub.2) for the signals of the wavelengths (.lambda..sub.1) and (.lambda..sub.2) respectively. Following the invention, the length (L) and the coefficients (C.sub.1) and (C.sub.2) are linked by the relationship: ##EQU1## where n and m are integers, one uneven and the other even, chosen in such a manner as to establish a pass band of predetermined width (BP1, BP2) around at least one of the wavelengths (.lambda..sub.1) and (.lambda..sub.2). The invention has application to multiplexers/demultiplexers for optical fiber telecommunications.

Abstract: A planar optical waveguide comprises a substrate 1, a waveguide core layer 2, at least one planar optical element, wherein said planar optical element comprises at least one optically functional interface 3 which is adjacent to a cavity 4, and an overclad layer 5. The cavity enhances the optical characteristics of the planar optical element because of the substantial difference in the refractive index of the cavity as compared to the refractive index of said waveguide core layer.

Abstract: An optical waveguide fiber with a core region 1 and a cladding region 2, wherein the cladding region 2 includes an outer cladding region 3 is disclosed wherein the outer cladding region 3 is a very thin (less than 1 .mu.m in thickness) layer of TiO.sub.2 -SiO.sub.2 glass which results in a substantial reduction in the number of fiber breaks resulting from the fiber drawing process and having a predetermined TiO.sub.2 concentration less than or equal to about 10 wt. %. A method for making the fiber is also disclosed.

Abstract: An optical coupler with an input and 2.sup.n outputs comprises a plurality of substantially coplanar waveguides, each optically coupling said input to one of said 2.sup.n coupler outputs, said waveguides comprising a plurality of waveguide sections connecting n stages of Y-junctions disposed along each waveguide path in a tree and branch arrangement, and further comprises a first junction (J.sub.21), having an axis not parallel to that of said coupler, which is connected to two second junctions (J.sub.31, J.sub.32) by curved waveguide sections without singularities, wherein any inflection point along any one of the waveguides, between the input and the nth stage of the junctions, is situated at one of the n junctions along the waveguide path. The coupler may be successfully applied to splitters or combiners and carried out in integrated optics, and a method for designing the mask used in the manufacture of the integrated optics coupler is also described.

Abstract: A method and apparatus for rapidly forming a porous glass preform is provided in which an array of burners is oscillated along a path parallel to the longitudinal axis of the preform. Unlike existing soot deposition techniques, the oscillation amplitude is limited so that each burner deposits soot on only a portion of the preform, e.g., 20% of the preform. By controlling inter-burner variability and the air flow in the burner-array/preform region, preforms having substantially uniform axial properties are obtained notwithstanding the fact that different burners are used to laydown different parts of the preform.

Abstract: An improved method for making preforms by vapor deposition soot laydown processes is provided wherein an oxidizing atmosphere is used during at least part of the laydown process, e.g., during the laydown of the center portion of the preform. The use of such an atmosphere has been found to result in enhanced dopant capture, reduced axial trends, and an overall stabilization of the laydown process. A method for selecting burner flows which optimize the laydown process is also provided.