Lucent Technologies Inc.

At&t Bell Laboratories

At+t Corp.

Other

Ofs Fitel, LLC

Fitel USA Corporation

Robert M Atkins

Victor Mizrahi

George E Peterson

Kenneth L Walker

Paul Joseph Lemaire

Raymond D Tuminaro

Jean-Marc P Delavaux

James William Fleming

Rolando Patricio Espindola

Debra A Simoff

Herman M Presby

Man Fei Yan

Francis Michael Houlihan

Robert Scott Windeler

Arturo Hale

Valerie Jeanne Kuck

Fred P Partus

Gordon Albert Thomas

Poul Kristensen

Alice Weimin Liu

Mark Anthony Paczkowski

Benjamin Irvin Greene

Chellappan Narayanan

Paul Francis Glodis

Stig Nissen Knudsen

Kai H Chang

Richard Tobias Olsson

Jake Bromage

Morten Østergaard Pedersen

Jan Levin Nielsen

The specification describes methods for the manufacture of very large optical fiber preforms wherein the core material is produced by MCVD. Previous limitations on preform size inherent in having the MCVD starting tube as part of the preform process are eliminated by removing the MCVD starting tube material from the collapsed MCVD rod by etching or mechanical grinding. Doped overcladding tubes are used to provide the outer segments of the refractive index profile thus making most effective use of the MCVD produced glass and allowing the production of significantly larger MCVD preforms than previously possible.

MCVD optical fiber method with partial removal of substrate tube

Early stage detection of engine liquid cooling problems is provided with temperature, pressure and other sensors and associated logic circuits configured for detecting alarm conditions including below normal static coolant pressure coupled with an elevated coolant temperature, above normal static coolant pressure, below normal coolant pump pressure condition, coolant voids due to coolant loss or boiling, and external steam or liquid leakage from the cooling system. A gauge displays the difference between coolant pump output pressure and static coolant pressure.

Monitoring of closed circuit liquid cooling systems particularly in internal combustion engines

Applicants have discovered the existence of loss peaks in optical fiber transmission systems using wavelengths in the E-band and the L-band. Specifically, they have discovered the existence of narrow loss peaks at 1440 nm, 1583 nm and 1614 nm. Because the peaks are relatively narrow, they cannot be easily removed by conventional gain equalizers in long haul transmission systems, and although the peaks are relatively small, they can nonetheless cause transmission channels to drop out in amplified DWDM transmission systems. Applicants have further discovered that these loss peaks are due to carbon contamination of the transmission fiber. Thus optical fibers should be fabricated essentially free of carbon contamination. This means eliminating carbon-containing reagents in preform and tube-making processes.

Method of making optical fiber with reduced E-band and L-band loss peaks

A cooling system for conversion of air cooled aircraft engines to liquid cooling, including replacement cylinders, light weight, flex tolerant coolant manifolds and cooling system instrumentation for monitoring coolant temperature and pressure. The replacement cylinders have internal gating of coolant flow between a cylinder jacket and cylinder head exhaust port cooling passages for continuous high power operation of the engine.

Liquid cooling system and retrofit for horizontally opposed air cooled piston aircraft engines

This invention is predicated upon applicants' discovery that UV-induced gratings can be formed through polymer coatings that include conjugated double bonds and aromatic moieties. Coatings with low concentrations of aromatic-containing free-radical photoinitiators provide both reasonable curing speeds and sufficient transparency that gratings can be written through them. Moreover some of these aromatic-containing free-radical photoinitiators act synergistically with non-aromatic ketone photoinitiators. Advantageous aromatic-containing free-radical photoinitiator concentrations are in the range 0.01%-0.1% and preferably in the range 0.02% to 0.05%. Advantageous polymer coatings are acrylate-based coatings.

Formation of gratings in optical fibers coated with UV-curable polymer

Applicants have determined that much of the nonuniformity in solution doped preforms is due to nonuniformity of the soot layer caused by the high temperature necessary for complete reaction, and that MCVD fabrication using reaction temperature lowering gases such as nitrous oxide (N.sub.2 O) can produce more uniform soot layers. The conventional oxygen/reactant gas mixture presents a very small temperature window in which a uniform silica soot layer can be deposited without sintering. If the temperature in oxygen is too low, SiCl.sub.4 will not react completely and silicon oxychlorides will form. This degrades the soot layer and makes it unusable. If the temperature is too high the soot layer begins to sinter, decreasing the surface area and porosity. Adding a reaction temperature lowering gas lowers the reaction temperature and enables deposition of soot on the tube wall at a temperature substantially lower than the sintering temperature. This results in a more uniform, porous soot layer along the length of the preform and from one preform to another; and, in turn, the greater uniformity permits more uniform solution doping.

Method of making optical waveguide devices using perchloryl fluoride to

In accordance with the invention, the index of refraction of a region of a glass body is selectively increased by treating the glass with hydrogen or deuterium, heating the hydrogenated glass to a temperature in excess of 500.degree. C., permitting the glass to rapidly cool below 100.degree. C. and exposing the region to UV radiation, preferably in the range 300 nm to 400 nm. The result is an increase in the refractive index of the irradiated region. Absorption is via a GODC band at 330 nm believed to result from a singlet to triplet transition. This band is about 1000 times weaker than the commonly used band at 240 nm. This process can be used to make and adjust a variety of optical waveguide devices such as photoinduced Bragg gratings and long period gratings.

Method for producing photo induced grating devices by UV irradiation of

A method is provided of trimming the optical coupling ratio of an optical coupler to a prescribed value. The optical coupler is formed from a plurality of waveguides which each include a core and cladding. In accordance with the method, an irradiation energy is selected that is absorbed by portions of the waveguides located in a coupling region. A dosage of radiation is applied to the waveguide portions at least sufficient to adjust the optical coupling ratio to the prescribed value. The radiation, which may be absorbed by the cladding and/or the core of the waveguides, causes a change in the refractive index difference between the core and cladding of the waveguides. This change in the refractive index difference will result in a change in the optical coupling ratio of the device.

Radiolytic method for trimming planar waveguide couplers

The method of making an optical fiber refractive index grating comprises writing the grating through the fiber coating. The method involves providing optical fiber of significantly higher photosensitivity than conventional fiber, such that the grating can be written before unacceptable darkening of the coating occurs. Such fiber is H.sub.2 and/or D.sub.2 -loaded silica-based fiber having a Ge-doped core, the fiber selected to have a germanium-oxygen deficiency center content that provides the fiber with a photosensitivity that is at least twice as large as that of an otherwise identical, conventionally prepared, optical fiber. The fiber typically is drawn from a preform, at least a portion of which was exposed to a reducing atmosphere at an elevated temperature.

Method of making an optical fiber grating, and article made by the method

An optical fiber formed from a glass preform substantially free of OH impurities is disclosed. The optical fiber is made to be free of OH impurities by a method having the steps of introducing a moving stream of vapor mixture including at least one compound glass-forming precursor together with an oxidizing medium into a tube, while generating a hydrogen-fee isothermal plasma on an outer surface of the tube to react the mixture and produce a glassy deposit on an inner surface of the tube. The glass preform is drawn to produce the optical fiber.

Optical fiber with low OH impurity and communication system using the

In accordance with the invention, the index of refraction of a glassy material is increased by treating the material with hydrogen and applying heat. Specifically, the glass is exposed to hydrogen or deuterium at pressure in the range 14-11,000 p.s.i. and a temperature in the range 21.degree.-150.degree. C. for a time sufficient for the hydrogen to diffuse into the glass. The glass is then subjected to heat in excess of about 500.degree. C., as by application of a flame or infrared radiation. The duration of heating can be less than a second. The result is a substantial and long-lived increase in the normalized refractive index. For example, flame heating of H.sub.2 loaded commercial GeO.sub.2 doped optical fibers (AT&T Accutether single mode fiber) has produced normalized index changes .increment.n/n of 4.times.10.sup.-3. This process can be used to make and adjust a variety of optical waveguide devices.

Method for increasing the index of refraction of a glassy material

We have discovered that at least some optical waveguide lasers such as Er-doped fiber lasers are subject to excessive output amplitude fluctuations, including severe fluctuations when the laser is subjected to mechanical shock. We have determined that these highly undesirable fluctuations are due to a resonance phenomenon, and that the fluctuations can be at least substantially reduced by means of a feedback loop that makes the amplitude of the output of the pump laser responsive to the amplitude of the output of the waveguide laser. We have also discovered that the operation of a pump laser/waveguide laser combination is frequently improved if an appropriate non-reciprocal element (e.g., an isolator or a tilted wavelength filter) is placed between the two lasers. An exemplary embodiment of the invention comprises the feedback loop as well as the non-reciprocal element.

Article comprising an optical waveguide laser

Described is a new method and apparatus for measuring the thickness of a thin conductive coating deposited on a moving elongated dielectric body. Of special use is an application of a carbon coating on an optical fiber. The thickness of the conductive coating is measured by establishing an electromagnetic field in a resonator including an elongated unshielded helix and a pair of coupling loops. The helix is suspended between the coupling loops out of contact with either one of them. An electromagnetic energy is coupled into one loop as an input signal from a source of electromagnetic energy and coupled out from the other loop as an output signal. The difference between the magnitude of energy of an empty helix or of a helix with an uncoated body, and the helix with a coated body, is used for controlling the coating process. The inner diameter of the helix is large relative to the diameter of the elongated body being at least five times the diameter of the fiber and the spacing between the coils of the helix being equal to the cross-sectional dimension of the rod, wire or tubing making up the coil. The general principles stated herein can be applied over a wide range of radio frequencies, typically from about 100 MHz to 100 GHz, and can be applied to a wide range of coating configurations by appropriately selecting a frequency range and equipment that is compatible with the selected frequency range.

Large aperture device for controlling thickness of conductive coatings

Unexpectedly large normalized refractive index changes (.DELTA.&gt;10.sup.-5, but possibly even larger than 10.sup.-3) can be obtained in oxide glass, e.g., high-silica glass, by a treatment that comprises exposing at least a portion of the glass at a temperature of at most 250.degree. C. to H.sub.2 or D.sub.2 (partial H.sub.2 or D.sub.2 pressure greater than 1 atmosphere), and irradiating at least a part of the exposed portion with actinic (typically UV) radiation. The method can be used to make optical components that comprise a region (or regions) of raised refractive index, e.g., an in-line refractive index grating in an optical waveguide, a planar optical waveguide, or a phase grating.

Growing community of inventors

Millington, NJ, United States of America

Robert M Atkins