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Publication numberUSH1461 H
Publication typeGrant
Application numberUS 08/059,784
Publication dateJul 4, 1995
Filing dateMay 10, 1993
Priority dateMay 10, 1993
Publication number059784, 08059784, US H1461 H, US H1461H, US-H-H1461, USH1461 H, USH1461H
InventorsSam DiVita, John L. Margrave, Leif Fredin, Donald E. Patterson
Original AssigneeThe United States Of America As Represented By The Secretary Of The Army
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Abrasion resistant diamond like coating for optical fiber and method of forming the coating
US H1461 H
Abstract
A coating is provided for an optical fiber that inhibits abrasion or scraing of the fiber's surface. The coating is obtained by depositing a thin film of non-hydrogenated diamond-like amorphous carbon (a-C) onto the optical fiber using a laser ablation technique employing graphite as a target material.
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Claims(1)
What is claimed is:
1. An optical fiber with a thin inorganic abrasion resistant coating of a non-hydrogenated amorphous carbon that is extremely hard and slippery, with microhardness values above 3000 and coefficient of friction values below 0.2.
Description
GOVERNMENT INTEREST

The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalties thereon.

FIELD OF INVENTION

The invention relates to the art of coating an optical fiber, especially that of providing a coating that inhibits abrasion or scratching of the fiber's surface.

BACKGROUND OF THE INVENTION

Organic coatings are presently used to protect optical fibers from mechanical abrasion that leads to losses and mechanical failure via moisture and stress cracking. These soft coatings must be applied in thicknesses of tens of microns, and the coatings lack dimensional stability and become sticky with age. This causes failures, for example, when spooling the fiber for fiber optic-guided (FOG) missiles. The coatings have excessive volume and weight, limiting the missile range. Recently developed hermetic coatings for fibers provide protection against moisture attack, but do not provide protection against abrasion.

SUMMARY OF THE INVENTION

The general object of this invention is to provide a coating for an optical fiber that will provide abrasion resistance for the fiber as well as act as a chemical barrier for the fiber, with the coating being no greater than 1 micron in thickness. A further object of the invention is to provide such a coating that will provide many applications such as protecting germanium infrared windows from rain erosion and dust abrasion, and protecting magnetic disks from damage due to high speed contact with recording heads. A particular object of the invention is to provide a coated optical fiber wherein the coating provides excellent abrasion protection for electro-optical components such as silicon solar cells.

It has now been found that the foregoing objects can be attained by using diamond like coatings applied at or near room temperature. The coatings are extremely hard and slippery, with microhardness values above 3000 (Vickers) and coefficient of friction values below 0.2 when deposited under proper conditions. They are not attacked or permeated by moisture, brine, or any known acid or alkali at temperature below 100° C.

According to the method of the invention, it is possible to place a thin coating of non-hydrogenated diamond-like amorphous carbon (a-C) directly onto optical fibers with a laser ablation technique using graphite as a target material.

DESCRIPTION OF THE PREFERRED EMBODIMENT

More specifically, the method involves placing the substrate to be coated into an ultra-high vacuum (UHV, typically 10-8 Torr) chamber. A high intensity laser is then focused on a graphite target in the chamber. Various carbon species from the target are ablated off the target surface and deposited on optical fiber substrates placed in the path of the ablation plume. In this system, the deposited material is a form of a-C with a high sp3 bonded carbon content. An advantage of this method is that the fiber optic substrates do not have to be heated. This a-C coating offers superior adhesion, flexibility, and wear resistance. In fact, on coated pieces of quartz windows, the coating is impossible to remove with abrasive alumina polishing compounds while applying significant force.

In some instances, it may be desirable to coat the conventional optical fiber with a temporary abrasion resistant removable lubricating oil such as silicone oil, grease or benzene prior to spooling the hermetic coated or non hermetic optical fiber. This allows ease of winding or rewinding glass fiber on a spool or drum without breaking prior to applying the permanent abrasion resistant coating on the fiber.

In the method of the invention, the vacuum chamber allows for two or more graphite or graphite-like targets to be ablated with CO2 lasers for example to form a diamond or diamond like abrasion resistant coating on the surface of the fiber that is being drawn at the appropriate speed for complete coverage of the fiber as it is fed through the vacuum system prior to final spooling on the fiber.

Possible uses of the coated optical fibers of the invention include use as optical connectors, heat sinks for a high power optoelectronic device and related circuitry, high tensile strength optical fibers for fish sensing when coupled to fishing gear having a light emitting diode coupled to its fishing lure, abrasion resistant-glass containers for chemicals including household washing fluids, soda, and liquor bottles, coatings for smart skins in aircraft, bullet proof vests, abrasion resistant high strength, impact resistant structural materials, and use in borehole logging operation (that is, of an oil well), where the fiber must function for a useful lifetime under the extreme temperatures on the order of 200° C. and extreme pressures on the order of 20,000 psi that can be encountered in a typical oil well. It is important that inorganic abrasion resistant coating be used for non-hermetic coated fiber as well as hermetic, having appropriate abrasion resistant characteristics.

In lieu of the laser ablation technique disclosed in the description of the preferred embodiment, one might use other diposition methods to coat the optical fiber substrates as for example, a heater filament technique, a direct current discharge, a direct current plasma jet, an RF low pressure, a microwave technique, a flame heated gas technique, etc.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4735856 *Mar 31, 1986Apr 5, 1988Spectran CorporationHermetic coatings for optical fiber and product
JPH0243539A * Title not available
JPH0243540A * Title not available
JPH02309306A * Title not available
Referenced by
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US6696157Mar 5, 2000Feb 24, 20043M Innovative Properties CompanyDiamond-like glass thin films
US6795636Mar 5, 2000Sep 21, 20043M Innovative Properties CompanyRadiation-transmissive films on glass articles
US7106939Sep 17, 2002Sep 12, 20063M Innovative Properties CompanyOptical and optoelectronic articles
US7134381Aug 19, 2004Nov 14, 2006Nissan Motor Co., Ltd.Refrigerant compressor and friction control process therefor
US7146956Aug 6, 2004Dec 12, 2006Nissan Motor Co., Ltd.Valve train for internal combustion engine
US7181106 *Dec 4, 2003Feb 20, 2007Sumitomo Electric Industries, Ltd.Optical fiber capped at end with diffractive film, and manufacturing method therefor
US7255083May 2, 2005Aug 14, 2007Nissan Motor Co., Ltd.Sliding structure for automotive engine
US7273655Jan 12, 2005Sep 25, 2007Shojiro MiyakeSlidably movable member and method of producing same
US7284525Aug 10, 2004Oct 23, 2007Nissan Motor Co., Ltd.Structure for connecting piston to crankshaft
US7318514Aug 19, 2004Jan 15, 2008Nissan Motor Co., Ltd.Low-friction sliding member in transmission, and transmission oil therefor
US7322749May 6, 2005Jan 29, 2008Nissan Motor Co., Ltd.Low-friction sliding mechanism
US7406940May 21, 2004Aug 5, 2008Nissan Motor Co., Ltd.Piston for internal combustion engine
US7427162May 26, 2004Sep 23, 2008Nissan Motor Co., Ltd.Rolling element
US7458585Aug 6, 2004Dec 2, 2008Nissan Motor Co., Ltd.Sliding member and production process thereof
US7496255 *Jun 22, 2004Feb 24, 20093M Innovative Properties CompanyRadiation-transmissive films on glass articles
US7500472Apr 14, 2004Mar 10, 2009Nissan Motor Co., Ltd.Fuel injection valve
US7572200Aug 10, 2004Aug 11, 2009Nissan Motor Co., Ltd.Chain drive system
US7650976Nov 28, 2007Jan 26, 2010Nissan Motor Co., Ltd.Low-friction sliding member in transmission, and transmission oil therefor
US7771821Aug 5, 2004Aug 10, 2010Nissan Motor Co., Ltd.Low-friction sliding member and low-friction sliding mechanism using same
US8096205Jul 23, 2008Jan 17, 2012Nissan Motor Co., Ltd.Gear
US8152377Jul 13, 2010Apr 10, 2012Nissan Motor Co., Ltd.Low-friction sliding mechanism
US8206035Aug 6, 2004Jun 26, 2012Nissan Motor Co., Ltd.Low-friction sliding mechanism, low-friction agent composition and method of friction reduction
US8575076Oct 22, 2008Nov 5, 2013Nissan Motor Co., Ltd.Sliding member and production process thereof
US20030053784 *Sep 17, 2002Mar 20, 2003Labrake Dwayne L.Optical and optoelectronic articles
US20040226677 *Jun 22, 2004Nov 18, 2004Voith Paper Patent GmbhProcess and a fluffer device for treatment of a fiber stock suspension
US20040228578 *Jun 22, 2004Nov 18, 20043M Innovative Properties CompanyRadiation-transmissive films on glass articles
US20050254751 *Dec 4, 2003Nov 17, 2005Toshihiko UshiroOptical fiber having diffractive optical film on end and method for manufacturing same
WO2001066484A1 *Nov 20, 2000Sep 13, 20013M Innovative Properties CoRadiation-transmissive films on glass articles
WO2013098269A1 *Dec 21, 2012Jul 4, 2013Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.Coating of optical waveguides
Classifications
U.S. Classification428/375
International ClassificationC03C25/22, C03C25/10, C23C14/06
Cooperative ClassificationC23C14/0605, C03C25/1075, C03C25/22
European ClassificationC03C25/22, C23C14/06B, C03C25/10P4C