# US 5,345,528 A · Method for enhancing the pullout strength of polymer-coated optical fiber

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- Number: US 5,345,528 A
- Document ID: US5345528A
- Status: Granted
- Kind: A
- Application number: 08/098,972
- Filed: 1993-07-28
- Granted: 1994-09-06
- Earliest claimed: 1993-07-28
- Assignees: AT&T Bell Laboratories
- Inventors: Howard Edan Katz; Valerie J. Kuck; Marcia L. Schilling
- Web page: https://patentgrep.com/patent/US5345528A

## CPC

- G02B 6/03694: {Multiple layers differing in properties other than the refractive index, e.g. attenuation, diffusion, stress properties}
- C03C 25/12: General methods of coating; Devices therefor
- G02B 6/02395: {Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture (G02B6/02052, G02B6/02057, G02B6/024, G02B6/032, G02B6/105, G02B6/14 take precedence; coating on fibre gratings G02B6/02104; multilayer core or cladding G02B6/036; reinforcing splice joints G02B6/2558; optical cables, i.e. comprising protective structures external to the protective coating such as a jacket or plural coated optical fibres G02B6/44; coating of glass to obtain optical fibres C03C25/104)}
- G02B 6/03638: {having 3 layers only}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS

## Abstract

Applicants have discovered that by heating cured polymer-coated fiber at temperatures of 100.degree. C. or more, they can enhance the fiber pullout strength by 25% or more. This postcure heating can advantageously be done off-line by placing loosely wound fiber in a heated oven. Alternatively the postcure heating can be done on-line by reel-to-reel passage of the fiber through a heated furnace. Preferred temperatures are in the range 100.degree. C.-300.degree. C.

## Claims

### Claim 1

A method for enhancing the pullout strength of polymer-coated optical fiber comprising the steps of:
providing a cured, polymer-coated optical fiber; and
heating said fiber at a temperature in the range 100.degree. C. to 300.degree. C. for a time sufficient to increase the pullout strength by at least 25%.

### Claim 2 (depends on 1)

The method of claim 1 wherein said fiber is heated off line in a heated oven.

### Claim 3 (depends on 1)

The method of claim 1 wherein said fiber is heated on-line by passage through a heated furnace.

### Claim 4 (depends on 1)

The method of claim 1 wherein said polymer-coated optical fiber is coated with a polymer from the group consisting of hydrocarbon polymers, polyethers, polycarbonates, polyesters and silicones.

### Claim 5 (depends on 1)

The method of claim 1 wherein said polymer-coated optical fiber is coated with a polymer terminated by urethane-acrylates.

### Claim 6 (depends on 1)

The method of claim 1 wherein said fiber comprises silica.