Method to reduce light propagation losses in optical glasses and optical waveguide fabricated by same

• US 5,235,662 A
• Filed: 01/02/1992
• Issued: 08/10/1993
• Est. Priority Date: 01/02/1992
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Prospero, Sebastian F., Romach, Mark M., Prince, Eric T.
• Primary Examiner(s): Healy, Brian
• Application Number:
  US07/815,779
• Time in Patent Office: 586 Days
• Field of Search: 385/127, 385/128, 385/129, 385/130, 385/131, 385/132, 385/14, 385/141-147, 65/2, 65/3.11, 65/12, 65/17, 65/41, 65/66, 65/69, 501/11, 501/27, 501/37, 501/49, 501/53, 501/63, 501/94, 501/95, 501/100, 501/127, 501/133, 501/153, 501/154, 501/900, 437/51
• US Class Current: 385/129
• CPC Class Codes: C03B 37/15 with heat application, e.g. for making optical fibres fusion-splicing of light guides G02B6/255; treatment of light guides to shape optical elements G02B6/2835, G02B6/2856
• CPC Class Codes: C03C 23/007 by thermal treatment
• CPC Class Codes: G02B 2006/12038 Glass (SiO2 based materials)
• CPC Class Codes: G02B 2006/12159 Interferometer
• CPC Class Codes: G02B 2006/12171 using a laser beam
• CPC Class Codes: G02B 6/10 of the optical waveguide type G02B6/02, G02B6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F1/00; transferring the modulation of modulated light G02F2/00; optical logic elements G02F3/00; optical analogue/digital converters G02F7/00
• CPC Class Codes: Y10S 501/90 Optical glass, e.g. silent on refractive index and/or ABBE number

Abstract

The present invention provides a method of annealing optical glass layers, said method comprising the step of heating glass layers having an area greater than 0.01 cm² to a temperature of between about 350 deg. C. and 1000 deg. C. in less than 10 minutes. The upper limit of the glass area that can be treated is limited only by the size of the quartz chamber. Current state-of-the-art chambers can accomodate glass areas of about 0.01 cm² to about 324 cm². According to another aspect of the invention, there is also provided an optical waveguide glass layer, treated according to the method of this invention, disposed on an integrated optical device.

Claims

1. A method of annealing optical glass layers, said method comprising the step of heating glass layers having an area of about >

0.01 cm² -324 cm² to a temperature of between about 350°

C. and 1000°

C. in less than 10 minutes.

2. The method of claim 1 wherein the glass layer reaches a temperature of between about 500°

C. to about 1000°

C. in 0.5 to 2 minutes.

3. The method of claim 1 wherein the glass layer reaches a temperature of between about 600°

C. to about 900°

C. in about 2 seconds to 1 minute.

4. The method of claim 1 or 2 wherein the glass layer is selected from the group consisting of a baria-borosilicate glass and a borosilicate crown.

5. The method of claim 1 wherein the glass layer comprises silicon oxide, aluminum oxide, barium oxide and boron oxide as the principal components.

6. The method of claim 1 wherein the glass layer comprises silicon oxide, boron oxide, sodium oxide, and potassium oxide as the principal components.

7. The method of claim 1 wherein, after heating, the temperature of the glass layer drops to a temperature of between 450°

C. and 150°

C. in about 25 seconds to 3 minutes.

8. An optical waveguide having a light propagation loss of about 0.01 dB/cm to about 1 dB/cm and prepared by heating glass layers having an area of about 0.01 cm² to about 324 cm² to a temperature of between about 350°

C. and 1000°

C. in less than 10 minutes.

9. The optical waveguide of claim 8, coated on an optical device.

10. The optical waveguide of claim 8, disposed on an integrated optical device.

11. The optical waveguide of claim 9 or 10, wherein the optical device is selected from the group consisting of an integrated optical read/write head, a beam deflector, an interferometer, a waveguide modulator, a page scanner, and a radio frequency spectrum analyzer.