Claims
- 1. A method for adjusting a photosensitive optical waveguide having an optical path length to a stabilized desired optical path length, the method comprising the steps of:
a) changing the optical path length of the photosensitive optical waveguide by exposing at least a first portion of the waveguide to actinic radiation and creating an induced refractive index change in the exposed first portion; b) subjecting the waveguide to an annealing cycle that stabilizes the waveguide; c) after the step of stabilizing the waveguide, adjusting the optical path length by subjecting at least a selected part of the exposed first portion of the waveguide to a localized heating sufficient to change the refractive index at the selected part until the desired optical path length is achieved.
- 2. The method of claim 1, wherein the photosensitive waveguide comprises a glass waveguide which has been hydrogen loaded.
- 3. The method of claim 1, further comprising the step of writing an optical grating in a second portion of the waveguide.
- 4. The method of claim 3, wherein the step of writing an optical grating occurs before the step of stabilizing the waveguide.
- 5. The method of claim 1, wherein the step of stabilizing the waveguide comprises heating the waveguide to a first temperature to stabilize the device and the step of adjusting the optical path length includes heating at least a part of the exposed first portion to a second temperature wherein the second temperature is greater than the first temperature.
- 6. The method of claim 1, wherein the step of stabilizing the waveguide comprises heating the waveguide to a first temperature to stabilize the device and the step of adjusting the optical path length includes heating at least a part of the exposed first portion until the desired optical path length is achieved.
- 7. The method of claim 1, wherein the waveguide is a first leg of an interferometric device having at least a second leg and the step of adjusting the induced index change comprises adjusting the optical path length difference between the first leg and the second leg.
- 8. The method of claim 1, wherein the step of adjusting the optical path length further comprises contemporaneously monitoring the optical path length of the waveguide during the localized heating exposure and terminating the exposure when the desired optical path length is reached.
- 9. The method of claim 1, wherein the step of adjusting the optical path length by subjecting at least a part of the exposed first portion of the waveguide includes heating the at least part of the exposed first portion using a CO2 laser.
- 10. A method for making a stabilized photosensitive optical waveguide having a desired optical path length, the method comprising the steps of:
a) providing a photosensitive waveguide; b) changing the optical path length of the waveguide by exposing at least a first portion of the waveguide to actinic radiation and creating an induced refractive index change on the exposed portion; c) stabilizing the waveguide via an annealing cycle; d) after the step of stabilizing the waveguide, reducing the induced index change on the exposed first portion to achieve the desired stable optical path length by locally heating at least a part of the exposed first portion of the waveguide.
- 11. The method of claim 10 wherein the step of providing a photosensitive waveguide comprises providing a glassy waveguide and hydrogen loading the glassy waveguide.
- 12. The method of claim 10, further comprising the step of writing an optical grating in a second portion of the waveguide before annealing the waveguide.
- 13. The method of claim 10 wherein the step of annealing the waveguide comprises heating the waveguide at a temperature greater than the maximum operating temperature of the waveguide and reducing the induced index change includes heating the at least a part of the exposed first portion to a temperature greater than the maximum operating temperature of the waveguide.
- 14. The method of claim 10, wherein the step of reducing the induced index change includes irradiating a discrete section of the exposed first portion of the waveguide using a CO2 laser.
- 15. A method for tuning and balancing an optical waveguide interferometric device, the method comprising the steps of:
a) providing a waveguide interferometric device having at least a first optical path and a second optical path; b) exposing at least a first portion of the first path to a blanket exposure of actinic radiation; c) annealing the first optical path to stabilize the device; d) adjusting the optical path length of the first optical path by locally heating at least a part of the first portion of the first optical path until the desired optical path length is achieved.
- 16. The method of claim 15, wherein the step of adjusting the optical path length comprises adjusting the relative phases between the first and the second optical path.
- 17. The method of claim 15, further comprising applying steps b-d to the second optical path.
- 18. The method of claim 15, further comprising the step of writing an optical grating in at least one of the optical paths.
- 19. An interferometer manufactured in accordance with the method of claim 15.
- 20. The interferometer of claim 19, wherein the interferometer is selected from the group consisting of Michelson, Mach-Zehnder, Sagnac, and Fabry-Perot interferometers.
- 21. The interferometer of claim 20, wherein the waveguide is selected from a group consisting of an optical fiber and a planar waveguide.
- 22. An optical waveguide interferometric device having a first and a second output beams, the interferometric device comprising:
a) at least two interferometer legs at least one first leg having a photosensitive waveguide; b) an optical recombination point optically coupled to the at least one interferometer leg; and c) a portion of the at least one first leg having a refractive index perturbation larger by 10−5 than surrounding waveguide material; d) wherein the index perturbation is stabilized to the extent that the optical path length of the first leg only changes by an amount that causes a phase difference between the first and second output interferometer beams at the optical recombination point of less than about 5° at 25° C. after the temperature of the interferometric device has been cycled up to 80° C. and returned back to 25° C.
- 23. The optical waveguide interferometric device of claim 22, wherein the at least two interferometer legs comprise two legs in an arrayed waveguide configuration.
- 24. The optical waveguide interferometric device of claim 22, further including at least one Bragg grating in the at least two interferometer legs.
- 25. The interferometer of claim 22, wherein the interferometer is selected from the group consisting of Michelson, Mach-Zehnder, Sagnac, and Fabry-Perot interferometers.
RELATED PUBLICATIONS
[0001] The present application relates to and claims priority from co-pending, commonly assigned, provisional application entitled Method to Stabilize and Adjust the Optical Path Length of Waveguide Devices, filed on Jun. 14, 2000, U. S. Ser. No. 60/211,521, which is hereby incorporated by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60211521 |
Jun 2000 |
US |