Claims
- 1. A silica glass article which is manufactured by a process comprising the steps of:
(1) irradiating a silica glass article serving as a raw material with electromagnetic waves to generate defects therein; and (2) immersing the thus irradiated silica glass article in an atmosphere comprising a hydrogen gas, thereby providing the resulting silica glass article with a characteristic that is effective for preventing it substantially from increasing its absorption within an ultraviolet region due to ultraviolet ray irradiation.
- 2. The silica glass article according to claim 1, wherein the process further comprises a step of (3) irradiating again the silica glass article that has been subjected to the step (2), with electromagnetic waves while hydrogen molecules remain therein.
- 3. The silica glass article according to claim 2, wherein the process further comprises, after the step (3), a step of (4) reducing the hydrogen molecules that are remaining in the silica glass article to not higher than 1×1016 molecules/cm3 by allowing to stand in the atmosphere or by heating at 80° C. or lower.
- 4. An optical fiber comprising a core and a clad having a refractive index lower than that of the core, the optical fiber having the characteristic that when 108 pulses of KrF excimer laser having a wavelength of 248 nm are applied to the optical fiber, as ultraviolet ray irradiation for an evaluation of ultraviolet resistance, at an output of 10 mJ/cm2 and a pulse frequency of 100 Hz, the optical fiber as measured with a sample of one meter length has a transmittance of not less than 90% of the transmittance measured prior to the irradiation in a wavelength region of ultraviolet ray from 160 nm to 300 nm.
- 5. The optical fiber according to claim 4, which is manufactured by a process comprising the steps of:
(1) irradiating an optical fiber serving as a raw material with electromagnetic waves to generate defects therein; and (2) immersing the thus irradiated optical fiber in an atmosphere comprising a hydrogen gas.
- 6. The optical fiber according to claim 5, wherein the process further comprises a step of (3) irradiating again the optical fiber that has been subjected to the step (2), with electromagnetic waves while the hydrogen molecules that are remaining in the optical fiber is not lower than 1×1016molecules/cm3, so as to impart the characteristic that when 108 pulses of KrF excimer laser having a wavelength of 248 nm are applied to the optical fiber, as ultraviolet ray irradiation for an evaluation of ultraviolet resistance, at an output of 10 mJ/cm2 and a pulse frequency of 100 Hz, the optical fiber as measured with a sample of one meter length has a transmittance of not less than 90% of the transmittance measured prior to the irradiation at a wavelength of 248 nm.
- 7. The optical fiber according to claim 6, wherein the process further comprises, after the step (3), a step of (4) reducing the hydrogen molecules that are remaining in the optical fiber to not higher than 1×1016 molecules/cm3 by allowing to stand in the atmosphere or by heating at 80° C. or lower.
- 8. The optical fiber according to claim 4, wherein the core of the optical fiber comprises high-purity silica glass containing fluorine.
- 9. The optical fiber according to claim 4, wherein the core of the optical fiber comprises high-purity silica glass which contains OH groups in an amount of not less than 100 ppm and which does not contain more than 1 ppm of C1.
- 10. The optical fiber according to claim 8, wherein the high-purity silica glass further contains OH groups in an amount less than 100 ppm.
- 11. The optical fiber according to claim 4, wherein the optical fiber is a bundle fiber formed by bundling a plurality of glass fibers.
- 12. A process for manufacturing a silica glass article comprising the steps of:
(a) introducing hydrogen molecules to the silica glass article to have a hydrogen concentration of not lower than 1×1016 molecules/cm3; and (b) irradiating the hydrogen-introduced silica glass article with an excimer laser or a not more than 100 Gy of γ-ray while the concentration of the hydrogen molecules present in the silica glass article is not lower than 1×1016 molecules/cm3, thereby providing the resulting silica glass article with a characteristic that is effective for preventing it substantially from increasing its absorption within an ultraviolet region due to ultraviolet ray irradiation.
- 13. The process for manufacturing a silica glass article according to claim 12, wherein the step (a) comprises immersing the silica glass article in an atmosphere-comprising a hydrogen gas.
- 14. The process for manufacturing a silica glass article according to claim 13, wherein the step (b) is performed under conditions that the partial pressure of the hydrogen gas is from 0.5 atm to 10 atm and the temperature is not lower than room temperature.
- 15. The process for manufacturing a silica glass article according to claim 12, further comprising, after the step (b),
(c) reducing the hydrogen molecules which are remaining in the silica glass article to not higher than 1×1016 molecules/cm3.
- 16. The process for manufacturing a silica glass article according to claim 15, wherein the step (c) comprises heating the silica glass article at a temperature of from room temperature to 80° C.
- 17. The process for manufacturing a silica glass article according to claim 12,
wherein the silica glass article is an optical fiber, and wherein the step (a) comprises immersing the optical fiber in an atmosphere having a partial pressure of the hydrogen gas of from 0.5 atm to 10 atm and a temperature of from room temperature to a highest upper limit temperature at which coating on the optical fiber is not damaged.
- 18. The process for manufacturing a silica glass article according to claim 12,
wherein the silica glass article is an optical fiber, and wherein the step (a) comprises immersing the optical fiber in an atmosphere having a partial pressure of the hydrogen gas of from 0.5 atm to 10 atm and a temperature of from 80 to 200° C.
- 19. The process for manufacturing a silica glass article according to claim 12, wherein the silica glass article is a bundle fiber formed by bundling a plurality of optical fibers or an optical fiber for a bundle fiber before bundling.
- 20. A silica glass article which is manufactured by a process comprising the steps of:
(a) introducing hydrogen molecules to the silica glass article to have a hydrogen concentration of not lower than 1×1016 molecules/cm3, and (b) irradiating the hydrogen-introduced silica glass article with an excimer laser or a not more than 100 Gy of γ-ray while the concentration of the hydrogen molecules present in the silica glass article is not lower than 1×1016 molecules/cm3, thereby providing the resulting silica glass article with a characteristic that is effective for preventing it substantially from increasing its absorption within an ultraviolet region due to ultraviolet ray irradiation.
- 21. The silica glass article according to claim 20, wherein the process further comprises
(c) reducing the concentration of the hydrogen molecules which are present in the silica glass article to not higher than 1×1016 molecules/cm3 by allowing it to stand in the atmosphere or by heating at a temperature not higher than 80° C.
- 22. An optical fiber comprising a core and a clad having a refractive index lower than that of the core, which is manufactured by a process comprising the steps of:
(a) introducing hydrogen molecules to the core to have a hydrogen concentration of not lower than 1×1016 molecules/cm3; and (b) irradiating the core from the end face thereof with an excimer laser or a not more than 100 Gy of γ-ray while the concentration of the hydrogen molecules present in the core is not lower than 1×1016 molecules/cm3, the optical fiber having the characteristic that when 108 pulses of a KrF excimer laser having a wavelength of 248 nm are applied to the optical fiber at an output of 10 mJ/cm and a pulse frequency of 100 Hz, the optical fiber as measured with a sample of 1 meter length has an ultraviolet ray transmittance of not less than 90% of the ultraviolet ray transmittance measured prior to the irradiation at a wavelength of 248 nm.
- 23. An optical fiber comprising a core and a clad having a refractive index lower than that of the core, which is manufactured by a process comprising the steps of:
(a) introducing hydrogen molecules to the core to have a hydrogen concentration of not lower than 1×1016 molecules/cm3; (b) irradiating the core from the end face thereof with an excimer laser or a not more than 100 Gy of γ-ray while the concentration of the hydrogen molecules present in the core is not lower than 1×1016 molecules/cm3; and (c) reducing the concentration of the hydrogen molecules which are present in the core to not higher than 1×1016 molecules/cm3 by allowing it to stand in the atmosphere or by heating at a temperature not higher than 80° C., the optical fiber having the characteristic that when 108 pulses of a KrF excimer laser having a wavelength of 248 nm are applied to the optical fiber at an output of 10 mJ/cm2 and a pulse frequency of 100 Hz, the optical fiber as measured with a sample of 1 meter length has an ultraviolet ray transmittance of not less than 90% of the ultraviolet ray transmittance measured prior to the irradiation at a wavelength of 248 nm.
- 24. The optical fiber according to claim 22, wherein the core of the optical fiber comprises high purity silica glass containing fluorine.
- 25. The optical fiber according to claim 23, wherein the core of the optical fiber comprises high purity silica glass containing fluorine.
- 26. The optical fiber according to claim 22, wherein the core of the optical fiber does not contain more than 1 ppm of C1.
- 27. The optical fiber according to claim 23, wherein the core of the optical fiber does not contain more than 1 ppm of C1.
- 28. The optical fiber according to claim 22, wherein the optical fiber is a bundle fiber formed by bundling a plurality of glass fibers.
- 29. The optical fiber according to claim 23, wherein the optical fiber is a bundle fiber formed by bundling a plurality of glass fibers.
- 30. The silica glass article having defects generated when its precursor is irradiated with a photon energy of not less than 3.5 eV, hydrogen atoms being bonded to the defects,
wherein the silica glass article has a characteristic that it is substantially prevented from increasing its absorption within an ultraviolet region after irradiation by a deuterium lamp for 48 hours.
- 31. An optical fiber comprising silica glass and having defects generated when its precursor is irradiated with a photon energy of not less than 3.5 eV, hydrogen atoms being bonded to the defects,
wherein the optical fiber has the characteristic that when 108 pulses of a KrF excimer laser having a wavelength of 248 nm are applied to the optical fiber at an output of 10 mJ/cm2 and a pulse frequency of 100 Hz, the optical fiber as measured with a sample of 1 meter length has an ultraviolet ray transmittance of not less than 90% of the ultraviolet ray transmittance measured prior to the irradiation at a wavelength of 248 nm.
- 32. An optical fiber comprising silica glass and having defects generated when its precursor is irradiated with a photon energy of not less than 3.5 eV, hydrogen atoms being bonded to the defects,
wherein the optical fiber has the characteristic that when 108 pulses of a KrF excimer laser having a wavelength of 248 nm are applied to the optical fiber at an output of 10 mJ/cm2 and a pulse frequency of 100 Hz, the optical fiber as measured with a sample of 1 meter length has an ultraviolet ray transmittance of not less than 90% of the ultraviolet ray transmittance measured prior to the irradiation in a wavelength region of from 160 nm to 300 nm.
- 33. An optical fiber comprising a core comprising a fluorine and silica glass, the silica glass having defects, hydrogen atoms being bonded to the defects, wherein the optical fiber has the characteristic that when 108 pulses of a KrF excimer laser having a wavelength of 248 nm are applied to the optical fiber at an output of 10 mJ/cm2 and a pulse frequency of 100 Hz, the optical fiber as measured with a sample of 1 meter length has an ultraviolet ray transmittance of not less than 90% of the ultraviolet ray transmittance measured prior to the irradiation at a wavelength of 248 nm.
- 34. The optical fiber according to claim 33, wherein the core of the optical fiber contains OH groups in an amount of not more than 100 ppm, and the number of the hydrogen molecules not bonded to the silica glass is not more than 1×1016 molecules/cm3.
- 35. An optical fiber comprising silica glass and having defects generated when its precursor is irradiated with a photon energy of not less than 3.5 eV, hydrogen atoms being bonded to the defects, the defects having a bonding with hydrogen, the bonding being formed upon irradiation with a predetermined dose of electromagnetic waves having a wavelength not more than 248 nm,
wherein the optical fiber has the characteristic that when 108 pulses of a KrF excimer laser having a wavelength of 248 nm are applied to the optical fiber at an output of 10 mJ/cm2 and a pulse frequency of 100 Hz, the optical fiber as measured with a sample of 1 meter length has an ultraviolet ray transmittance of not less than 90% of the ultraviolet ray transmittance measured prior to the irradiation at a wavelength of 248 nm.
Priority Claims (3)
Number |
Date |
Country |
Kind |
P.HEI.9-127285 |
May 1997 |
JP |
|
P.HEI.10-86709 |
Mar 1998 |
JP |
|
P.HEI.11-5581 |
Jan 1999 |
JP |
|
CROSS-REFERENCE
[0001] This application is a Continuation In Part of application Ser. No. 09/080,247 for which the issue fee was paid on Jul. 30, 1999.
Divisions (1)
|
Number |
Date |
Country |
Parent |
09369425 |
Aug 1999 |
US |
Child |
09998328 |
Dec 2001 |
US |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
09080247 |
May 1998 |
US |
Child |
09369425 |
Aug 1999 |
US |