US5732170A
Expired / Lapsed
US
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Optical fiber filter
Assignee: Fujikura Ltd
•
Filing: 1996-10-21
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Granted: 1998-03-24
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Expires: 2016-10-21
Abstract
Abstract The present invention relates to an optical fiber filter provided with a portion which selectively reflects or transmits light of a specific wavelength, this portion comprised of a multimode optical fiber in which the refractive index of the core changes periodically along the longitudinal direction thereof. Furthermore, this multimode optical fiber has an input end and an output end, with at least the input end of the multimode optical fiber being connected to a single mode optical fiber. As a result of forming an optical fiber filter in this way, it is possible to realize an optical fiber filter that exhibits no transmission loss at wavelengths other than the center wavelength.
Inventors
- 👤 Satoshi Okude
- 👤 Tetsuya Sakai
- 👤 Akira Wada
- 👤 Ryozo Yamauchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:52
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29304; G02B6/29316; G02B6/29317; G02B6/02; G02B6/02057; G02B6/02076; G02B6/0208; G02B6/021; G02B6/02209; G02B6/255; G02B6/2551; G02B6/2552; G02B6/29379; G02B6/2938; G02B6/29331; G02B6/29332; G02B6/36; G02B6/38; G02B6/3807; G02B6/3833; G02B6/3845
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
83 words
An optical fiber filter having a portion which selectively reflects or transmits light of a specific wavelength, wherein: the portion for selectively reflecting or transmitting light of a specific wavelength is comprised of a multimode optical fiber in which the refractive index of the core changes periodically along the longitudinal direction thereof; the multimode optical fiber having an input end and an output end, wherein at least the input end of the multimode optical fiber is connected to a single mode optical fiber.
Claim 2
Dependent Claim
83 words
An optical fiber filter having a portion which selectively reflects or transmits light of a specific wavelength, wherein: the portion for selectively reflecting or transmitting light of a specific wavelength is comprised of a multimode optical fiber in which the refractive index of the core changes periodically along the longitudinal direction thereof; the multimode optical fiber having an input end and an output end, wherein at least the input end of the multimode optical fiber is connected to a single mode optical fiber.
Claim 3
Dependent Claim
89 words
An optical fiber filter having a portion for selectively reflecting or transmitting light of a specific wavelength, wherein: the portion for selectively reflecting or transmitting light of a specific wavelength comprises a multimode optical fiber in which the refractive index of the core changes periodically along the longitudinal direction thereof; the multimode optical fiber having an input end and an output end, wherein at least the input end of the multimode optical fiber is connected to an external single mode optical fiber or an external single mode optical waveguide.
Claim 4
Dependent Claim
89 words
An optical fiber filter having a portion for selectively reflecting or transmitting light of a specific wavelength, wherein: the portion for selectively reflecting or transmitting light of a specific wavelength comprises a multimode optical fiber in which the refractive index of the core changes periodically along the longitudinal direction thereof; the multimode optical fiber having an input end and an output end, wherein at least the input end of the multimode optical fiber is connected to an external single mode optical fiber or an external single mode optical waveguide.
Claim 5
Dependent Claim
57 words
An optical fiber filter according to claim 1, wherein the mode field diameter of the LP01 mode of the light propagating in the multimode optical fiber, and the mode field diameter of the single mode optical fiber, approach each other in size at least the connection between the multimode optical fiber and the single mode optical fiber.
Claim 6
Dependent Claim
73 words
An optical fiber filter according to claim 2, wherein the mode field diameter of the LP01 mode of the light propagating in the multimode optical fiber, and the mode field diameter of the external single mode optical fiber or the external single mode optical waveguide, approach each other in size at least the connection between the multimode optical fiber and the external single mode optical fiber or the external single mode optical waveguide.
Claim 7
Dependent Claim
40 words
An optical fiber filter according to claim 3, wherein the connection loss at the connection between the multimode optical fiber and the single mode optical fiber is 1 dB or less at the operation wavelengths of the optical fiber filter.
Claim 8
Dependent Claim
47 words
An optical fiber filter according to claim 4, wherein the connection loss at the connection between the multimode optical fiber and the external single mode optical fiber or external single mode optical waveguide is 1 dB or less at the operation wavelengths of the optical fiber filter.
Claim 9
Dependent Claim
36 words
An optical fiber filter according to claim 3, wherein the diameter of the core of the single mode optical fiber at the connection between the multimode optical fiber and the single mode optical fiber is enlarged.
Claim 10
Dependent Claim
37 words
An optical fiber filter according to claim 4, wherein the diameter of the core of the external single mode optical fiber or the core of the external single mode optical waveguide is enlarged at the connection therebetween.
Claim 11
Dependent Claim
38 words
An optical fiber filter according to claim 3, wherein the diameter of the core in the multimode optical fiber and the diameter of the core of the single mode optical fiber are both enlarged at the connection therebetween.
Claim 12
Dependent Claim
46 words
An optical fiber filter according to claim 4, wherein the diameter of the core in the multimode optical fiber and the diameter of the core of the external single mode optical fiber or the external single mode optical waveguide are both enlarged at the connection therebetween.
Claim 13
Dependent Claim
49 words
An optical fiber filter according to claim 1, wherein the ratio of the mode field diameter of the LP01 mode of light propagating in the multimode optical fiber with respect to the mode field diameter of the single mode optical fiber is in the range of 1.0 to 1.5.
Claim 14
Dependent Claim
57 words
An optical fiber filter according to claim 2, wherein the ratio of the mode field diameter of the LP01 mode of light propagating in the multimode optical fiber with respect to the mode field diameter of the external single mode optical fiber or the external single mode optical waveguide is in the range of 1.0 to 1.5.
Claim 15
Dependent Claim
50 words
An optical fiber filter according to claim 1, wherein germanium is doped to the core of the multimode optical fiber, and periodical light is irradiated along the longitudinal direction thereof to form periodical changes in the refractive index of the core along the longitudinal direction of the multimode optical fiber.
Claim 16
Dependent Claim
50 words
An optical fiber filter according to claim 2, wherein germanium is doped to the core of the multimode optical fiber, and periodical light is irradiated along the longitudinal direction thereof to form periodical changes in the refractive index of the core along the longitudinal direction of the multimode optical fiber.
Claim 17
Dependent Claim
19 words
An optical fiber filter according to claim 1, wherein the multimode optical fiber is a graded index optical fiber.
Claim 18
Dependent Claim
19 words
An optical fiber filter according to claim 2, wherein the multimode optical fiber is a graded index optical fiber.
Claim 19
Dependent Claim
22 words
An optical fiber filter according to claim 1, wherein the multimode optical fiber and the single mode optical fiber are fusion spliced.
Claim 20
Dependent Claim
30 words
An optical fiber filter according to claim 2, wherein the multimode optical fiber and the external single mode optical fiber or the external single mode optical waveguide are fusion spliced.
Claim 21
Dependent Claim
24 words
An optical fiber filter according to claim 1, wherein the multimode optical fiber is housed in a plug housing of an optical fiber connector.
Claim 22
Dependent Claim
24 words
An optical fiber filter according to claim 2, wherein the multimode optical fiber is housed in a plug housing of an optical fiber connector.
Claim 23
Dependent Claim
24 words
An optical fiber filter according to claim 1, wherein the multimode optical fiber is housed inside an adaptor housing of an optical fiber connector.
Claim 24
Dependent Claim
24 words
An optical fiber filter according to claim 2, wherein the multimode optical fiber is housed inside an adaptor housing of an optical fiber connector.
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