Patent EP0074789A2 successfully refreshed from Google Patents.
EP0074789A2
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EP
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Fiber optic directional coupler
Assignee: Leland Stanford Junior University
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Filing: 1982-09-08
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Granted: —
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Expires: 2002-09-08
Abstract
Abstract A fiber optic directional coupler (10) comprises a pair of bases (16), with respective longitudinal, arcuate grooves (13) formed therein on confronting faces (14) thereof, for mounting a pair of optical fibers (12) in close proximity. A portion of the cladding is removed from each of the fibers (12) to form planar facing surfaces (18) which permits the spacing between the fiber cores to be within a predetermined critical zone (34) so that guided modes of the fibers (12) interact, through their evanescent fields, to cause light to be transferred by evanescent field coupling between the fibers (12). The coupler (10) is "tuned" to a desired coupling efficiency by offsetting the planar facing surfaces (18) to increase the spacing between the fiber cores. A method of manufacture of the coupler includes procedures which permit the coupler halves to be made symmetrical. The method also permits couplers (10) having given coupling characteristics to be reproduced.
Inventors
- 👤 Herbert John Shaw
- 👤 Ralph A. Bergh
- 👤 Herve C. Lefevre
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 03:16
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2821; G02B6/2826; G01; G01N; G01N37/00; G02B6/283; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
95 words
A method of lapping the cladding of a fiber optic strand (12) to a predetermined distance from the core of said strand, characterized by: lapping said strand (12); illuminating (120) said strand to propogate light therethrough; coating the lapped area (18) with a substance (124) whose index of refraction approximates that of said strand (12); and determining (122) whether the portion of strand illumination which escapes at the lapped portion (18) of said strand (12) has reached a predetermined value to determine whether said lapping has reached the critical zone (34) of said strand (12).
Claim 2
Independent Claim
95 words
A method of lapping the cladding of a fiber optic strand (12) to a predetermined distance from the core of said strand, characterized by: lapping said strand (12); illuminating (120) said strand to propogate light therethrough; coating the lapped area (18) with a substance (124) whose index of refraction approximates that of said strand (12); and determining (122) whether the portion of strand illumination which escapes at the lapped portion (18) of said strand (12) has reached a predetermined value to determine whether said lapping has reached the critical zone (34) of said strand (12).
Claim 3
Dependent Claim
31 words
A method, as defined in Claim 1, further characterized by: mounting said strand in a groove (13) in a block (16); and lapping said strand (12) and said block (16) together.
Claim 4
Dependent Claim
30 words
A method, as defined in Claim 1 or Claim 2, further characterized by: said determining step includes measuring the strand illumination which has not escaped at the lapped portion (18).
Claim 5
Independent Claim
39 words
A method, as defined in any of Claims 1, 2, or 3, further characterized by: measuring the width of said lapped portion (18) of said strand (12) to determine the depth of said core beneath said lapped portion (18).
Claim 6
Independent Claim
60 words
A method, as defined in any of Claims 1, 2, 3, or 4, further characterized by: - superimposing said lapped portion (18) over the lapped portion (18) of a second lapped fiber optic strand (12b); and mutually translating said lapped portions (18) of said strand (12) and said second strand (12b) to adjust the light coupling efficiency of said strands.
Claim 7
Dependent Claim
20 words
A method, as defined in Claim 5, wherein said strand (12) and said second strand (12b) are translated to over-couple.
Claim 8
Dependent Claim
24 words
A method, as defined in Claim 6, wherein said strand (12) and said second strand (12b) couple light through an over-coupled evanescent interaction zone.
Claim 9
Independent Claim
58 words
A method, as defined in any of Claims 1, 2, 3, 4, or 5, additionally characterized by: measuring the portion of strand illumination which escapes at the lapped portion (18) without said coating (124); and determining the extinction ratio as the ratio between the light which escapes from said lapped portion (18) with and without said coating (124).
Claim 10
Dependent Claim
45 words
A method, as defined in Claim 8, additionally characterized by: determining the coupling efficiency which will result from superimposing said lapped portion (18) on an identical fiber lapped portion having the same extinction ratio; and controlling said lapping step in accordance with said coupling efficiency.
Claim 11
Independent Claim
37 words
A method, as defined in any of Claims 1, 2, 3, 4, or 5, additionally characterized by: changing the termperature of said coating (124) to adjust its index of refraction to match that of the strand (12).
Claim 12
Dependent Claim
42 words
A fiber optic coupler, comprising: a first optical fiber (12a); a second optical fiber (12b) juxtaposed to said - first fiber (12a); and an interaction zone (32) at the juxtaposition of said fibers which causes over-coupled evanescent light coupling between said fibers.
Claim 13
Dependent Claim
42 words
A fiber optic coupler, comprising: a first optical fiber (12a); a second optical fiber (12b) juxtaposed to said - first fiber (12a); and an interaction zone (32) at the juxtaposition of said fibers which causes over-coupled evanescent light coupling between said fibers.
References Cited (Backward Citations)
No citation records indexed.
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