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US5375181A
Expired / Lapsed
US
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Temperature compensated fiber fabry-perot filters
Assignee: Luna Innovations Inc
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Filing: 1993-10-13
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Granted: 1994-12-20
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Expires: 2013-10-13
Abstract
Abstract Temperature compensated Fiber Fabry Perot filters are provided. These filters display minimal wavelength drift over a wide range of temperatures. The temperature coefficients of the filters can be adjusted after construction. These FFPs are particularly useful in applications in which filter size is a constraint. The disclosed filter designs can be employed for minaturized filters which retain thermal and optical stability over a wide range of temperatures. In particular, low-loss thermally stable FFPs suitable for use in circuit board applications are provided.
Inventors
- 👤 Calvin M. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:57
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29379; G02B6/29395; G02B6/241; G02B6/29346; G02B6/29358; G02B6/29359; G02B6/29398; G02B6/36; G02B6/38; G02B6/3807; G02B6/3869; G02B6/3873; G02B6/3882; G02B6/3833; G02B6/3845
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
226 words
A temperature compensated fiber Fabry-Perot filter which comprises: a fiber ferrule assembly having an optical resonance cavity therein which comprises a first and a second ferrule element each of which has a substantially axial bore therethrough for receiving an optical fiber and a mirror transverse to said axial bore and each of which ferrules has an internal end said ferrules positioned with respect to each other such that the internal ends of said ferrules are opposed and an optical resonance cavity is formed between opposing reflective surfaces of said mirrors; sleeve means positioned around the circumference of each of said ferrules; a support means for holding said ferrules and said sleeves such that the length of said optical cavity can be changed which comprises a first and a second ferrule holder each of which holders has an internal end and a piezoelectric transducer means for electronically changing the length of said optical cavity interposed between the internal ends of said first and second holders such that the distance between said holders can be changed whereby the optical cavity length is changed; each of said holders having an essentially cylindrical passageway therethrough for receiving said ferrule and sleeve, and a plurality of adjustable means along the length of said passageway for contacting said sleeve which in turn contacts said ferrule thereby securing said ferrule within said passageway.
Claim 2
Dependent Claim
226 words
A temperature compensated fiber Fabry-Perot filter which comprises: a fiber ferrule assembly having an optical resonance cavity therein which comprises a first and a second ferrule element each of which has a substantially axial bore therethrough for receiving an optical fiber and a mirror transverse to said axial bore and each of which ferrules has an internal end said ferrules positioned with respect to each other such that the internal ends of said ferrules are opposed and an optical resonance cavity is formed between opposing reflective surfaces of said mirrors; sleeve means positioned around the circumference of each of said ferrules; a support means for holding said ferrules and said sleeves such that the length of said optical cavity can be changed which comprises a first and a second ferrule holder each of which holders has an internal end and a piezoelectric transducer means for electronically changing the length of said optical cavity interposed between the internal ends of said first and second holders such that the distance between said holders can be changed whereby the optical cavity length is changed; each of said holders having an essentially cylindrical passageway therethrough for receiving said ferrule and sleeve, and a plurality of adjustable means along the length of said passageway for contacting said sleeve which in turn contacts said ferrule thereby securing said ferrule within said passageway.
Claim 3
Dependent Claim
62 words
The filter of claim 1 wherein the optical fiber of said optical cavity comprises a fiber gap and said support means functions to hold the optical fibers of said ferrules in axial alignment such that the length of said optical cavity can be changed by application of an appropriate voltage to said piezoelectric transducer means without substantial change to said fiber alignment.
Claim 4
Dependent Claim
47 words
The filter of claim 2 wherein said piezoelectric transducer means comprises a piezoelectric transducer element interposed between said ferrule holders such that selective application of a voltage to said transducer changes the optical cavity length without substantially changing the alignment of the optical fibers of said ferrules.
Claim 5
Dependent Claim
45 words
The filter of claim 3 wherein said piezoelectric transducer element has a first and a second end and a longitudinal axis along which it expands between said ends and comprises a cylindrical passageway along said expanding axis for receiving the internal ends of said ferrules.
Claim 6
Dependent Claim
58 words
The filter of claim 4 wherein the first end of said piezoelectric transducer element is rigidly attached to the internal end of said first holder and said second end of said piezoelectric transducer element is rigidly attached to the internal end of said second ferrule holder whereby said piezoelectric transducer element is interposed between said ferrule holder means.
Claim 7
Dependent Claim
30 words
The filter of claim 5 wherein the ends of said holder are attached to the ends of said transducer element employing a controlled thickness of a positive temperature coefficient adhesive.
Claim 8
Dependent Claim
39 words
The filter of claim 6 wherein said adhesive is an epoxy and said epoxy thickness is controlled by insertion of a non-deformable gauge wire between the transducer end and the holder end to which it is to be attached.
Claim 9
Dependent Claim
60 words
The filter of claim 6 wherein the internal end of each of said holders comprises a flange extending outwardly from the body of the holder around the circumference of the passageway such that adhesive used in the connection between the ends of the holder and the transducer does not contact the ferrules or enter the optical cavity of the filter.
Claim 10
Dependent Claim
43 words
The filter of claim 6 wherein said sleeve substantially extends the length of said ferrule within the passageway of said holder such that the adjustable means for securing the ferrule in said holder passageway contact said sleeve and thereby secure said ferrule therein.
Claim 11
Dependent Claim
59 words
The filter of claim 9 wherein said essentially cylindrical passageway in said holder comprises a keyway along its axial length and said sleeve comprises a slot for receiving said keyway along its axial length such that when said sleeve is positioned in said passageway and said keyway is aligned within said slot the sleeve cannot rotate within said passageway.
Claim 12
Dependent Claim
31 words
The filter of claim 6 wherein said sleeve is made of a material which has a positive temperature coefficient larger than that of the material of which the holder is made.
Claim 13
Dependent Claim
11 words
The filter of claim 11 wherein said sleeve is phosphor bronze.
Claim 14
Dependent Claim
25 words
The filter of claim 12 wherein the ferrule holders and the means therein for securing the ferrule within the holder are made of stainless steel.
Claim 15
Dependent Claim
31 words
The filter of claim 6 wherein said means for securing said ferrule within said holder also function as an adjustable means for changing the cavity length temperature coefficient of said filter.
Claim 16
Dependent Claim
33 words
The filter of claim 14 wherein said means for securing said ferrule within said holder also function as an adjustable means for changing the axial alignment of said optical fibers in said filter.
Claim 17
Dependent Claim
64 words
The filter of claim 15 wherein said means of securing said ferrules within said holder comprise a plurality of screws which extend through the body of said holder into the passageway of said holder and which can be independently adjusted by turning to extend through the body of said holder into said passageway rigidly contacting said sleeve which in turn rigidly contacts said ferrule.
Claim 18
Dependent Claim
27 words
The filter of claim 16 wherein said independently adjustable screws are positioned along the length of said passageway and extend into said passageway from the same direction.
Claim 19
Dependent Claim
80 words
The filter of claim 15 wherein said means for securing said ferrules in said holder comprise one or more sets of screws wherein each set of screws is positioned in said holder such that they can extend upon turning into said passageway at the same position along the length of the passageway axis and are equiangularly distributed around the circumference of said passageway and wherein each set of screws enter the passageway at a different position along said passageway axis.
Claim 20
Dependent Claim
13 words
The filter of claim 18 wherein each set of screws contains four screws.
Claim 21
Dependent Claim
11 words
The filter of claim 18 wherein said screws have flat ends.
Claim 22
Dependent Claim
71 words
The filter of claim 15 wherein said means for securing said ferrules in said holder comprise one set of screws equiangularly distributed around the circumference of said passageway which function to change the alignment of said filter and a plurality of screws along the length of said passageway which extend into said passageway from the same direction which function to allow adjustment of the cavity length temperature coefficient of said filter.
Claim 23
Dependent Claim
29 words
The filter of claim 21 in which said set of screws contains four screws and wherein two or more additional screws are positioned along the length of said passageway.
Claim 24
Dependent Claim
29 words
The filter of claim 22 wherein the screws of said set of screws have flat ends and said additional screws along the length of said passageway have cupped ends.
Claim 25
Dependent Claim
17 words
The filter of claim 1 wherein said mirrors are formed by depositing layers of Si/SiO 2 .
Claim 26
Dependent Claim
19 words
The filter of claim 1 wherein said mirrors are formed by depositing layers of TiO 2 /SiO 2 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-12-19 | 1998-06-20 | 1998-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-19 | 2002-06-20 | 2002-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-19 | 2006-06-20 | 2006-12-20 | $7700.00 | Window Closed / Lapsed |