Patent US5138675A successfully refreshed from Google Patents.
US5138675A
Expired / Lapsed
US
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Mode scrambler as an optical isolator for higher-coherence lasers in multi-mode fiber plants
Assignee: Hewlett Packard Development Co LP
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Filing: 1991-06-12
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Granted: 1992-08-11
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Expires: 2011-06-12
Abstract
Abstract A fiber-optic communication system (10) employs a Fabry-Perot laser (14) that launches its output onto a single-mode pigtail (16) physically coupled to a mode scrambler (22), which is air coupled to a transmission medium consisting of multi-mode fiber-optic cable. Because the mode scrambler (22) divides the laser output power among many modes, the fraction of any reflected light that is coupled back into the cavity of the laser (14) can be made small enough to permit sufficient laser coherence for high-data-rate-transmission.
Inventors
- 👤 Bruce A. Schofield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:27
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/25; H04B10/2581; G; G02; G02B; G02B6/00; G02B6/10; G02B6/14; G02B6/24; G02B6/42; G02B6/4201; G02B6/4204; G02B6/4207
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
153 words
For launching light of a given wavelength into a transmission cable capable of supporting a plurality of propagation modes of the given wavelength, a transmission apparatus comprising: A) a laser that generates light of the given wavelength; B) a pigtail optically coupled to the laser for introduction of laser light into one end of the pigtail; and C) a mode scrambler that supports more propagation modes than the pigtail can, has first and second ends, is optically coupled physically at its first end to the other end of the pigtail, and is adapted for optical coupling at its second end to a transmission cable, whereby the power in laser light reflected back into the mode scrambler is divided among a plurality of modes in the mode scrambler so that only a fraction of the power in any reflected light thus scrambled is coupled back into the pigtail and thereby returned to the laser.
Claim 2
Dependent Claim
153 words
For launching light of a given wavelength into a transmission cable capable of supporting a plurality of propagation modes of the given wavelength, a transmission apparatus comprising: A) a laser that generates light of the given wavelength; B) a pigtail optically coupled to the laser for introduction of laser light into one end of the pigtail; and C) a mode scrambler that supports more propagation modes than the pigtail can, has first and second ends, is optically coupled physically at its first end to the other end of the pigtail, and is adapted for optical coupling at its second end to a transmission cable, whereby the power in laser light reflected back into the mode scrambler is divided among a plurality of modes in the mode scrambler so that only a fraction of the power in any reflected light thus scrambled is coupled back into the pigtail and thereby returned to the laser.
Claim 3
Dependent Claim
15 words
A transmission apparatus as defined in claim 1 wherein the laser is a Fabry-Perot laser.
Claim 4
Dependent Claim
25 words
A transmission apparatus as defined in claim 1 wherein the ratio of the scrambler core area to the pigtail core area is at least two.
Claim 5
Dependent Claim
25 words
A transmission apparatus as defined in claim 3 wherein the ratio of the scrambler core area to the pigtail core area is at least thirty-nine.
Claim 6
Dependent Claim
22 words
A transmission apparatus as defined in claim 4 wherein the pigtail can support only a single propagation mode at the given wavelength.
Claim 7
Dependent Claim
22 words
A transmission apparatus as defined in claim 3 wherein the pigtail can support only a single propagation mode at the given wavelength.
Claim 8
Dependent Claim
22 words
A transmission apparatus as defined in claim 2 wherein the pigtail can support only a single propagation mode at the given wavelength.
Claim 9
Dependent Claim
22 words
A transmission apparatus as defined in claim 1 wherein the pigtail can support only a single propagation mode at the given wavelength.
Claim 10
Dependent Claim
174 words
For launching light of a given wavelength into a transmission cable capable of supporting a plurality of propagation modes of the given wavelength, a transmission apparatus comprising: A) a Fabry-Perot laser that generates laser light of the given wavelength; B) a pigtail capable of supporting only a single propagation mode at the given wavelength and optically coupled to the laser for introduction of the laser light into one end of the pigtail; and C) a mode scrambler having first and second ends and a core area at least thirty-nine times that of the pigtail, the mode scrambler being optically coupled physically at its first end to the other end of the pigtail and adapted for optical coupling at its second end to a transmission cable, whereby the power in laser light reflected back into the mode scrambler is divided among a plurality of modes in the mode scrambler so that only a fraction of the power in any reflected light thus scrambled is coupled back into the pigtail and thereby returned to the laser.
Claim 11
Dependent Claim
174 words
For launching light of a given wavelength into a transmission cable capable of supporting a plurality of propagation modes of the given wavelength, a transmission apparatus comprising: A) a Fabry-Perot laser that generates laser light of the given wavelength; B) a pigtail capable of supporting only a single propagation mode at the given wavelength and optically coupled to the laser for introduction of the laser light into one end of the pigtail; and C) a mode scrambler having first and second ends and a core area at least thirty-nine times that of the pigtail, the mode scrambler being optically coupled physically at its first end to the other end of the pigtail and adapted for optical coupling at its second end to a transmission cable, whereby the power in laser light reflected back into the mode scrambler is divided among a plurality of modes in the mode scrambler so that only a fraction of the power in any reflected light thus scrambled is coupled back into the pigtail and thereby returned to the laser.
Claim 12
Dependent Claim
159 words
For transmitting optical signals to an optical receiver, an optical communications system comprising: A) a laser that generates laser light of a given wavelength; B) a pigtail optically coupled to the laser for introduction of the laser light into one end of the pigtail; C) a mode scrambler that supports more propagation modes than the pigtail can, has first and second ends, and is optically coupled physically at its first end to the other end of the pigtail; and D) a fiber-optic transmission cable optically coupled at one end to the second end of the mode scrambler and adapted for optical coupling at its other end to an optical receiver, whereby the power in laser light reflected back into the mode scrambler is divided among a plurality of modes in the mode scrambler so that only a fraction of the power in any reflected light thus scrambled is coupled back into the pigtail and thereby returned to the laser.
Claim 13
Dependent Claim
159 words
For transmitting optical signals to an optical receiver, an optical communications system comprising: A) a laser that generates laser light of a given wavelength; B) a pigtail optically coupled to the laser for introduction of the laser light into one end of the pigtail; C) a mode scrambler that supports more propagation modes than the pigtail can, has first and second ends, and is optically coupled physically at its first end to the other end of the pigtail; and D) a fiber-optic transmission cable optically coupled at one end to the second end of the mode scrambler and adapted for optical coupling at its other end to an optical receiver, whereby the power in laser light reflected back into the mode scrambler is divided among a plurality of modes in the mode scrambler so that only a fraction of the power in any reflected light thus scrambled is coupled back into the pigtail and thereby returned to the laser.
Claim 14
Dependent Claim
24 words
An optical communications system as defined in claim 10 wherein the transmission cable can support a plurality of propagation modes at the given wavelength.
Claim 15
Dependent Claim
17 words
An optical communications system as defined in claim 11 wherein the transmission cable is a graded-index cable.
Claim 16
Dependent Claim
23 words
An optical communications system as defined in claim 12 wherein the pigtail can support only a single propagation mode at the given wavelength.
Claim 17
Dependent Claim
23 words
An optical communications system as defined in claim 11 wherein the pigtail can support only a single propagation mode at the given wavelength.
Claim 18
Dependent Claim
23 words
An optical communications system as defined in claim 10 wherein the pigtail can support only a single propagation mode at the given wavelength.
Claim 19
Dependent Claim
16 words
An optical communications system as defined in claim 10 wherein the laser is a Fabry-Perot laser.
Claim 20
Dependent Claim
22 words
A transmission apparatus as defined in claim 16 wherein the pigtail can support only a single propagation mode at the given wavelength.
Claim 21
Dependent Claim
29 words
An optical communications system as defined in claim 10 wherein the ratio of the area of the scrambler core to that of the pigtail core is at least two.
Claim 22
Dependent Claim
29 words
An optical communications system as defined in claim 18 wherein the ratio of the area of the scrambler core to that of the pigtail core is at least thirty-nine.
Claim 23
Dependent Claim
22 words
A transmission apparatus as defined in claim 19 wherein the pigtail can support only a single propagation mode at the given wavelength.
Claim 24
Dependent Claim
22 words
A transmission apparatus as defined in claim 18 wherein the pigtail can support only a single propagation made at the given wavelength.
Claim 25
Dependent Claim
189 words
For transmitting optical signals to an optical receiver, an optical communications system comprising: A) a Fabry-Perot laser that generates laser light of a given wavelength, B) a pigtail capable of supporting only a single propagation mode at the given wavelength and optically coupled to the laser for introduction of the laser light into one end of the pigtail; C) a mode scrambler having first and second ends and a core area at least thirty-nine times that of the pigtail and being optically coupled physically at its first end to the other end of the pigtail; and D) a graded-index fiber-optic transmission cable capable of supporting a plurality of propagation modes of the given wavelength, optically coupled at one end to the second end of the mode scrambler, and adapted for optical coupling at its other end to an optical receiver, whereby the power in laser light reflected back into the mode scrambler is divided among a plurality of modes in the mode scrambler so that only a fraction of the power in any reflected light thus scrambled is coupled back into the pigtail and thereby returned to the laser.
Claim 26
Dependent Claim
189 words
For transmitting optical signals to an optical receiver, an optical communications system comprising: A) a Fabry-Perot laser that generates laser light of a given wavelength, B) a pigtail capable of supporting only a single propagation mode at the given wavelength and optically coupled to the laser for introduction of the laser light into one end of the pigtail; C) a mode scrambler having first and second ends and a core area at least thirty-nine times that of the pigtail and being optically coupled physically at its first end to the other end of the pigtail; and D) a graded-index fiber-optic transmission cable capable of supporting a plurality of propagation modes of the given wavelength, optically coupled at one end to the second end of the mode scrambler, and adapted for optical coupling at its other end to an optical receiver, whereby the power in laser light reflected back into the mode scrambler is divided among a plurality of modes in the mode scrambler so that only a fraction of the power in any reflected light thus scrambled is coupled back into the pigtail and thereby returned to the laser.
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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) | 1995-08-11 | 1996-02-10 | 1996-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-11 | 2000-02-10 | 2000-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-11 | 2004-02-10 | 2004-08-11 | $7700.00 | Window Closed / Lapsed |