US4859018A
Expired / Lapsed
US
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Optical fiber bandwidth limiting
Assignee: Nortel Networks Ltd
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Filing: 1987-06-15
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Granted: 1989-08-22
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Expires: 2007-06-15
Abstract
Abstract A bandwidth limiter for an optical fiber transmission path comprises a four-port optical coupler via which an optical signal is passed. A spliced optical fiber provides a loop, from an output to an input of the coupler, with a predetermined propagation delay and attenuation. An alternative arrangement uses two couplers which are coupled together via fibers of different length and hence propagation delay.
Inventors
- 👤 Maurice S. O'Sullivan
- 👤 Hyung B. Kim
- 👤 Vincent C. So
- 👤 Paul J. Vella
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:13
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/25; H04B10/2507; G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2861
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
133 words
A method of limiting bandwidth on an optical fiber transmission path carrying an optical signal, comprising the steps of: supplying the optical signal to a first input, and deriving a bandwidth-limited optical signal from a first output, of an optical signal coupler; and coupling a second output of the coupler to a second input thereof via an optical fiber providing a predetermined propagation delay and a predetermined attenuation; wherein the coupler has a coupling coefficient α from the first input to the second output and a transfer coefficient β from the first and second inputs to the first and second outputs, the optical fiber provides a transfer coefficient β' from the second output to the second input of the coupler whereby the predetermined attenuation is 1-β', and α is substantially equal to (1+ββ')/(1+2ββ').
Claim 2
Independent Claim
133 words
A method of limiting bandwidth on an optical fiber transmission path carrying an optical signal, comprising the steps of: supplying the optical signal to a first input, and deriving a bandwidth-limited optical signal from a first output, of an optical signal coupler; and coupling a second output of the coupler to a second input thereof via an optical fiber providing a predetermined propagation delay and a predetermined attenuation; wherein the coupler has a coupling coefficient α from the first input to the second output and a transfer coefficient β from the first and second inputs to the first and second outputs, the optical fiber provides a transfer coefficient β' from the second output to the second input of the coupler whereby the predetermined attenuation is 1-β', and α is substantially equal to (1+ββ')/(1+2ββ').
Claim 3
Dependent Claim
31 words
A method as claimed in claim 1 and including the step of splicing the optical fiber between the second output and second input of the coupler to provide said predetermined attenuation.
Claim 4
Dependent Claim
148 words
An optical signal bandwidth limiter comprising: optical signal coupling means having first and second inputs and first and second outputs; optical fiber means for supplying an optical signal to the first input and for deriving a bandwidth-limited optical signal from the first output of the coupling means; and an optical fiber path providing a predetermined propagation delay and a predetermined attenuation coupled from the second output to the second input of the coupling means; wherein the coupling means comprises a two-input two-output optical signal coupler having a coupling coefficient α from the first input to the second output and a transfer coefficient β from the first and second inputs to the first and second outputs, the optical fiber path provides a transfer coefficient β' from the second output of the second input of the coupler, whereby the predetermined attenuation is 1-β', and α is substantially equal to (1+ββ')/(1+2ββ').
Claim 5
Dependent Claim
148 words
An optical signal bandwidth limiter comprising: optical signal coupling means having first and second inputs and first and second outputs; optical fiber means for supplying an optical signal to the first input and for deriving a bandwidth-limited optical signal from the first output of the coupling means; and an optical fiber path providing a predetermined propagation delay and a predetermined attenuation coupled from the second output to the second input of the coupling means; wherein the coupling means comprises a two-input two-output optical signal coupler having a coupling coefficient α from the first input to the second output and a transfer coefficient β from the first and second inputs to the first and second outputs, the optical fiber path provides a transfer coefficient β' from the second output of the second input of the coupler, whereby the predetermined attenuation is 1-β', and α is substantially equal to (1+ββ')/(1+2ββ').
Claim 6
Dependent Claim
32 words
A limiter as claimed in claim 3 wherein the optical fiber path comprises an optical fiber having a predetermined length providing said predetermined propagation delay and a splice providing said predetermined attenuation.
References Cited (Backward Citations)
US4136929A
Cited
US4184744A
Cited
US4348075A
Cited
US4368543A
Cited
US4405199A
Cited
US4615582A
Cited
US4511207B1
Cited
US4511207A
Cited
US4479701A
Cited
US4530097A
Cited
US4530603A
Cited
US4469397A
Cited
US4579417A
Cited
US4652079A
Cited
US4708421A
Cited
US4696063A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-21 | 1993-02-20 | 1993-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-21 | 1997-02-20 | 1997-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-21 | 2001-02-20 | 2001-08-22 | $7700.00 | Window Closed / Lapsed |