US4557553A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of wavelength multiplexing in fused single-mode fiber couplers
Assignee: United States Department of the Navy
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Filing: 1981-11-02
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Granted: 1985-12-10
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Expires: 2001-11-02
Abstract
Abstract An apparatus and method of entering and extracting a discrete wavelength of optical data in a single-mode duplex optical data transmission system relies on a selective evanescent field coupling. A continuous single-mode fiber transmits the two wavelengths in opposite directions with respect to each other. A length of a like single-mode fiber is fused to the continuous single-mode fiber such that the product of the fused length and the coupling coefficient of the fiber pairs equals π/2 at one of the optical frequencies to effect one-hundred percent evanescent field coupling to and from the continuous fiber. The product of the coupling coefficient and the fused length equals π at the other optical wavelength to effect a zero percent evanescent field coupling. The other wavelength travels the length of the continuous single-mode fiber uninterrupted while the first wavelength is selectively coupled and decoupled from the fiber as desired.
Inventors
- 👤 Matthew N. McLandrich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:31
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29331; G02B6/29332; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
212 words
A method of entering and extracting a discrete wavelength of optical data transmitted in two wavelengths in a duplex optical data transmission system comprising: transmitting the duplex optical data over a continuous single-mode fiber only, the step of transmitting includes the uninterrupted passing of the other wavelength throughout the continuous single-mode fiber and evanescent field coupling one of two wavelengths of the duplex optical data to and from the system, the evanescent field coupling being effected by there being a one-hundred percent evanescent field coupling at the one wavelength and zero evanescent field coupling at the other wavelength, the step of evanescent field coupling includes the etching away of a precise layer thickness of the claddings of a like single-mode fiber and a portion of the continuous single-mode fiber, the joining of the length l of a like single-mode fiber to the portion of the continuous single-mode fiber to have a discrete center-to-center spacing of the fibers' cores and the fusing of the portion of the continuous single-mode fiber and the length l of the like single-mode fiber together so that the product of the coupling coefficient K and the length l equals π/2 at the one-hundred percent evanescent field coupled wavelength and equals π at the zero evanescent field coupled wavelength.
Claim 2
Independent Claim
212 words
A method of entering and extracting a discrete wavelength of optical data transmitted in two wavelengths in a duplex optical data transmission system comprising: transmitting the duplex optical data over a continuous single-mode fiber only, the step of transmitting includes the uninterrupted passing of the other wavelength throughout the continuous single-mode fiber and evanescent field coupling one of two wavelengths of the duplex optical data to and from the system, the evanescent field coupling being effected by there being a one-hundred percent evanescent field coupling at the one wavelength and zero evanescent field coupling at the other wavelength, the step of evanescent field coupling includes the etching away of a precise layer thickness of the claddings of a like single-mode fiber and a portion of the continuous single-mode fiber, the joining of the length l of a like single-mode fiber to the portion of the continuous single-mode fiber to have a discrete center-to-center spacing of the fibers' cores and the fusing of the portion of the continuous single-mode fiber and the length l of the like single-mode fiber together so that the product of the coupling coefficient K and the length l equals π/2 at the one-hundred percent evanescent field coupled wavelength and equals π at the zero evanescent field coupled wavelength.
Claim 3
Dependent Claim
36 words
A method according to claim 1 in which the two wavelengths are 0.80 microns and 0.85 microns, the fibers are fabricated such that l=two centimeters and the center-to-center spacing of the fibers' cores is eleven microns.
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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) | 1988-12-09 | 1989-06-10 | 1989-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-09 | 1993-06-10 | 1993-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-09 | 1997-06-10 | 1997-12-10 | $7700.00 | Window Closed / Lapsed |