Claims
- 1. An optical add and drop multiplexer (OADM), comprising:
A ferrule having an input side and an output side, and an opening formed therethrough, input, output, add and drop fibers contained in said ferrule, A collimating lens positioned on the output side of the ferrule, A free-space filter adjacent to the collimating lens and positioned such that optical signals in the filter's reflection band from the input fiber are reflected back through the collimating lens to the output fiber and optical signals in the filter's transmission band from the input or add fibers are transmitted through the filter, and A reflector positioned behind and at angle to said filter such that optical signals transmitted through the filter from the input and add fibers are reflected back through the filter and collimating lens to said drop and output fibers, respectively.
- 2. The OADM of claim 1, wherein said fibers are arranged within said ferrule such that at the output side of said ferrule the input and drop fibers and the output and add fibers are on opposing diagonals that intersect at or near their midpoints.
- 3. The OADM of claim 2, wherein the collimating lens has a central axis, said fibers being arranged such that a point halfway between the input and output fibers lies on or near the central axis of the collimating lens.
- 4. The OADM of claim 2, wherein the ferrule has a central axis that extends through the center of the opening, said fibers being arranged such that the intersection of the opposing diagonals lies at or near the central axis of the ferrule.
- 5. The OADM of claim 2, wherein the opening in the ferrule and the arrangement of the fibers is substantially square.
- 6. The OADM of claim 2, wherein the fibers are substantially in contact with each other so that the fiber-to-fiber spacings are set by the fiber diameters.
- 7. The OADM of claim 1, wherein the input, output, add and drop fibers extend outwardly from one side of the OADM.
- 8. The OADM of claim 1, wherein the collimating lens is a C-lens or a GRIN lens.
- 9. The OADM of claim 1, wherein the filter comprises a thin-film filter.
- 10. The OADM of claim 1, wherein the filter comprises a coating on a back surface of the filter and wherein the back surface of the filter is positioned adjacent to the reflector.
- 11. The OADM of claim 1, wherein said ferrule and said fibers are inside a first glass tube comprising a 4-fiber pigtail assembly, said collimating lens and said filter are in a second glass tube comprising a lens assembly, said 4-fiber pigtail assembly and said lens assembly aligned and bonded together to form an aligned filter assembly, which is bonded to a housing, said reflector being bonded to a reflector mount, which is aligned and bonded to said housing.
- 12. The OADM of claim 11, wherein the fibers are arranged with the input and drop fibers and the output and add fibers on opposing diagonals that intersect at or near their midpoints with the midpoint between the input and output fibers at or near the central axis of the collimating lens.
- 13. An optical add and drop multiplexer (OADM), comprising:
A 4-fiber pigtail having an input fiber configured to receive a multiplexed optical signal comprising a plurality of optical channels, an add fiber, a drop fiber and an output fiber, A lens that collimates an optical beam path coming out of each fiber such that a central axis of each optical beam path substantially intersects at or near a focal point of the lens, wherein the fibers are arranged with the input and drop fibers and the output and add fibers on opposing diagonals that intersect at or near their midpoints, and wherein a point halfway between the input and output fibers lies on or near the central axis of the collimating lens, A free-space filter positioned at or near the lens focal point such that an optical channel in the reflection band of the filter is reflected back through the collimating lens to the output fiber and a drop signal or add signal in the transmission band of the filter is transmitted through the filter, and A reflector positioned at or near the lens focal point such that the add and the drop signals are reflected back through the filter and the collimating lens to the output and drop fibers, respectively.
- 14. The OADM of claim 13, wherein the fibers are arranged in a substantially square configuration.
- 15. The OADM of claim 13, wherein the fibers are substantially in contact with each other so that the fiber-to-fiber spacings are set by the fiber diameters.
- 16. The OADM of claim 13, wherein the input, output, add and drop fibers extend outwardly from one side of the 4-fiber pigtail.
- 17. The OADM of claim 16, wherein the filter comprises a coating on a back surface positioned towards the reflector.
- 18. The OADM of claim 13, wherein said 4-fiber pigtail includes a ferrule with said fibers inside a first glass tube, said collimating lens and said filter in a second glass tube to form a lens assembly, said 4-fiber pigtail assembly and said lens assembly being aligned and bonded together to form an aligned filter assembly, which is bonded to a housing, said reflector being bonded to a reflector mount, which is aligned and bonded to said housing.
- 19. An optical add and drop multiplexer (OADM), comprising:
A 4-fiber pigtail having an input fiber, an add fiber, a drop fiber and an output fiber all extending outwardly from an input side of the pigtail and arranged such that at an output side of the pigtail the input and drop fibers and the output and add fibers are on opposing diagonals that intersect at or near their midpoints, A collimating lens having a central axis that lies at or near a point halfway between the input and output fibers, A bandpass filter positioned at or near the focal point of the lens, and A reflector positioned behind the bandpass filter at or near the lens focal point.
- 20. The OADM of claim 19, wherein the collimating lens is a C-lens or a GRIN lens.
- 21. The OADM of claim 19, wherein the filter comprises a thin-film filter.
- 22. The OADM of claim 21, wherein the filter comprises a coating on a back surface towards the reflector.
- 23. The OADM of claim 19, wherein said 4-fiber pigtail includes a ferrule that is formed with said fibers inside a first glass tube, said collimating lens and said filter being formed in a second glass tube to form a lens assembly, said 4-fiber pigtail assembly and said lens assembly being aligned and bonded together to form an aligned filter assembly, which is bonded to a housing, said reflector being bonded to a reflector mount, which is aligned and bonded to said housing.
- 24. An optical add and drop multiplexer (OADM), comprising:
A housing; An aligned filter assembly bonded to the housing, said filter assembly comprising,
A 4-fiber pigtail including input and add and output and drop fibers arranged inside a ferrule on respective diagonals that intersect at or near their midpoints and assembled inside a first glass tube so that all four fibers extend from the same side of the ferrule, and A lens assembly including a collimating lens and filter bonded together and assembled inside a second glass tube, wherein said first and second glass tubes are aligned and bonded together so that a point halfway between the input and output fibers lies on or near a central axis of the collimating lens; and A reflector assembly aligned and bonded to the housing at or near the focal point of the collimating lens, said reflector assembly comprising a mount and a reflector bonded to the mount.
- 25. The OADM of claim 24, wherein the collimating lens is a C-lens or a GRIN lens.
- 26. The OADM of claim 24, wherein the filter comprises a thin-film filter.
- 27. The OADM of claim 26, wherein the filter comprises a coating on its back surface towards the reflector.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of priority under 35 U.S.C. 120 to U.S. application Ser. No. 10/306,332 entitled “3-Port Optical Add-Drop Multiplexer (OADM)” filed on Nov. 27, 2002, the entire contents of which are incorporated by reference.
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
10306332 |
Nov 2002 |
US |
Child |
10387239 |
Mar 2003 |
US |