Fiber optics communications modules

• US 4,479,697 A
• Filed: 11/27/1981
• Issued: 10/30/1984
• Est. Priority Date: 08/14/1979
• Status: Expired due to Term

• Current Assignee: Kapany Corporation
• Original Assignee: Kaptron Incorporated
• Inventors: Kapany, Narinder S., Unterleitner, Fred C.
• Primary Examiner(s): Lee, John D.
• Application Number:
  US06/325,256
• Time in Patent Office: 1,068 Days
• Field of Search: 350/96.15, 350/96.16, 350/96.17, 350/96.18, 350/96.19, 350/96.20, 350/96.21, 350/162.23, 350/172, 350/173, 350/174, 350/293, 350/296, 370/1, 370/3, 250/227
• US Class Current: 385/33
• CPC Class Codes: G02B 6/2817 using reflective elements to split or combine optical signals
• CPC Class Codes: G02B 6/2931 Diffractive element operating in reflection
• CPC Class Codes: G02B 6/29361 Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
• CPC Class Codes: G02B 6/2937 In line lens-filtering-lens devices, i.e. elements arranged along a line and mountable in a cylindrical package for compactness, e.g. 3- port device with GRIN lenses sandwiching a single filter operating at normal incidence in a tubular package
• CPC Class Codes: G02B 6/2938 for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
• CPC Class Codes: G02B 6/29385 Channel monitoring, e.g. by tapping channel monitoring in optical transmission systems H04B10/07
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures

Abstract

A fiber optics coupler module has a portion defining a spherical reflective surface characterized by a self-conjugate plane having the property that a point source of light in the self-conjugate plane is imaged in the self-conjugate plane. The coupler includes first and second optical transceiver terminals adapted to register a source, detector, or fiber end at each of first and second conjugate locations within the self-conjugate plane. The reflective surface passes a fraction of light incident thereon, whereupon a portion of light diverging from the first location passes through the reflective surface along a first optical path. Similarly a portion of light diverging from the second location passes through the reflective surface along a second optical path. The coupler further includes focusing means on the side of the reflective surface remote from the first and second locations for imaging light travelling along the first optical path at a third location, and also for imaging light travelling along the second optical path at a fourth location. In a first series of embodiments, the reflective surface is partially transmissive, partially reflective for wavelengths in a given range. In a second series of embodiments, the reflective surface is a dichroic surface. In a third series of embodiments, the coupler uses a plane reflection grating and collimated light.

Claims

1. A fiber optics coupler comprising:

a body of optically transparent material having a portion defining a spherical reflective surface characterized by a self-conjugate plane having the property that a point source of light in said self-conjugate plane is imaged in said self-conjugate plane;

a first optical transceiver terminal adapted to register an optical transceiver at a first location within said self-conjugate plane;

a second optical transceiver terminal adapted to register an optical transceiver at a second location within said self-conjugate plane separated from said first location, said first and second locations being on opposite sides of a radial axis, being displaced equal amounts from said radial axis such that the center of curvature of said spherical reflective surface lies on the straight line between said first and second locations, whereupon said first and second locations are conjugate so that a point source of light at one of said first and second locations is imaged by said reflective surface at the other of said first and second locations;

said reflective surface being characterized by a coefficient of reflection sufficiently less than unity so as to permit a detectable fraction of light incident on said reflective surface to pass therethrough, whereupon a portion of light diverging from said first location passes through said reflective surface along a first optical path and a portion of light diverging from said second location passes through said reflective surface along a second optical path;

focusing means on the side of said reflective surface remote from said self-conjugate plane for imaging light travelling along said first optical path at a third location; and

a third optical transceiver terminal adapted to register an optical transceiver at said third location to provide optical coupling between optical transceivers located at said first and third locations.

5. The invention of claim 1 or 2 or 3 or 4 wherein said focusing means operates to image light travelling along said second optical path at a fourth location, and further comprising a fourth optical transceiver terminal adapted to register an optical transceiver at said fourth location to provide optical coupling between optical transceivers located at said second and fourth locations.

6. The invention of claim 5, and further comprising first and second photodetectors registered at said third and fourth locations by said third and fourth optical transceiver terminals to provide electrical signals representative of the intensity of light diverging from said first and second locations, respectively, whereupon said coupler operates as a directional monitor.

7. The invention of claim 5, and further comprising first, second, third, and fourth optical fibers having respective ends registered at said first, second, third, and fourth locations by said first, second, third, and fourth optical transceiver terminals, whereupon said coupler operates as a data bus coupler.

8. The invention of claim 1 or 2 or 3 or 4, and further comprising first, second, and third fibers having respective ends registered at said first, second, and third locations by said first, second, and third optical transceiver terminals, whereupon said coupler operates as a splitter with respect to light emerging from the end of said first fiber and further operates as a directional coupler by coupling light emerging from the end of said first fiber to the end of said third fiber but not coupling light emerging from the end of said second fiber to the end of said third fiber.

9. The invention of claim 1 or 2 or 3 or 4 wherein said third location is on the side of said reflective surface remote from said first and second locations.

17. The invention of claim 1 or 2 or 10 or 11 or 3 or 4 or 12 or 13 wherein said focusing means comprises a lens having at least two refractive interfaces.

18. The invention of claim 1 or 2 or 10 or 11 or 3 or 4 or 12 or 13 wherein said focusing means comprises a body of optically transparent material having a single curved refracting surface.

19. The invention of claim 1 or 2 or 10 or 11 or 3 or 4 or 12 or 13 wherein said focusing means comprises a graded index lens.

2. A fiber optics coupler comprising:

a body of optically transparent material having a portion defining an imaging reflective surface;

a first optical transceiver terminal adapted to register an optical transceiver at a first location;

a second optical transceiver terminal adapted to register an optical transceiver at a second location conjugate with respect to said first location whereupon a point source of light at one of said first and second locations is imaged by said reflective surface at the other of said first and second locations;

said reflective surface being characterized by a coefficient of reflection sufficiently less than unity so as to permit a detectable fraction of light incident on said reflective surface to pass therethrough whereupon a portion of light diverging from said first location passes through said reflective surface along a first optical path and a portion of light diverging from said second location passes through said reflective surface along a second optical path;

focusing means on the side of said reflective surface remote from said first and second locations for imaging light travelling along said first optical path at a third location; and

a third optical transceiver terminal adapted to register an optical transceiver at said third location to provide optical coupling between optical transceivers located at said first and third locations.

3. A fiber optics coupler comprising:

means defining a spherical reflective surface characterized by a self-conjugate plane having the property that a point source of light in said self-conjugate plane is imaged in said self-conjugate plane;

a first optical transceiver terminal adapted to register an optical transceiver at a first location within said self-conjugate plane;

a second optical transceiver terminal adapted to register an optical transceiver at a second location within said self-conjugate plane separated from said first location, said first and second locations being on opposite sides of a radial axis, being displaced equal amounts from said radial axis such that the center of curvature of said spherical reflective surface lies on the straight line between said first and second locations, whereupon said first and second locations are conjugate so that a point source of light at one of said first and second locations is imaged by said reflective surface at the other of said first and second locations;

said reflective surface being characterized by a coefficient of reflection sufficiently less than unity so as to permit a detectable fraction of light incident on said reflective surface to pass therethrough, whereupon a portion of light diverging from said first location passes through said reflective surface along a first optical path and a portion of light diverging from said second location passes through said reflective surface along a second optical path;

focusing means on the side of said reflective surface remote from said self-conjugate plane for imaging light travelling along said first optical path at a third location; and

a third optical transceiver terminal adapted to register an optical transceiver at said third location to provide optical coupling between optical transceivers located at said first and third locations.

4. A fiber optics coupler comprising:

means defining an imaging reflective surface;

a first optical transceiver terminal adapted to register an optical transceiver at a first location;

a second optical transceiver terminal adapted to register an optical transceiver at a second location conjugate with respect to said first location whereupon a point source of light at one of said first and second locations is imaged by said reflective surface at the other of said first and second locations;

said reflective surface being characterized by a coefficient of reflection sufficiently less than unity so as to permit a detectable fraction of light incident on said reflective surface to pass therethrough whereupon a portion of light diverging from said first location passes through said reflective surface along a first optical path and a portion of light diverging from said second location passes through said reflective surface along a second optical path;

focusing means on the side of said reflective surface remote from said first and second locations for imaging light travelling along said first optical path at a third location; and

a third optical transceiver terminal adapted to register an optical transceiver at said third location to provide optical coupling between optical transceivers located at said first and third locations.

10. A fiber optics coupler comprising:

a body of optically transparent material having a portion defining a spherical dichroic surface that is substantially reflective for light of a first wavelength and substantially transmissive for light of a second wavelength, said surface being characterized by a self-conjugate plane having the property that a point source of light of said first wavelength in said self-conjugate plane is imaged in said self-conjugate plane;

a first optical transceiver terminal adapted to register an optical transceiver at a first location within said self-conjugate plane;

a second optical transceiver terminal adapted to register an optical transceiver at a second location within said self-conjugate plane separated from said first location, said first and second locations being on opposite sides of a radial axis, being displaced equal amounts from said radial axis such that the center of curvature of said spherical dichroic surface lies on the straight line between said first and second locations, whereupon said first and second locations are conjugate so that a point source of light of said first wavelength at one of said first and second locations is imaged at the other of said first and second locations;

whereupon light of said first wavelength diverging from said first location is imaged at said second location while light of said second wavelength diverging from said first location passes through said dichroic surface along a first optical path, and whereupon light of said first wavelength diverging from said second location is imaged by said dichroic surface at said first location while light of said second wavelength diverging from said second location passes through said dichroic surface along a second optical path;

focusing means on the side of said dichroic surface remote from said self-conjugate plane for imaging light travelling along said first optical path at a third location; and

a third optical transceiver terminal adapted to register an optical transceiver at said third location to provide optical coupling at said second wavelength between optical transceivers located at said first and third locations.

14. The invention of claim 10 or 11 or 12 or 13 wherein said focusing means operates to image light travelling along said second optical path at a fourth location, and further comprising a fourth optical transceivers terminal adapted to register an optical transceiver at said fourth location to provide coupling at said second wavelength between optical transceivers located at said second and fourth locations.

15. The invention of claim 10 or 11 or 12 or 13 wherein said focusing means comprises a concave mirror, and wherein said third location is on the same side of said dichroic surface as said first and second locations.

16. The invention of claim 10 or 11 or 13 wherein said third location is on the side of said dichroic surface remote from said first and second locations.

23. The invention of claim 10 or 22 or 11 or 20, and further comprising:

an optical fiber having an end registered at said first location by said first optical transceiver terminal;

a source of light of said first wavelength registered at said second location by said second optical transceiver terminal; and

a detector sensitive to light of said second wavelength registered at said third location by said third optical transceiver terminal;

whereupon said coupler operates as a duplexer.

24. The invention of claim 10 or 22 or 11 or 20, and further comprising:

a fiber having an end registered at said first location by said first optical transceiver terminal;

a source of light of said first wavelength registered at said second location by said second optical transceiver terminal; and

a source of light of said second wavelength registered at said third location by said third optical transceiver terminal;

whereupon said coupler operates as a wavelength multiplexer.

25. The invention of claim 10 or 22 or 11 or 20, and further comprising:

a fiber having an end registered at said first location by said first optical transceiver terminal;

a detector sensitive to light of said first wavelength registered at said second location by said second optical transceiver terminal; and

a detector sensitive to light of said second wavelength registered at said third location by said third optical transceiver;

whereupon said coupler operates as a wavelength demultiplexer.

11. A fiber optics coupler comprising:

a body of optically transparent material having a portion defining an imaging dichroic surface that is substantially reflective for light of a first wavelength and substantially transmissive for light of a second wavelength;

a first optical transceiver terminal adapted to register an optical transceiver at a first location;

a second optical transceiver terminal adapted to register an optical transceiver at a second location conjugate with respect to said first location whereupon a point source of light of said first wavelength at one of said first and second locations is imaged by said dichroic surface at the other of said first and second locations;

whereupon light of said first wavelength diverging from said first location is imaged at said second location while light of said second wavelength diverging from said first location passes through said dichroic surface along a first optical path, and whereupon light of said first wavelength diverging from said second location is imaged by said dichroic reflective surface at said first location while light of said second wavelength diverging from said second location passes through said dichroic surface along a second optical path;

focusing means on the side of said dichroic surface remote from said first and second locations for imaging light travelling along said first optical path at a third location; and

a third optical transceiver terminal adapted to register an optical transceiver at said third location to provide optical coupling at said second wavelength between optical transceivers located at said first and third locations.

12. A fiber optics coupler comprising:

means defining a spherical dichroic surface that is substantially reflective for light of a first wavelength and substantially transmissive for light of a second wavelength, said surface being characterized by a self-conjugate plane having the property that a point source of light of said first wavelength in said self-conjugate plane is imaged in said self-conjugate plane;

a first optical transceiver terminal adapted to register an optical transceiver at a first location within said self-conjugate plane;

a second optical transceiver terminal adapted to register an optical transceiver at a second location within said self-conjugate plane separated from said first location, said first and second locations being on opposite sides of a radial axis, being displaced equal amounts from said radial axis such that the center of curvature of said spherical dichroic surface lies on the straight line between said first and second locations, whereupon said first and second locations are conjugate so that a point source of light of said first wavelength at one of said first and second locations is imaged at the other of said first and second locations;

whereupon light of said first wavelength diverging from said first location is imaged at said second location while light of said second wavelength diverging from said first location passes through said dichroic surface along a first optical path, and whereupon light of said first wavelength diverging from said second location is imaged by said dichroic surface at said first location while light of said second wavelength diverging from said second location passes through said dichroic surface along a second optical path;

focusing means on the side of said dichroic surface remote from said self-conjugate plane for imaging light travelling along said first optical path at a third location; and

a third optical transceiver terminal adapted to register an optical transceiver at said third location to provide optical coupling at said second wavelength between optical transceivers located at said first and third locations.

13. A fiber optics coupler comprising:

means defining an imaging dichroic surface that is substantially reflective for light of a first wavelength and substantially transmissive for light of a second wavelength;

a first optical transceiver terminal adapted to register an optical transceiver at a first location;

a second optical transceiver terminal adapted to register an optical transceiver at a second location conjugate with respect to said first location whereupon a point source of light of said first wavelength at one of said first and second locations is imaged by said dichroic surface at the other of said first and second locations;

whereupon light of said first wavelength diverging from said first location is imaged at said second location while light of said second wavelength diverging from said first location passes through said dichroic surface along a first optical path, and whereupon light of said first wavelength diverging from said second location is imaged by said dichroic reflective surface at said first location while light of said second wavelength diverging from said second location passes through said dichroic surface along a second optical path;

focusing means on the side of said dichroic surface remote from said first and second locations for imaging light travelling along said first optical path at a third location; and

a third optical transceiver terminal adapted to register an optical transceiver at said third location to provide optical coupling at said second wavelength between optical transceivers located at said first and third locations.

20. A coupler for permitting optical signals at first and second wavelengths to be transmitted simultaneously on a single optical fiber comprising:

a first optical transceiver terminal adapted to register an optical transceiver at a first location;

a dichroic beam splitter for directing light of said first wavelength diverging from said first location along a first optical trajectory and light of said second wavelength diverging from said first location along a second optical trajectory, at least a portion of which is separated from said first optical trajectory;

means defining a first spherical reflective surface in said first optical trajectory wherein light of said first wavelength diverging from said first location is imaged at a second location;

means defining a spherical reflective surface in said second optical trajectory wherein light of said second wavelength diverging from said first location is imaged at a third location separate from said second location; and

second and third optical transceiver terminals adapted to register respective optical transceivers at said second and third locations.

21. The invention of claim 20 wherein said dichroic beam splitter and said first reflective surface are one and the same.

22. A fiber optics coupler comprising:

a body of optically transparent material having a portion defining a spherical dichroic surface that is substantially reflective for light of a first wavelength and substantially transmissive for light of a second wavelength, said surface being characterized by a self-conjugate plane having the property that a point source of light of said first wavelength in said self-conjugate plane is imaged in said self-conjugate plane;

a first optical transceiver terminal adapted to register an optical transceiver at a first location within said self-conjugate plane;

a second optical transceiver terminal adapted to register an optical transceiver at a second location within said self-conjugate plane separated from said first location, said first and second locations being on opposite sides of a radial axis, being displaced equal amounts from said radial axis such that the center of curvature of said spherical dichroic surface lies on the straight line between said first and second locations, whereupon said first and second locations are conjugate so that a point source of light of said first wavelength at one of said first and second locations is imaged at the other of said first and second locations;

whereupon light of said first wavelength diverging from said first location is imaged at said second location while light of said second wavelength diverging from said first location passes through said dichroic surface along a first optical path, and whereupon light of said first wavelength diverging from said second location is imaged by said dichroic surface at said first location while light of said second wavelength diverging from said second location passes through said dichroic surface along a second optical path;

mirror means having a portion defining a spherical surface that is at least partly reflective for light of said second wavelength, said mirror means being interposed in said first optical path to reflect light of said second wavelength back through said dichroic surface and image said light thus reflected at a third location proximate said first and second locations; and

a third optical transceiver terminal adapted to register an optical transceiver at said third location to provide optical coupling at said second wavelength between optical transceivers located at said first and third locations.

26. A fiber optics coupler comprising:

a body of optically transparent material having a portion defining a spherical dichroic surface that is substantially reflective for light of a first wavelength and substantially transmissive for light of a second wavelength, said surface being characterized by a self-conjugate plane having the property that a point source of light of said first wavelength in said self-conjugate plane is imaged in said self-conjugate plane,

a first optical transceiver terminal adapted to register an optical transceiver at a first location within said self-conjugate plane;

a second optical transceiver terminal adapted to register an optical transceiver at a second location within said self-conjugate plane separated from said first location, said first and second locations being on opposite sides of a radial axis, being displaced equal amounts from said radial axis such that the center of curvature of said spherical dichroic surface lies on the straight line between said first and second locations, whereupon said first and second locations are conjugate so that a point source of light of said first wavelength at one of said first and second locations is imaged at the other of said first and second locations;

whereupon light of said first wavelength diverging from said first location is imaged at said second location while light of said second wavelength diverging from said first location passes through said dichroic surface along a first optical path, and whereupon light of said first wavelength diverging from said second location is imaged by said dichroic surface at said first location while light of said second wavelength diverging from said second location passes through said dichroic surface along a second optical path; and

a detector responsive to light of said second wavelength interposed in said first optical path.

27. The invention of claim 26, and further comprising:

an optical fiber having an end registered at said first location by said first optical transceiver terminal; and

a source of light of said first wavelength registered at said second location by said second optical transceiver terminal whereupon said coupler operates as a duplexer.

28. The invention of claim 26, and further comprising:

a fiber having an end registered at said first location by said first optical transceiver terminal; and

a detector sensitive to light of said first wavelength registered at said second location by said second optical transceiver terminal;

whereupon said coupler operates as a wavelength demultiplexer.

29. A fiber optics coupler comprising:

a body of optically transparent material having a portion defining a spherical reflective surface characterized by a focal distance having the property that a point source of light at said focal distance from said reflective surface is collimated by said reflective surface;

a main optical transceiver terminal adapted to register an optical transceiver at a main location located at said focal distance from said reflective surface;

first and second branch optical transceiver terminals adapted to register respective first and second branch optical transceivers at respective first and second branch locations located at said focal distance from said reflective surface; and

means defining a plane reflection grating in the path of collimated light arising from reflection of light diverging from said main location;

said grating being oriented to reflect collimated light of a first wavelength toward said reflective surface for imaging at said first branch location and to reflect collimated light of a second wavelength toward said reflective surface to be imaged at said second branch location.

30. A fiber optics coupler comprising:

means defining a spherical dichroic surface that is substantially reflective for light of a first wavelength and substantially transmissive for light of a second wavelength, said surface being characterized by a self-conjugate plane having the property that a point source of light of said first wavelength in said self-conjugate plane is imaged in said self-conjugate plane;

a first optical transceiver terminal adapted to register an optical transceiver at a first location within said self-conjugate plane;

a second optical transceiver terminal adapted to register an optical transceiver at a second location within said self-conjugate plane separated from said first location, said first and second locations being on opposite sides of a radial axis, being displaced equal amounts from said radial axis such that the center of curvature of said spherical dichroic surface lies on the straight line between said first and second locations, whereupon said first and second locations are conjugate so that a point source of light of said first wavelength at one of said first and second locations is imaged at the other of said first and second locations;

whereupon light of said first wavelength diverging from said first location is imaged at said second location while light of said second wavelength diverging from said first location passes through said dichroic surface along a first optical path, and whereupon light of said first wavelength diverging from said second location is imaged by said dichroic surface at said first location while light of said second wavelength diverging from said second location passes through said dichroic surface along a second optical path;

mirror means having a portion defining a spherical surface that is at least partly reflective for light of said second wavelength, said mirror means being interposed in said first optical path to reflect light of said second wavelength back through said dichroic surface and image said light thus reflected at a third location proximate said first and second locations; and

a third optical transceiver terminal adapted to register an optical transceiver at said third location to provide optical coupling at said second wavelength between optical transceivers located at said first and third locations.

31. A fiber optics coupler comprising:

means defining an imaging reflective surface characterized by a focal distance having the property that a point source of light at said focal distance from said reflective surface is collimated by said reflective surface;

a main optical transceiver terminal adapted to register an optical transceiver at a main location located at said focal distance from said reflective surface;

first and second branch optical transceiver terminals adapted to register respective first and second branch optical transceivers at respective first and second branch locations located at said focal distance from said reflective surface; and

means defining a plane reflection grating in the path of collimated light arising from reflection of light diverging from said main location;

said grating being oriented to reflect collimated light of a first wavelength toward said reflective surface for imaging at said first branch location and to reflect collimated light of a second wavelength toward said reflective surface to be imaged at said second branch location.