Fiber optic coupling system

• US 4,783,137 A
• Filed: 07/03/1985
• Issued: 11/08/1988
• Est. Priority Date: 11/15/1983
• Status: Expired due to Fees

• Current Assignee: Raycom Systems Incorporated Colorado
• Original Assignee: Raycom Systems Incorporated Colorado
• Inventors: Dutton, Robert E., Gibson, William A., Roecker, David W., Kosman, Karel J., McConnell, Matthew L., Fife, Jerry L., Cantwell, Richard F., Hargrave, Vernon R.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): HEALY, BRIAN
• Application Number:
  US06/757,987
• Time in Patent Office: 1,224 Days
• Field of Search: 350/96.10, 350/96.15, 350/96.16, 350/96.21, 350/96.20, 350/96.22, 350/96.29, 250/227, 370/4, 370/1, 455/600, 455/606, 455/607, 455/608, 455/612, 455/613, 455/617, 455/618, 455/619, 455/610
• US Class Current: 385/53
• CPC Class Codes: G02B 6/14 Mode converters
• CPC Class Codes: G02B 6/3644 the coupling means being through-holes or wall apertures
• CPC Class Codes: G02B 6/3672 with fibres arranged in a regular matrix array
• CPC Class Codes: G02B 6/3825 with an intermediate part, e.g. adapter, receptacle, linking two plugs
• CPC Class Codes: G02B 6/3834 Means for centering or aligning the light guide within the ferrule
• CPC Class Codes: G02B 6/3845 ferrules comprising functional elements, e.g. filters
• CPC Class Codes: G02B 6/3861 Adhesive bonding adhesives in general C09J
• CPC Class Codes: G02B 6/3863 fabricated by using polishing techniques grinding of the fibre ends B24B19/226
• CPC Class Codes: G02B 6/3889 using encapsulation for protection, e.g. adhesive, molding or casting resin
• CPC Class Codes: G02B 6/403 of the ferrule type, connecting a pair of ferrules
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• CPC Class Codes: G02B 6/4212 the intermediate optical element being a coupling medium interposed therebetween, e.g. epoxy resin, refractive index matching material, index grease, matching liquid or gel
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures
• CPC Class Codes: H04B 10/2589 Bidirectional transmission
• CPC Class Codes: H04B 10/502 LED transmitters

Abstract

A fiber optic coupling device for providing simultaneous bi-directional transmission of optical signals within a single wavelength band over a single fiber optic link cable, including a coupler/connector which precisely aligns and longitudinally separates transmit and receive lightguide fibers and a fiber optic link cable. The cores of the transmit and receive lightguide fibers are tightly aligned with a minimum thickness of cladding for increased packing efficiency, and the end faces of the transmit and receive lightguides are maintained parallel to and a predetermined distance from an end face of the fiber optic link cable to ensure that reflected signals will not be detected as received signals and allow simultaneous distinguishable bi-directional communication of optical data within a single wavelength band.

Claims

1. A fiber optic coupling device for bi-directional transmission of optical signals within a range of wavelengths between a fiber optic link cable and a transmitter/receiver comprising:

receive lightguide for guiding optical input signals over said range of wavelengths to said transmitter/receiver;

transmit lightguide for transmitting optical output signals substantially within said range of wavelengths from said transmitter/receiver;

coupler/connector means, operating without wavelength multiplexing, for axially and angularly aligning said transmit and receive lightguides with said fiber optic link cable;

said coupler/connector means or said fiber optic link cable reducing the intensity of reflected optical signals

thereby allowing simultaneous distinguishable bi-directional optical communication of data within said range of wavelengths.

2. The device of claim 1 wherein said coupler/connector further comprises connector means for maintaining one end face of each of said transmit and receive lightguides parallel to and a predetermined longitudinal distance from an end face of said fiber optic link cable.

3. The device of claim 2 wherein said predetermined longitudinal distance is from 5 to 40 microns.

4. The device of claim 1 wherein said receive and transmit lightguides comprise:

fiber optic core means having a predetermined core diameter; and

cladding means surrounding said fiber optic core means having a thickness which is from 4 percent to 30 percent of said predetermined core diameter so that said fiber optic core means of said receive and transmit lightguides may be closely spaced within said coupler/connector to maximize their packing ratio while maintaining low leakage between said fiber optic core means.

5. The device of claim 4 wherein said coupler/connector further comprises connector means for maintaining one end face of each of the transmit and receive lightguides parallel to and a predetermined longitudinal distance from an end face of said fiber optic link cable.

6. The device of claim 5 wherein said predetermined longitudinal distance is less than about one-half of said predetermined core diameter.

7. The device of claim 4 wherein said receive lightguide includes at least two optical fibers and said transmit lightguide includes at least one optical fiber.

8. The fiber optic coupling device of claim 1 wherein said coupler/connector means together with said fiber optic link cable attenuate reflected optical signals to ensure that reflected signals will not be detected as received signals, allowing said simultaneous distinguishable bi-directional optical communication of data within said range of wavelengths.

29. The device of claim 1 wherein said fiber optic link cable has a preselected minimum length for reducing the intensity of reflected optical signals.

30. The device of claim 1 wherein said fiber optic link cable includes at least one rough polished end face for reducing the intensity of reflected optical signals.

31. The device of claim 1 wherein said coupler/connector means includes mode stripping means adjacent said transmit and receive lightguides for reducing the intensity of reflected optical signals.

9. A fiber optic coupling device for bi-directional transmission of optical signals within a range of wavelengths comprising:

receive lightguide including first core and cladding for guiding optical input signals over said range of wavelengths to a transmitter/receiver;

transmit lightguide including second core and cladding for transmitting optical output signals substantially within said range of wavelengths from said transmitter/receiver;

fiber optic link cable including third core and cladding, said third core having larger diameter than each of said first and second cores;

coupler/connector means, operating without wavelength multiplexing, for maintaining said transmit and receive lightguides in a closely spaced configuration and axially and angularly aligning said transmit and receive lightguides with said fiber optic link cable;

said coupler/connector means or said fiber optic link cable reducing the intensity of reflected optical signals

thereby allowing simultaneous distinguishable bi-directional optical communication of data within said range of wavelengths.

10. The device of claim 9 wherein said third core substantially overlaps both said first core and said second core.

11. The device of claim 9 wherein said first and second claddings surround said first and second cores, respectively, and have thicknesses which are from 4 percent to 30 percent of the diameters of said first and second cores, respectively, so that said first and second cores may be closely spaced within said coupler/connector to maximize their packing ratio while maintaining low leakage between said cores.

12. The fiber optic coupling device of claim 9 wherein said coupler/connector means together with said fiber optic link cable attenuate reflected optical signals to ensure that reflected signals will not be detected as received signals, allowing said simultaneous distinguishable bi-directional optical communication of data within said range of wavelengths.

13. The device of claim 9 wherein said coupler/connector further comprises connector means for maintaining one end face of each of said transmit and receive lightguides parallel to and a predetermined longitudinal distance from an end face of said fiber optic link cable.

14. The device of claim 13 wherein said predetermined longitudinal distance is about one-half the smaller of the diameters of said first and second cores.

32. The device of claim 9 wherein said fiber optic link cable has a preselected minimum length for reducing the intensity of reflected optical signals.

33. The device of claim 9 wherein said fiber optic link cable includes at least one rough polished end face for reducing the intensity of reflected optical signals.

34. The device of claim 9 wherein said coupler/connector means includes mode stripping means adjacent said transmit and receive lightguides for reducing the intensity of reflected optical signals.

15. A bi-directional fiber optic communication device comprising:

receiver for detecting optical input signals, said optical input signals comprising first modulated light within a band of wavelengths corresponding with an LED output, and for generating electrical input signals in response thereto;

transmitter for producing optical output signals, said optical output signals comprising second modulated light within said band of wavelengths, in response to electrical output signals;

receive lightguide connected to said receiver for guiding said optical input signals thereto;

transmit lightguide connected to said transmitter for transmitting said optical signals therefrom;

coupler/connector means for axially and angularly aligning said transmit and receive lightguides with a fiber optic link cable said coupler/connector or said fiber optic link cable reducing the intensity of reflected optical signals;

thereby providing for simultaneous bi-directional coupling of said optical input and output signals between said transmit and receive lightguide means and said fiber optic link cable.

16. The device of claim 15 wherein said coupler/connector further comprises connector means for maintaining one end face of each of said transmit and receive lightguides parallel to and a predetermined longitudinal distance from an end face of said fiber optic link cable.

17. The device of claim 16 wherein said predetermined longitudinal distance is from 5 to 40 microns.

18. The device of claim 15 wherein said receive and transmit lightguides comprise:

fiber optic core means having a predetermined core diameter; and

cladding means surrounding said fiber optic core means having a thickness which is from 4 percent to 30 percent of said predetermined core diameter so that said fiber optic core means of said receive and transmit lightguides may be closely spaced within said coupler/connector to maximize their packing ratio while maintaining low leakage between said fiber optic core means.

19. The device of claim 18 wherein said coupler/connector further comprises connector means for maintaining one end face of each of the transmit and receive lightguides parallel to and a predetermined longitudinal distance from an end face of said fiber optic link cable.

20. The device of claim 19 wherein said predetermined longitudinal distance is less than about one-half of said predetermind core diameter.

35. The device of claim 15 wherein said fiber optic link cable has a preselected minimum length for reducing the intensity of reflected optical signals.

36. The device of claim 15 wherein said fiber optic link cable includes at least one rough polished end face for reducing the intensity of reflected optical signals.

37. The device of claim 15 wherein said coupler/connector means includes mode stripping means adjacent said transmit and receive lightguides for reducing the intensity of reflected optical signals.

21. An optical fiber transmission system for simultaneous bi-directional transmission of optical signals comprising:

first transmitter/receiver means for detecting optical input signals over a range of wavelengths and generating first electrical input signals in response thereto, and for producing optical output signals in a band of wavelengths substantially within said range of wavelengths in response to first electrical output signals;

second transmitter/receiver means for detecting said optical output signals over said range of wavelengths and generating second electrical input signals in response thereto, and for producing said optical input signals substantially within said band of wavelengths in response to second electrical output signals;

fiber optic link cable for transmitting said optical input and output signals between said first and second transmitter/receivers;

coupler/connector means at each end of said fiber optic link cable to attach said link cable to said first and second transmitter/receivers said coupler/connector or said fiber optic link cable reducing the intensity of reflected optical signals thereby allowing simultaneous distinguishable bi-directional communication of said optical input and output signals within said range of wavelengths.

22. The transmission system of claim 21 wherein:

said first and second transmitter/receiver means include transmit lightguides and receive lightguides for transmitting said optical output and input signals to and from said fiber link cable; and

said coupler/connector means axially and angularly aligns an end face of each of said transmit and receive lightguides with an end face of said fiber optic link cable.

23. The transmission system of claim 22 wherein said coupler/connector further comprises connector means for maintaining one end face of each of said transmit and receive lightguides parallel to and a predetermined longitudinal distance from an end face of said fiber optic link cable.

24. The transmission system of claim 23 wherein said predetermined longitudinal distance is from 5 to 40 microns.

25. The transmission system of claim 24 wherein said receive and transmit lightguides comprise:

fiber optic core means having a predetermined core diameter; and

cladding means surrounding said fiber optic core means having a thickness which is from 4 percent to 30 percent of said predetermined core diameter so that said fiber optic core means of said receive and transmit lightguides may be closely spaced within said coupler/connector to maximize their packing ratio while maintaining low leakage between said fiber optic core means.

26. The transmission system of claim 25 wherein said coupler/connector further comprises connector means for maintaining one end face of each of said transmit and receive lightguides parallel to and a predetermined longitudinal distance from an end face of said fiber optic link cable.

27. The transmission system of claim 26 wherein said predetermined longitudinal distance is less than about one-half of said predetermined core diameter.

28. The transmission system of claim 22 wherein:

each said transmit lightguide includes first fiber optic core and cladding;

each said receive lightguide includes second fiber optic core and cladding; and

said fiber optic link cable includes third fiber optic core and cladding, said third fiber optic core having a diameter greater than that of said first and second fiber optic cores.

38. The device of claim 21 wherein said fiber optic link cable has a preselected minimum length for reducing the intensity of reflected optical signals.

39. The device of claim 21 wherein said fiber optic link cable includes at least one rough polished end face for reducing the intensity of reflected optical signals.

40. The device of claim 21 wherein said coupler/connector means includes mode stripping means adjacent said transmit and receive lightguides for reducing the intensity of reflected optical signals.