Integrated bi-directional dual axial gradient refractive index/diffraction grating wavelength division multiplexer

• US 5,999,672 A
• Filed: 12/13/1997
• Issued: 12/07/1999
• Est. Priority Date: 12/13/1997
• Status: Expired due to Fees

• Current Assignee: Auxora
• Original Assignee: Light Chip, Inc.
• Inventors: Chen, Ray T., Hunter, Boyd V., Wade, Robert K., Dempewolf, Joseph R.
• Primary Examiner(s): Bovernick, Rodney
• Assistant Examiner(s): Wise, Robert E.
• Application Number:
  US08/990,199
• Time in Patent Office: 724 Days
• Field of Search: 385/14, 385/24, 385/37, 385/46
• US Class Current: 385/37
• CPC Class Codes: G02B 6/29307 components assembled in or forming a solid transparent unitary block, e.g. for facilitating component alignment
• CPC Class Codes: G02B 6/2931 Diffractive element operating in reflection
• CPC Class Codes: G02B 6/2938 for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM

Abstract

A wavelength division multiplexer/demultiplexer is provided that integrates axial gradient refractive index elements with a diffraction grating to provide efficient coupling from a plurality of input optical sources (each delivering a single wavelength to the device) which are multiplexed to a single polychromatic beam for output to a single output optical source. The device comprises: (a) means for accepting optical input from at least one optical source, the means including a planar surface; (b) a first coupler element comprising (1) a first axial gradient refractive index collimating lens having a planar entrance surface onto which the optical input is incident and (2) a first homogeneous index boot lens affixed to the first collimating lens and having a planar exit surface from which optical light exits; (c) a diffraction grating formed on the planar exit surface which combines a plurality of angularly separated diffracted wavelengths from the optical light; (d) a reflecting element for reflecting the plurality of diffracted wavelengths; (e) a second coupler element comprising (1) a second homogeneous index boot lens having a planar entrance surface onto which said plurality of diffracted wavelengths is incident and (2) a second axial gradient refractive index collimating lens affixed to the second homogeneous index boot lens; and (f) means for outputting at least one multiplexed, polychromatic output beam to an optical receiver, the means including the planar back surface. The device may be operated in either the forward or the reverse direction.

Claims

1. An integrated axial gradient refractive index/diffraction grating wavelength division device including:

(a) means for accepting at least one optical beam containing at least one wavelength from an optical source, said means including a planar front surface onto which said at least one optical beam is incident;

(b) a first coupler subsystem comprising (1) a first axial gradient refractive index collimating lens operatively associated with said planar front surface, and (2) a first homogeneous index boot lens affixed to said first axial gradient refractive index collimating lens and having a planar exit surface from which said at least one optical beam exits;

(c) a diffraction grating formed at said planar exit surface of said first coupler subsystem for combining a plurality of spatially separated diffracted wavelengths from said at least one optical beam into at least one multiplexed, polychromatic optical beam;

(d) a second coupler subsystem comprising (1) a second homogeneous index boot lens having a planar front surface onto which said at least one multiplexed, polychromatic optical beam is incident, (2) a second axial gradient refractive index collimating lens affixed to said second homogeneous index boot lens, and (3) a planar back surface from which said at least one multiplexed, polychromatic optical beam exits, said planar back surface being operatively associated with said second axial gradient refractive index collimating lens; and

(e) means for outputting said at least one multiplexed, polychromatic optical beam to an optical receiver, said means including said planar back surface.

2. The device of claim 1 further including a reflecting element for reflecting the plurality of diffracted wavelengths to create a compact, optically folded device.

3. The device of claim 2 wherein said reflecting element is provided with a beveled surface at an angle that is normal to a center wavelength diffracted by said diffraction grating, said beveled surface being mirrored so that incident wavelengths from said diffraction grating are reflected toward said second coupler subsystem.

4. The device of claim 2 further including at least one electrooptical element for refracting the plurality of wavelengths to provide channel routing capabilities.

5. The device of claim 4 further comprising a non-linear electrooptic element between said reflecting element and said second coupler subsystem.

6. The device of claim 4 further comprising an array of individually addressable, non-linear, beamsteering elements between said optical source and said first coupler subsystem.

7. The device of claim 1 further including a beamsplitting passive or controllable mirror integrated within any of said device elements to provide for splitting said at least one optical beam into separate portions of said device for bidirectional multiplexing and demultiplexing capabilities.

8. The device of claim 1 wherein said optical source is selected from the group consisting of optical fibers, lasers, and laser diodes.

9. The device of claim 8 wherein said optical source comprises at least one optical fiber transmitting a plurality of wavelengths.

10. The device of claim 8 wherein said optical source comprises a one-dimensional array of optical fibers.

11. The device of claim 8 wherein said optical source comprises a two-dimensional array of optical fibers.

12. The device of claim 8 wherein said optical source comprises a one-dimensional array of laser diodes.

13. The device of claim 8 wherein said optical source comprises a two-dimensional array of laser diodes.

14. The device of claim 1 wherein said optical receiver is selected from the group consisting of optical fibers and photodetectors.

15. The device of claim 14 wherein said optical receiver comprises a one-dimensional array of optical fibers.

16. The device of claim 14 wherein said optical receiver comprises a two-dimensional array of optical fibers.

17. The device of claim 14 wherein said optical receiver comprises a one-dimensional array of photodetectors.

18. The device of claim 14 wherein said optical receiver comprises a two-dimensional array of photodetectors.

19. The device of claim 1 wherein said at least one optical beam is incident on said first coupler subsystem and exits from said second coupler subsystem, thereby acting as a multiplexer.

20. The device of claim 19 wherein more than one said optical beam is incident on said first coupler subsystem and exits from said second coupler subsystem as a combined multiplexed, polychromatic optical beam.

21. The device of claim 1 wherein said at least one optical beam is incident on said second coupler subsystem and exits from said first coupler subsystem, thereby acting as a demultiplexer.

22. The device of claim 21 wherein at least one optical beam is incident on said second coupler subsystem and exits from said first coupler subsystem as a plurality of spatially separated optical beams.

23. The device of claim 1 further comprising at least one homogeneous element between said accepting means and said first coupler subsystem or between said second coupler subsystem and said outputting means.

24. The device of claim 23 comprising one said homogeneous element between said accepting means and said first coupler subsystem and one said homogeneous element between said second coupler subsystem and said outputting means.

25. The device of claim 1 further including at least one electrooptical element for blocking either an individual wavelength or a plurality of wavelengths to provide channel blocking capabilities.

26. The device of claim 1 wherein said first coupler subsystem and said second coupler subsystem each provide a specifically desired function for channel output intensity as a function of wavelength.