Resonant reflector for increased wavelength and polarization control

• US 20020106160A1
• Filed: 04/12/2002
• Published: 08/08/2002
• Est. Priority Date: 12/29/2000
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Honeywell International Inc.
• Inventors: Morgan, Robert A., Cox, James A.
• Granted Patent: US 6,836,501 B2
• Time in Patent Office: Days
• US Class Current: 385/49
• CPC Class Codes: G02B 6/29317 Light guides of the optical fibre type
• CPC Class Codes: H01S 2301/163 Single longitudinal mode
• CPC Class Codes: H01S 5/11 Comprising a photonic bandgap structure
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/18319 comprising a periodical structure in lateral directions
• CPC Class Codes: H01S 5/18355 having a defined polarisation
• CPC Class Codes: H01S 5/18358 containing spacer layers to adjust the phase of the light wave in the cavity
• CPC Class Codes: H01S 5/18369 based on dielectric materials
• CPC Class Codes: H01S 5/18377 comprising layers of different kind of materials, e.g. combinations of semiconducting with dielectric or metallic layers
• CPC Class Codes: H01S 5/18386 Details of the emission surface for influencing the near- or far-field, e.g. a grating on the surface
• CPC Class Codes: H01S 5/18388 Lenses
• CPC Class Codes: H01S 5/18397 Plurality of active layers vertically stacked in a cavity for multi-wavelength emission
• CPC Class Codes: H01S 5/4087 emitting more than one wavelength
• CPC Class Codes: H01S 5/423 having a vertical cavity

Abstract

An optical system that includes at least two optical emitters and/or optical receivers that have a corresponding guided-mode grating resonant reflector filter (GMGRF). Each GMGRF is preferably tuned to a unique wavelength and/or polarization by adjusting selected GMGRF parameters, such as the grating period and/or the thickness of the grating or other layers. One advantage of this construction is that the various optical emitters and/or optical receivers may be finely tuned, often lithographically, to provide fine wavelength resolution and/or polarization control. For WDM and WDD applications, this may allow closely-spaced optical transmission channels, and may simplify the wavelength-selective WDM and WDD operations required for simultaneous transmission of the channels.

Claims

1. An optical system, comprising:

at least two optoelectronic emitters, each having a guided-mode grating resonant reflector filter (GMGRF), wherein the GMGRF for each optoelectronic emitter is adapted to select a light output that has a different wavelength and/or polarization, and wherein the light output produced by the at least two optoelectronic emitters are provided to a common optical receiver element.

2. An optical system according to claim 1 wherein:

a first optoelectronic emitter of the at least two optical emitters has a top mirror, a bottom mirror, and a GMGRF positioned adjacent a selected one of the top or bottom mirrors, the GMGRF having a waveguide and a grating, the waveguide and the grating being configured to produce a first light output that has a first wavelength; and

a second optoelectronic emitter of the at least two optoelectronic emitters has a top mirror, a bottom mirror, and a GMGRF positioned adjacent a selected one of the top or bottom mirrors, the GMGRF having a waveguide and a grating, the waveguide and the grating of the second optoelectronic emitter being configured to produce a second light output with a second wavelength, wherein the first wavelength is different from the second wavelength.

3. An optical system according to claim 2 further comprising:

providing means for providing the first and second light outputs to the common optical receiver element.

4. An optical system according to claim 3 wherein the common optical receiver element is an optical fiber.

5. An optical system according to claim 2, wherein the waveguide and the grating of the GMGRF of the first optoelectronic emitter are configured such that a first-diffraction order wave vector of the grating substantially matches a propagating mode of the waveguide.

6. An optical system according to claim 5, wherein the waveguide and the grating of the GMGRF of the second optoelectronic emitter are configured such that a first-diffraction order wave vector of the grating substantially matches a propagating mode of the waveguide.

7. An optical system according to claim 5, wherein the first optoelectronic emitter further comprises:

a cladding or buffer layer positioned between the GMGRF and the selected top or bottom mirror, the cladding or buffer layer being sufficiently thick, or having a sufficiently low refractive index relative to the refractive index of the waveguide, to substantially prevent energy in the evanescent tail of the propagation mode of the waveguide from entering the selected top or bottom mirror.

8. An optical system according to claim 7, wherein the second optoelectronic emitter further comprises:

a cladding or buffer layer positioned between the GMGRF and the selected top or bottom mirror, the cladding or buffer layer being sufficiently thick, or having a sufficiently low refractive index relative to the refractive index of the waveguide, to substantially prevent energy in the evanescent tail of the propagation mode of the waveguide from entering the selected top or bottom mirror.

9. An optical system according to claim 2 wherein a core layer is positioned adjacent the grating of the first optoelectronic emitter, the core layer having a core thickness, and the grating having a grating period and a grating height.

10. An optical system according to claim 9 wherein the core thickness and grating height of the first optoelectronic emitter remain fixed, and the grating period is photolithographically set to produce the first wavelength.

11. An optical system according to claim 10 wherein a core layer is positioned adjacent the grating of the second optoelectronic emitter, the core layer having a core thickness, and the grating having a grating period and a grating height.

12. An optical system according to claim 11 wherein the core thickness and grating height of the second optoelectronic emitter remain fixed, and the grating period is photolithographically set to produce the second wavelength.

13. An optical system according to claim 12 wherein the grating height and core thickness of the first optoelectronic emitter are substantially the same as the grating height and core thickness of the second optoelectronic emitter.

14. An optical system according to claim 9 wherein the grating extends into the core layer of the first optoelectronic emitter, leaving a core depth between the grating and an opposite surface of the core layer, the ratio of the core depth to the grating height being set to produce the first wavelength.

15. An optical system according to claim 14 wherein a core layer is positioned adjacent the grating of the second optoelectronic emitter, the core layer having a core thickness, and the grating having a grating period and a grating thickness, the grating extends into the core layer of the second optoelectronic emitter, leaving a core depth between the grating and an opposite surface of the core layer, the ratio of the core depth to the grating height being set to produce the second wavelength.

16. An optical system according to claim 15 wherein the core thickness of the first optoelectronic emitter and the core thickness of the second optoelectronic emitter are substantially the same.

17. An optical system according to claim 2 wherein the at least two optoelectronic emitters are fabricated on a common substrate.

18. An optical system according to claim 1 wherein the light outputs produced by the at least two optoelectronic emitters are eventually provided to at least two optical receivers, wherein each optical receiver is adapted to selectively receive one of the wavelengths and/or polarizations provided by the at least two optoelectronic emitters.

19. An optical system according to claim 18 the at least two optical receivers include:

a first optoelectronic receiver that includes a top mirror, a bottom mirror, and a resonant reflector positioned adjacent a selected one of the top or bottom mirrors, the GMGRF having a waveguide and a grating, the waveguide and grating being configured to receive a first wavelength; and

a second optoelectronic receiver that includes a top mirror, a bottom mirror, and a GMGRF positioned adjacent a selected one of the top or bottom mirrors, the GMGRF having a waveguide and a grating, the waveguide and grating of the second optoelectronic receiver being configured to produce a second light output with a second wavelength, wherein the first wavelength is different from the second wavelength.

20. An optical system according to claim 19 wherein the first optoelectronic receiver and the second optoelectronic receiver are fabricated on a common substrate.

22. An optical system according to claim 18 further comprising:

a first optoelectronic receiver that is adapted to selectively receive light having the first polarization from the common receiver element; and

a second optoelectronic receiver that is adapted to selectively receive light having the second polarization from the common receiver element.

23. An optical system according to claim 22 wherein:

the first optoelectronic receiver includes a top mirror, a bottom mirror, and a GMGRF positioned adjacent a selected one of the top or bottom mirrors, the GMGRF having a waveguide and a grating, the waveguide and grating being configured to receive the first light output having the first polarization; and

the second optoelectronic receiver includes a top mirror, a bottom mirror, and a GMGRF positioned adjacent a selected one of the top or bottom mirrors, the GMGRF having a waveguide and a grating, the waveguide and grating being configured to receive the second light output having the second polarization, wherein the first polarization is different from the second polarization.

24. An optical system according to claim 20 wherein the first optoelectronic receiver and the second optoelectronic receiver are produced on a common substrate.

21. An optical system, comprising:

a first optoelectronic emitter having a top mirror, a bottom mirror, and a GMGRF positioned adjacent a selected one of the top or bottom mirrors, the GMGRF having a waveguide and a grating, the waveguide and grating being configured to produce a first light output that has a first polarization;

a second optoelectronic emitter having a top mirror, a bottom mirror, and a GMGRF positioned adjacent a selected one of the top or bottom mirrors, the GMGRF having a waveguide and a grating, the waveguide and grating of the second optoelectronic emitter being configured to produce a second light output with a second polarization, wherein the first polarization is different from the second polarization; and

providing means for providing the first and second light outputs to the common optical receiver element.