WAVELENGTH-SELECTABLE LASER DEVICE PROVIDING SPATIALLY-SELECTABLE WAVELENGTH(S)

• US 20130016973A1
• Filed: 01/24/2012
• Published: 01/17/2013
• Est. Priority Date: 07/14/2011
• Status: Active Grant

• Current Assignee: Applied Optoelectronics
• Original Assignee: Applied Optoelectronics
• Inventors: Zheng, Jun, Murry, Stefan J., Guo, Bujin
• Granted Patent: US 9,698,567 B2
• Time in Patent Office: Days
• US Class Current: 398/72
• CPC Class Codes: H01S 3/08063 Graded reflectivity, e.g. variable reflectivity mirror
• CPC Class Codes: H01S 3/105 by controlling the mutual position or the reflecting properties of the reflectors of the cavity , e.g. by controlling the cavity lengthH01S3/10076, H01S3/13 take precedence
• CPC Class Codes: H01S 3/106 by controlling devices placed within the cavity H01S3/10076, H01S3/13 take precedence
• CPC Class Codes: H01S 5/02251 using optical fibres
• CPC Class Codes: H01S 5/02325 Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/143 Littman-Metcalf configuration, e.g. laser - grating - mirror
• CPC Class Codes: H04B 10/506 Multiwavelength transmitters
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0246 using one wavelength per ONU
• CPC Class Codes: H04J 14/025 using one wavelength per ONU, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU
• CPC Class Codes: H04J 14/0282 WDM tree architectures
• CPC Class Codes: H04J 14/0305 in end terminals

Abstract

A wavelength-selectable laser device providing spatially-selectable wavelength(s) may be used to select one or more wavelengths for lasing in a tunable transmitter or transceiver, for example, in a wavelength division multiplexed (WDM) optical system such as a WDM passive optical network (PON). The wavelength-selectable laser device uses a dispersive optical element, such as a diffraction grating, to disperse light emitted from a laser emitter and to direct different wavelengths of the light toward a reflector at different spatial positions such that the wavelengths may be selected by allowing light to be reflected from selected spatial position(s) back into the laser emitter. Thus, the reflected light with a wavelength at the selected spatial position(s) is allowed to complete the laser cavity.

Claims

1. A wavelength-selectable laser device for providing at least one spatially-selectable wavelength, the laser device comprising:

a laser emitter for emitting light at a plurality of wavelengths, the laser emitter including a gain region;

a front reflector configured to reflect light from one side of the laser emitter;

a tunable filter for spatially separating different wavelengths of the light and reflecting at least one spatially-selected wavelength back to the laser emitter, the tunable filter comprising;

a dispersive optical element for reflecting or passing the wavelengths such that different wavelengths are directed from the dispersive optical element at different angles;

a back reflector for reflecting at least one selected wavelength of the wavelengths of light back to the laser emitter based on a spatial location of the selected wavelength(s) relative to the back reflector; and

wherein a laser cavity is formed between the back reflector and the front reflector and including the gain region.

2. The wavelength-selectable laser device of claim 1 wherein the tunable filter further comprises a coating on the back reflector forming at least one opaque region and at least one non-opaque region such that the laser cavity is sufficiently reflective to achieve lasing at the wavelength selected by the non-opaque region(s).

3. The wavelength-selectable laser device of claim 2 wherein the coating is alterable to select the at least one opaque region and the at least one non-opaque region.

4. The wavelength-selectable laser device of claim 1 wherein the tunable filter further comprises a spatial filter located between the dispersive optical element and the back reflector, the spatial filter including at least one opaque region and at least one non-opaque transmissive region such that the laser cavity is sufficiently reflective to achieve lasing at the wavelength selected by the non-opaque transmissive region(s).

5. The wavelength-selectable laser device of claim 4 wherein the spatial filter is electrically controllable to select the at least one opaque region and the at least one non-opaque transmissive region.

6. The wavelength-selectable laser device of claim 1 wherein the back reflector includes a mirror array configured to selectively reflect light from a selected region of the minor array.

7. The wavelength-selectable laser device of claim 6 wherein the mirror array is a microelectromechanical system (MEMS) minor array.

8. The wavelength-selectable laser device of claim 1 wherein the dispersive optical element includes a diffraction grating configured to reflect the wavelengths such that different wavelengths are directed from the diffraction grating to different locations on the back reflector.

9. The wavelength-selectable laser device of claim 1 wherein the dispersive optical element includes a prism configured to pass the wavelengths such that different wavelengths are directed from the prism to different locations on the back reflector.

10. The wavelength-selectable laser device of claim 1 wherein the dispersive optical element includes a volume phase grating (VPG) configured to pass the wavelengths such that different wavelengths are directed from the VPG to different respective locations on the back reflector.

11. The wavelength-selectable laser device of claim 10 wherein the tunable filter further comprises collimating optics for directing the light emitted from the laser emitter to the VPG and focusing optics for focusing the light passing through the VPG at the different wavelengths onto the back reflector such that the different wavelengths are incident on the back reflector at the different respective locations on the back reflector.

12. The wavelength-selectable laser device of claim 10 wherein the front reflector is highly reflective and the laser emitter is configured to provide laser output at the selected wavelength(s) from an opposite side of the laser emitter, and wherein the laser output is passed through the VPG as a zero order direct transmission.

13. The wavelength-selectable laser device of claim 1 wherein the front reflector is partially reflective such that laser output at the selected wavelength(s) is provided from the laser cavity through the front reflector.

14. The wavelength-selectable laser device of claim 1 wherein the front reflector is highly reflective and the laser emitter is configured to provide laser output at the selected wavelength(s) from an opposite side of the laser emitter.

15. The wavelength-selectable laser device of claim 1 wherein the dispersive optical element is fixed such that wavelength selection is provided without moving the dispersive optical element.

16. The wavelength-selectable laser device of claim 1 wherein the tunable filter further comprises control circuitry configured to control selection of the spatially-selected wavelength reflected back to the laser emitter.

17. A wavelength division multiplexed (WDM) system comprising:

a plurality of terminals associated with different respective channel wavelengths and configured to transmit optical signals on the different respective channel wavelengths, at least one of the plurality of terminals including at least a tunable optical transmitter configured to be tuned to a respective channel wavelength, the tunable optical transmitter comprising a wavelength-selectable laser device configured to provide spatially-selectable channel wavelengths by reflecting at least one selected channel wavelength based on a spatial location of the channel wavelength and causing the spatially-selected channel wavelength to complete a laser cavity in the laser device.

18. The WDM system of claim 17 comprising:

at least one central office configured to transmit and receive aggregate WDM optical signals including the channel wavelengths; and

at least one branching point located between the central office and the plurality of terminals, the branching point being configured to combine the optical signals at the channel wavelengths.

19. The WDM system of claim 17 wherein the wavelength-selectable laser device comprises:

a laser emitter for emitting light at a plurality of wavelengths, the laser emitter including a gain region;

a front reflector configured to reflect light from one side of the laser emitter;

a dispersive optical element for reflecting or passing the wavelengths such that different wavelengths are directed from the dispersive optical element at different angles;

a mirror for reflecting at least one selected wavelength of the wavelengths of light back to the laser emitter based on a spatial location of the selected wavelength(s) relative to the minor; and

wherein the laser cavity is formed between the mirror and the back reflector and including the laser emitter.

20. A wavelength-selectable laser device comprising:

a laser emitter for emitting light at a plurality of wavelengths, the laser emitter including a gain region;

a front reflector configured to reflect light from one side of the laser emitter;

a diffraction grating for reflecting or passing the wavelengths such that different wavelengths are directed from the diffraction grating at different angles;

a back reflector for reflecting at least one of the wavelengths of the light back to the laser emitter;

a coating on the back reflector, the coating being configured to form at least one opaque region and at least one non-opaque region such that the back reflector selectively reflects at least one selected wavelength selected by the at least one non-opaque region; and

wherein a laser cavity is formed between the back reflector and the front reflector and including the gain region, and wherein the laser cavity is sufficiently reflective to achieve lasing at the selected wavelength(s).

21. The wavelength-selectable laser device of claim 20 wherein the back reflector is a curved minor.

22. A wavelength-selectable laser device comprising:

a laser emitter for emitting light at a plurality of wavelengths, the laser emitter including a gain region;

a front reflector configured to reflect light from one side of the laser emitter;

a diffraction grating for reflecting or passing the wavelengths such that different wavelengths are directed from the diffraction grating at different angles;

a back reflector for reflecting at least one of the wavelengths of the light back to the laser emitter;

a spatial filter located between the diffraction grating and the back reflector, the spatial filter including at least one opaque region and at least one non-opaque transmissive region such that the back reflector selectively reflects at least one selected wavelength selected by the at least one non-opaque transmissive region; and

wherein a laser cavity is formed between the back reflector and the front reflector and including the gain region, and wherein the laser cavity is sufficiently reflective to achieve lasing at the selected wavelength(s) selected by the non-opaque transmissive region(s).

23. The wavelength-selectable laser device of claim 22 further comprising:

control circuitry for selectively causing the spatial filter to form the at least one opaque region and the at least one non-opaque transmissive region.

24. A wavelength-selectable laser device comprising:

a laser emitter for emitting light at a plurality of wavelengths, the laser emitter including a gain region;

a front reflector configured to reflect light from one side of the laser emitter;

a volume phase grating (VPG) for passing the wavelengths such that different wavelengths are directed from the VPG at different angles;

collimating optics for collimating light emitted from the laser emitter and directing the light to the VPG;

a mirror array configured to selectively reflect light from a selected reflective region of the mirror array;

focusing optics for focusing the light passing through the VPG at the different wavelengths onto the mirror array such that the different wavelengths are incident on the minor array at different respective locations on the minor array; and

wherein a laser cavity is formed between the selected reflected region of the minor array and the front reflector and including the gain region.

25. The wavelength-selectable laser device of claim 24 wherein the front reflector is partially reflective such that laser output at the selected wavelength(s) is provided from the laser cavity through the front reflector.

26. The wavelength-selectable laser device of claim 24 wherein the front reflector is highly reflective and the laser emitter is configured to provide laser output at the selected wavelength(s) from an opposite side of the laser emitter, and wherein the laser output is passed through the VPG as a zero order direct transmission, and further comprising focusing optics for focusing the zero order direct transmission to couple the laser output at the selected wavelength(s).