OPTIMIZED CASCADED RAMAN FIBER-BASED LASER SOURCE FOR HIGH EFFICIENCY MID-INFRARED SPECTRAL GENERATION

• US 20100079853A1
• Filed: 05/01/2009
• Published: 04/01/2010
• Est. Priority Date: 05/01/2008
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Rakich, Peter T., Soljacic, Marin, Fink, Yoel
• Granted Patent: US 8,189,257 B2
• Time in Patent Office: Days
• US Class Current: 359/334
• CPC Class Codes: H01S 2302/00 Amplification / lasing wavelength
• CPC Class Codes: H01S 2303/00 Pumping wavelength
• CPC Class Codes: H01S 3/06725 Fibre characterized by a specific dispersion, e.g. for pulse shaping in soliton lasers or for dispersion compensating [DCF]
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• CPC Class Codes: H01S 3/302 in an optical fibre

Abstract

A laser structure is provided that includes a pulsed source producing a pulsed signal having a low spontaneous noise component to its spectral output and a pulse-shape that is optimally flat. Also, the laser structure includes one or more optical fiber structures receiving the pulsed signal and performing Raman amplification. The pulsed signal is used to excite in the one or more optical fiber structures possessing normal chromatic dispersion, which acts as a nonlinear system for efficient mid-infrared spectral generation.

Claims

1. A laser structure comprising:

a pulsed source producing a pulsed signal having a low spontaneous noise component to its spectral output and a pulse-shape that is optimally flat; and

one or more optical fiber structures receiving said pulsed signal and performing Raman amplification, said pulsed signal is used to excite in the one or more optical fiber structures possessing normal chromatic dispersion, which acts as a nonlinear system for efficient mid-infrared spectral generation.

2. The laser structure of claim 1, wherein said pulsed signal comprises a pulse spectrum being spectrally narrower than the Raman gain associated with the Raman amplification.

3. The laser structure of claim 1, wherein said pulsed signal comprises a temporal shape being optimally flat at their peak-power, with minimal power distributed to wings of the pulse signal.

4. The laser structure of claim 1, wherein said one or more optical fibers are cascaded together to achieve a maximally long wavelengths via spontaneous cascaded Raman amplification.

5. The laser structure of claim 1, wherein said one or more optical fibers comprise a nonlinear element to generate Raman gain.

6. The laser structure of claim 1, wherein said one or more optical fibers comprise normal dispersion over wavelengths of use.

7. The laser structure of claim 1, wherein said one or more optical fibers comprise glass, semiconductor, or polymer.

8. The laser structure of claim 1, wherein said one or more optical fibers comprise concatenated fibers or waveguides of different geometries and materials.

9. The laser structure of claim 1, wherein said pulse signal is generated by the pulsed source by modulation internally or externally.

10. The laser structure of claim 9, wherein said pulsed source uses gain modulation, electro-optic, acoustooptic, electroabsorption, passive or active Q-switching, mode-locking for internal or external modulation.

11. A method of performing Raman amplification comprising:

providing a pulsed source producing a pulsed signal having a low spontaneous noise component to its spectral output and a pulse-shape that is optimally flat;

arranging one or more optical fiber structures to receive said pulsed signal, said pulsed signal is used to excite in the one or more optical fiber structures possessing normal chromatic dispersion, which acts as a nonlinear system for efficient mid-infrared spectral generation.

12. The method of claim 11, wherein said pulsed signal comprises a pulse spectrum being spectrally narrower than the Raman gain associated with the Raman amplification.

13. The method of claim 11, wherein said pulsed signal comprises a temporal shape being optimally flat at their peak-power, with minimal power distributed to wings of the pulse signal.

14. The method of claim 11, wherein said one or more optical fibers are cascaded together to achieve a maximally long wavelengths via spontaneous cascaded Raman amplification.

15. The method of claim 11, wherein said one or more optical fibers comprise a nonlinear element to generate Raman gain.

16. The method of claim 11, wherein said one or more optical fibers comprise normal dispersion over wavelengths of use.

17. The method of claim 11, wherein said one or more optical fibers comprise glass, semiconductor, or polymer.

18. The method of claim 11, wherein said one or more optical fibers comprise concatenated fibers or waveguides of different geometries and materials.

19. The method of claim 11, wherein said pulse signal is generated by the pulsed source by modulation internally or externally.

20. The method of claim 19, wherein said pulsed source uses gain modulation, electro-optic, acoustooptic, electroabsorption, passive or active Q-switching, mode-locking for internal or external modulation.