Laser system

• US 20080069159A1
• Filed: 05/18/2007
• Published: 03/20/2008
• Est. Priority Date: 05/19/2006
• Status: Active Grant

• Current Assignee: Menlo Systems GmbH
• Original Assignee: Menlo Systems GmbH
• Inventors: Fischer, Marc, Adel, Peter, Mei, Michael, Holzwarth, Ronald
• Granted Patent: US 7,804,863 B2
• Time in Patent Office: Days
• US Class Current: 372/32
• CPC Class Codes: G01N 21/6458 Fluorescence microscopy fluorescence microscopes per se G02B21/0076 and G02B21/16
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/302 in an optical fibre

Abstract

The invention concerns a laser system with a frequency comb generator for generating a comb of optical frequencies having an offset frequency and a plurality of equidistant modes, wherein the laser system further preferably comprises at least one stabilizer for stabilizing the frequency comb onto a certain offset frequency and/or onto a certain mode spacing. The laser system further comprises an optical amplifier for amplifying the frequency comb coupled out of the frequency comb generator, the amplification factor of this amplifier being variable; and the amplifier is followed by a Raman medium for generating a Raman shift of the frequency comb.

Claims

1. A Laser system with a frequency comb generator for generating a frequency comb of optical frequencies with an offset frequency and a plurality of equidistant modes, wherein an optical amplifier is provided for amplifying the frequency comb coupled out of the frequency comb generator,

wherein the amplification factor of the amplifier is variable,

wherein the amplifier is followed by a Raman medium adapted for generating a Raman shift of the frequency comb, and

wherein the Raman medium is configured such that a soliton is generated from the frequency comb, and that a soliton self-frequency shift in the Raman medium leads to a frequency shift of the soliton.

2. Laser system according to claim 1, wherein the laser system further comprises at least one stabilizer for stabilizing the frequency comb onto a predetermined offset frequency or onto a predetermined mode spacing.

3. Laser system according to claim 1, wherein the optical amplifier comprises an optically pumped, ion doped optical fiber.

4. Laser system according to claim 1, wherein a diode laser is provided as a pump source for the amplifier.

5. Laser system according to claim 4, wherein the amplification factor of the amplifier is controllable via the current at the diode laser.

6. Laser system according to claim 1, wherein the amplifier generates a first Raman shift of the frequency comb before the Raman medium.

7. Laser system according to claim 1, wherein the Raman medium comprises an optical fiber.

8. Laser system according to claim 7, wherein the optical fiber is polarization preserving.

9. Laser system according to claim 1, wherein the Raman medium is connected to an optical fiber of the amplifier by means of a splice connection.

10. Laser system according to claim 1, wherein the Raman medium is followed by a frequency dependent attenuator.

11. Laser system according to claim 10, wherein the attenuation degree of the attenuator increases towards lower frequencies.

12. Laser system according to claim 10, wherein the attenuation degree of the attenuator linearly increases towards lower frequencies.

13. Laser system according to claim 10, wherein the attenuator is a passive element.

14. Laser system according to claim 10, wherein the attenuator comprises a mirror, the reflectivity of which increases or decreases towards lower frequencies.

15. Laser system according to claim 10, wherein the attenuator comprises a mirror, the transmissivity of which increases or decreases towards lower frequencies.

16. Laser system according to claim 10, wherein the attenuator comprises an optical fiber.

17. Laser system according to claim 16, wherein the optical fiber is arranged with a curvature.

18. Laser system according to claim 16, wherein a radius of curvature of the optical fiber at least in portions of the fiber has a value of 15 to 100 millimeters, in particular 25 to 40 millimeters.

19. Laser system according to claim 16, wherein the attenuation degree of the attenuator per frequency interval is variable.

20. Laser system according to claim 16, wherein the radius of curvature of the optical fiber is variably adjustable.

21. Laser system according to claim 16, wherein an optical fiber of the amplifier is connected to an optical fiber of the Raman medium by means of a splice connection.

22. Laser system according to claim 1, further comprising a frequency converter.

23. Laser system according to claim 1, wherein the repetition rate of the frequency comb generator is between 80 and 500 MHz.

24. Laser system according to claim 1, wherein the repetition rate of the frequency comb generator is between 150 and 300 MHz.

25. Laser system according to claim 1, wherein the Raman medium comprises a plurality of Raman media, and the optical properties of one Raman medium are different from another Raman medium.

26. Laser system according to claim 1, wherein the Raman medium comprises a plurality of optical fibers, and the optical properties of one fiber are different from another fiber.

27. Laser system according to claim 26, wherein the fibers are different in their nonlinear optical properties or in their dispersion properties.

28. Laser system according to claim 26, wherein the fibers are spliced to each other.

29. Laser system according to claim 26, wherein the fibers are different in the cross sectional area of their cores.

30. Use of a frequency comb generated by a laser system according to claim 1 for measuring an optical frequency.

31. Use of a frequency comb generated by a laser system according to claim 1 for generating an optical reference frequency.

32. Use of a frequency comb generated by a laser system according to claim 1 in an optical clock.

33. Use of a frequency comb generated by a laser system according to claim 1 for comparing two optical frequencies.

34. Use of a frequency comb generated by a laser system according to claim 1 in the field of telecommunication.

35. Use of a frequency comb generated by a laser system according to claim 1 in the field of microscopy.