Laser based frequency standards and their applications

• US 7,809,222 B2
• Filed: 10/13/2006
• Issued: 10/05/2010
• Est. Priority Date: 10/17/2005
• Status: Active Grant

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Hartl, Ingmar, Fermann, Martin
• Primary Examiner(s): Peng; Charlie
• Assistant Examiner(s): BLEVINS, JERRY M
• Application Number:
  US11/546,998
• Publication Number:
  US 20070086713A1
• Time in Patent Office: 1,453 Days
• Field of Search: 385/122, 385/14, 385/15, 385/27
• US Class Current: 385/122
• CPC Class Codes: G02F 1/3528 for producing a supercontinuum
• CPC Class Codes: G02F 1/3558 Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM]
• CPC Class Codes: G02F 1/365 in an optical waveguide structure G02F1/377, G02F1/395 take precedence
• CPC Class Codes: G02F 2203/56 Frequency comb synthesizer
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 3/067 Fibre lasers
• CPC Class Codes: H01S 3/06716 Fibre compositions per se C03C13/04or doping with active elements lasing materials in general H01S3/14
• CPC Class Codes: H01S 3/1112 Passive mode locking

Abstract

Frequency standards based on mode-locked fiber lasers, fiber amplifiers and fiber-based ultra-broad bandwidth light sources, and applications of the same.

Claims

1. A frequency comb source, comprising:

a passively modelocked waveguide oscillator;

at least one highly nonlinear waveguide connected to said oscillator, characterized in that a coherent supercontinuum is generated by said highly nonlinear waveguide, and

wherein said waveguide oscillator operates at a repetition rate >

110 MHz; and

means for stabilizing a carrier envelope offset frequency related to said frequency comb.

2. A frequency comb source according to claim 1,

a passively modelocked waveguide oscillator;

at least one highly nonlinear waveguide connected to said oscillator, characterized in that a coherent supercontinuum is generated by said highly nonlinear waveguide,

wherein said waveguide oscillator operates at a repetition rate >

250 MHz.

3. A laser system according to claim 2, wherein said passively modelocked waveguide oscillator and said at least one highly nonlinear waveguide each comprise a length of optical fiber, and said oscillator and said at least one non-linear waveguide are connected with fiber splices.

4. A laser system according to claim 2, further comprising an optical amplifier between said oscillator and said at least one non-linear waveguide.

5. A frequency comb source according to claim 1, wherein said waveguide oscillator further contains at least one of Er Bi-fiber and Bi-fiber.

6. A frequency comb source according to claim 1, wherein said passively modelocked waveguide oscillator further includes means to stabilize the pulse repetition rate related to said oscillator.

7. A frequency comb source according to claim 1, wherein said frequency comb source comprises a part of an optical wave meter.

8. A frequency comb source according to claim 1, wherein said frequency comb source comprises a part of an optical clock.

9. A frequency comb source according to claim 1, said frequency comb source being further configured to provide an output of equidistant optical pulses, said frequency comb source further containing means to stabilize the absolute phase of said optical pulses, thus producing a pulse train of equidistant optical pulses with fixed optical phase.

10. A laser system according to claim 1, wherein said passively modelocked waveguide oscillator and said at least one highly nonlinear waveguide each comprise a length of optical fiber, and said oscillator and said at least one non-linear waveguide are connected with fiber splices.

11. A laser system according to claim 1, further comprising an optical amplifier between said oscillator and said at least one non-linear waveguide.

12. A frequency comb source according to claim 1, wherein said means for stabilizing said carrier envelope offset frequency is configured to utilize said continuum.

13. A frequency comb source according to claim 12, wherein said means for stabilizing comprises a feedback loop controlling said passively modelocked waveguide oscillator based on a control signal derived from an output of said highly nonlinear waveguide.

14. A frequency comb source according to claim 1, wherein said passively mode waveguide oscillator is diode pumped, said oscillator comprising at least one of a saturable absorber and an intra-cavity fiber Bragg grating, and wherein said means for stabilizing comprises a feedback system to regulate at least one of an oscillator pump power, a fiber Bragg grating temperature, a fiber Bragg grating stress and a saturable absorber temperature.

15. A frequency comb source according to claim 1, wherein said frequency comb source is configured to produce a spectral output downstream of said oscillator, and said means for stabilizing said carrier envelope offset frequency comprises at least one passive external cavity.

16. A frequency comb source according to claim 1, wherein said frequency comb source is configured to produce a spectral output downstream of said oscillator, and said means for stabilizing said carrier envelope offset frequency comprises at least two feedback loops configured with detectors for receiving two separate narrow spectral portions of said spectral output.

17. A frequency comb source according to claim 16, further comprising a reference cavity, and wherein said at least two feedback loops are configured to align said carrier envelope offset frequency and the repetition rate of said oscillator to said reference cavity.

18. A frequency comb source according to claim 1, comprising first and a second frequency comb lasers, and wherein said means for stabilizing said carrier envelope offset frequency is configured to lock said carrier envelope offset frequency to said second frequency comb laser.

19. A frequency comb source according to claim 1, comprising first and second frequency comb lasers, and wherein said second frequency comb laser is configured with a second carrier envelope offset frequency and a feedback loop to stabilize the difference of two said carrier envelope offset frequencies.

20. A frequency comb source according to claim 1, wherein said source comprises an external cavity, said passively mode locked oscillator being matched in phase and repetition rate to said external optical cavity.

21. A frequency comb source, comprising:

a passively modelocked oscillator;

at least one highly nonlinear waveguide connected to said oscillator, characterized in that a coherent supercontinuum is generated by said highly nonlinear waveguide,

said highly nonlinear waveguide further containing at least one segment where frequency converted light is generated,

said frequency converted light generating a beat signal in a spectral range within said coherent supercontinuum,

said beat signal being applied to stabilize a carrier envelope phase of said oscillator.

22. A source of phase stable optical pulses according to claim 21,

said phase-stable source being further matched in phase and repetition rate to an external optical cavity.

23. A source of phase stable optical pulses according to claim 21, further comprising an optical amplifier between said oscillator and said at least one non-linear waveguide.

24. A low timing jitter source of equidistant optical pulses, comprising:

a passively modelocked waveguide oscillator,

said waveguide oscillator further containing a saturable absorber element;

said saturable absorber comprising a means for inducing modelocking in said oscillator,

said waveguide oscillator being constructed from an optical cavity with a certain dispersion;

said optical cavity containing a number of cavity components;

said dispersion of said optical cavity being substantially lower than the dispersion of each of the cavity components,

said oscillator further configured to operate at a repetition rate >

110 MHz.

25. A source of equidistant optical pulses according to claim 24, said source comprising a part of an optical analogue to digital converter.

26. A source of equidistant optical pulses according to claim 24, said source comprising a part of an optical sampling oscilloscope.

27. A low timing jitter source according to claim 24, wherein said passively modelocked waveguide oscillator further includes means to stabilize the carrier envelope offset frequency of said pulses.

28. A low timing jitter source according to claim 24, wherein said passively modelocked waveguide oscillator further includes means to stabilize the pulse repetition rate related to said oscillator.

29. A low timing jitter source according to claim 24, wherein said passively modelocked waveguide oscillator is matched in phase and repetition rate to an external cavity.

30. A low timing jitter source according to claim 29, said external cavity further incorporating a nonlinear element such as a crystal or a gas.

31. A frequency comb source, comprising:

a passively modelocked waveguide oscillator;

at least one highly nonlinear waveguide connected to said oscillator, characterized in that a coherent supercontinuum is generated by said highly nonlinear waveguide, and said waveguide oscillator operates at a repetition rate >

250 MHz;

wherein

said frequency comb source comprises a part of an optical analogue to digital converter.