Laser based frequency standards and their applications

• US 20070086713A1
• Filed: 10/13/2006
• Published: 04/19/2007
• Est. Priority Date: 10/17/2005
• Status: Active Grant

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Fermann, Martin, Ingmar, Hartl
• Granted Patent: US 7,809,222 B2
• Time in Patent Office: Days
• 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 supercontinuum source comprising;

a source of short equidistantly spaced optical pulses,

a highly nonlinear waveguide based on crystalline material.

2. A supercontinuum source according to claim 1,

wherein said crystalline material is a periodically poled crystalline material.

3. A supercontinuum source according to claim 2,

wherein said periodically poled crystalline material is based on LiNbO₃.

4. A supercontinuum source according to claim 1,

wherein said crystalline material is selected from LiNbO₃, silicon or a semiconductor material.

5. A supercontinuum source according to claim 1,

said supercontinuum source further comprising a passively modelocked laser;

an amplifier for amplifying an output from said modelocked laser, said amplified output being injected into said highly nonlinear crystalline waveguide.

6. A supercontinuum source according to claim 5,

wherein said amplifier is a waveguide amplifier.

7. A supercontinuum source according to claim 1,

said supercontinuum source further comprising a

passively modelocked fiber laser.

8. A supercontinuum source according to claim 7, wherein said passively modelocked fiber laser is configured to operate at a repetition rate>

20 MHz.

9. A passively modelocked fiber laser according to claim 7,

wherein said passively modelocked fiber laser is configured to operate at a repetition rate>

300 MHz.

10. 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.

12. A frequency comb source according to claim 10,

further comprising means for stabilizing a carrier envelope offset frequency related to said frequency comb, using said continuum.

13. A frequency comb source according to claim 10, wherein said waveguide oscillator further contains at least one of Er Bi-fiber and Bi-fiber.

14. A frequency comb source according to claim 10, wherein

said passively modelocked waveguide oscillator further includes means to stabilize the pulse repetition rate related to said oscillator.

15. A frequency comb source according to claim 10, wherein

said frequency comb source comprises a part of an optical wave meter.

16. A frequency comb source according to claim 10, wherein

said frequency comb source comprises a part of an optical clock.

17. A frequency comb source according to claim 10,

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.

11. 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,

said waveguide oscillator operating at a repetition rate>

250 MHz.

18. A frequency comb source according to claim 11, wherein

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

19. A modelocked fiber laser, producing pulses with a peak pulse power,

said modelocked fiber laser configured to provide an output of equidistant optical pulses at a certain repetition frequency, said modelocked fiber laser further containing means for adjusting the absolute phase of said optical pulses, said repetition frequency and said pulse phase further being matched to an external cavity, such that the pulse peak power within the boundaries of said external cavity is substantially higher compared to the pulse peak power provided by said modelocked fiber laser.

20. A modelocked fiber laser according to claim 19, said modelocked fiber laser further being amplified in a chirped pulse amplification system.

21. A modelocked fiber laser according to claim 19, said absolute phase control being adjustable to produce an individual laser comb linewidth which is smaller than the linewidth of the individual comb lines comprising the frequency comb spectrum of the enhancement cavity, and wherein the fiber laser frequency comb is adjusted to overlap with the frequency comb spectrum of the enhancement cavity, and wherein the comb spacing of the fiber laser comb spectrum is adjusted to be equal to the comb spacing of the comb spectrum of the enhancement cavity.

22. A laser system according to claim 20, where said laser system is further used to generate VUV, EUV and THz radiation in said enhancement cavity via the insertion of a nonlinear material into said enhancement cavity.

23. A laser system according to claim 20, where said nonlinear material is a gas, a liquid or a solid.

36. A laser system according to claim 20, where said nonlinear material is used as a parametric amplifier.

24. 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.

29. A source of phase stable optical pulses according to claim 24,

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

25. 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.

26. A source of equidistant optical pulses according to claim 25,

said source comprising a part of an optical analogue to digital converter.

27. A source of equidistant optical pulses according to claim 25,

said source comprising a part of an optical sampling oscilloscope.

28. A source of phase stable optical pulses, comprising:

a modelocked fiber laser,

an output of said modelocked fiber laser being amplified in a fiber amplifier;

a stable phase being obtained at the output of said fiber amplifier

30. A fiber link for the transmission or distribution of frequency and time standards comprising

a frequency comb source,

an array of carrier envelope stabilized lasers, separated by path-length controlled fiber transmission lines.

31. A fiber link according to claim 30,

said path-length control comprising electronic feedback loops.

32. A source of phase-stable optical pulses, comprising;

an array individual outputs;

said outputs configured to tile a plane,

a modelocked fiber laser,

said modelocked fiber laser being amplified in an array of individual fiber amplifiers;

said individual amplifiers being configured to produce said individual outputs;

a means to stabilize the phase of said individual amplifiers

said stable phase being obtained at the output of said fiber amplifier array,

said stable phase being characterized in that the relative phase fluctuations between individual amplifiers is smaller than 1 rad.

33. A source of phase-stable optical pulses comprising an array of individual outputs according to claim 32, wherein a relative phase of said individual output being controlled to smaller than 0.1 rad.

34. A source of phase-stable optical pulses according to claim 32, wherein

said individual amplifiers are constructed from multi-core fibers.

35. A source of phase-stable optical pulses according to claim 32, further comprising individual phase-adjusters operating on each, but one of said individual amplifiers and an electronic control loop to lock the phase of said each but one individual amplifiers to the remaining individual amplifier, which is used as a reference for the electronic control loop.