Source of optical pulses

• US 8,902,496 B2
• Filed: 03/12/2013
• Issued: 12/02/2014
• Est. Priority Date: 01/20/2006
• Status: Active Grant

• Current Assignee: NKT Photonics A/S (Hamamatsu Photonics KK)
• Original Assignee: Fianium Ltd (Hamamatsu Photonics KK)
• Inventors: Clowes, John Redvers, Grudinin, Anatoly Borisovich, Godfrey, Ian Michael, Vysniauskas, Kestutis
• Primary Examiner(s): Diacou, Ari M
• Application Number:
  US13/797,640
• Publication Number:
  US 20140104677A1
• Time in Patent Office: 630 Days
• Field of Search: 359/346, 359/341.32, 359/341.33, 359/341.5, 372/6
• US Class Current: 359/346
• CPC Class Codes: G02F 1/383 of the optical fibre type
• CPC Class Codes: H01S 2301/03 Suppression of nonlinear conversion, e.g. specific design to suppress for example stimulated brillouin scattering [SBS], mainly in optical fibres in combination with multimode pumping
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108
• CPC Class Codes: H01S 3/0064 Anti-reflection devices, e.g. optical isolaters absorbing layers for marking or protecting purposes in laser working B23K26/50; magneto-optical non-reciprocal devices G02F1/093, G02F1/0955
• CPC Class Codes: H01S 3/0092 Nonlinear frequency conversion, e.g. second harmonic generation [SHG] or sum- or difference-frequency generation outside the laser cavity nonlinear frequency conversion per se G02F1/35
• CPC Class Codes: H01S 3/061 with elliptical or circular cross-section and elongated shape, e.g. rod
• CPC Class Codes: H01S 3/067 Fibre lasers
• CPC Class Codes: H01S 3/06712 Polarising fibre; Polariser
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• CPC Class Codes: H01S 3/109 Frequency multiplication, e.g. harmonic generation
• CPC Class Codes: H01S 3/1106 Mode locking
• CPC Class Codes: H01S 3/1618 ytterbium
• CPC Class Codes: H01S 3/2308 Amplifier arrangements, e.g. MOPA
• CPC Class Codes: H01S 3/2316 Cascaded amplifiers
• CPC Class Codes: H01S 3/2375 Hybrid lasers H01S3/07 takes precedence

Abstract

The invention can include an apparatus for producing optical pulses, comprising an oscillator for producing optical pulses at a first optical pulse repetition frequency, the optical pulses having a first frequency of light; a pulse picker for receiving optical pulses having the first optical pulse repetition frequency and operable to reduce the optical pulse repetition frequency to produce optical pulses having the first frequency and a reduced optical pulse repetition frequency that is less than the first optical pulse repetition frequency; an optical fiber receiving optical pulses having the reduced optical pulse repetition frequency and first frequency, to nonlinearly produce light that includes a frequency that is twice the first frequency; and an Ytterbium doped fiber amplifier in optical communication with the pulse picker and the optical fiber and located between the pulse picker and the oscillator.

Claims

1. Apparatus for producing short optical pulses, comprising:

an oscillator for producing optical pulses at a first optical pulse repetition frequency, the optical pulses having a first frequency of light;

a pulse picker for receiving optical pulses having the first optical pulse repetition frequency and operable to reduce the optical pulse repetition frequency to produce optical pulses having the first frequency of light and a reduced optical pulse repetition frequency that is less than the first optical pulse repetition frequency;

an optical fiber receiving optical pulses having the reduced optical pulse repetition frequency and first frequency of light, to nonlinearly produce light that includes a frequency of light that is twice the first frequency of light;

an Ytterbium doped fiber amplifier in optical communication with said pulse picker and said optical fiber and located between the pulse picker and the oscillator; and

a nonlinear optical crystal.

2. The apparatus of claim 1 comprising an Ytterbium doped fiber amplifier located after the pulse picker.

3. The apparatus of claim 1 wherein said pulse picker comprises an acousto optic modulator driven at a synchronized gating frequency lower than the first optical pulse repetition frequency of the oscillator.

4. The apparatus of claim 1 wherein said optical pulses produced by said oscillator have a first time duration and wherein said optical pulses received by said optical fiber and having the reduced optical pulse repetition frequency and first frequency of light furthermore comprise the first time duration.

5. The apparatus of claim 1 wherein said oscillator comprises a modelocked fiber oscillator.

17. The apparatus of claim 1 wherein said nonlinear optical crystal produces optical pulses comprising ultraviolet light.

18. The apparatus of claim 4 wherein said nonlinear optical crystal produces optical pulses comprising ultraviolet light.

6. Method of producing short optical pulses, comprising:

producing optical pulses at a first optical pulse repetition frequency, the optical pulses having a first frequency of light;

amplifying with a Ytterbium doped amplifier the produced optical pulses having the first optical pulse repetition frequency and the first frequency of light;

subsequent to amplifying, pulse picking amplified optical pulses having the first optical pulse repetition frequency and the first frequency of light to produce optical pulses having the first frequency of light and a reduced optical pulse repetition frequency that is less than the first optical pulse repetition frequency;

nonlinearly producing, from optical pulses having the first frequency of light and the reduced optical pulse repetition frequency, optical pulses having the reduced optical pulse repetition frequency and that include a nonlinearly produced second frequency of light that is twice the first frequency of light; and

further nonlinearly producing optical pulses from the nonlinearly produced optical pulses.

7. The method of claim 6 comprising amplifying, after the step of pulse picking and before the step of nonlinearly producing, the optical pulses having the reduced optical pulse repetition frequency and the first frequency of light.

8. The method of claim 6 comprising separating a desired wavelength from another wavelength and transmitting the desired wavelength.

9. The method of claim 7 comprising separating a desired wavelength from another wavelength and transmitting the desired wavelength.

10. The method of claim 6 wherein producing the optical pulses at a first optical pulse repetition frequency and having a first frequency of light comprises producing the optical pulses so as to have a first time duration;

and

wherein nonlinearly producing comprises nonlinearly producing from optical pulses having the first time duration as well as the first frequency and the reduced optical pulse repetition frequency.

11. The method of claim 6 wherein nonlinearly producing comprises nonlinearly producing with an optical fiber that receives the pulses having the first frequency of light and the reduced optical pulse repetition frequency.

12. The method of claim 11 wherein further nonlinearly producing comprises producing optical pulses with an optical crystal.

13. The method of claim 12 wherein further nonlinearly producing optical pulses comprises producing optical pulses comprising ultraviolet light.

14. The method of claim 6 wherein further nonlinearly producing comprises producing optical pulses with an optical crystal.

15. The method of claim 14 wherein further nonlinearly producing optical pulses comprises producing optical pulses comprising ultraviolet light.

16. The method of claim 6 wherein further nonlinearly producing optical pulses comprises producing optical pulses comprising ultraviolet light.

19. Apparatus for producing short optical pulses, comprising:

an oscillator for producing optical pulses at a first optical pulse repetition frequency, the optical pulses having a first wavelength and a first time duration;

a pulse picker for receiving optical pulses having the first optical pulse repetition frequency, first wavelength and first time duration and operable to reduce the optical pulse repetition frequency to produce optical pulses having the first wavelength, first time duration and a reduced optical pulse repetition frequency that is less than the first optical pulse repetition frequency;

an optical fiber receiving optical pulses at the reduced optical pulse repetition frequency and having the first wavelength and first time duration to produce, at the reduced optical pulse frequency, optical pulses that include one or more nonlinearly produced wavelengths different than the first wavelength; and

a nonlinear optical crystal.

20. The apparatus of claim 19 comprising an Ytterbium doped fiber amplifier located before the pulse picker for amplifying optical pulses having the first wavelength and time duration at the first optical pulse repetition frequency.

21. The apparatus of claim 19 comprising an Ytterbium doped fiber amplifier located after the pulse picker for amplifying optical pulses having the first wavelength and the first time duration at the reduced optical pulse repetition frequency.

22. The apparatus of claim 19 wherein said pulse picker comprises an acousto optic modulator driven at a synchronized gating frequency lower than first optical pulse repetition frequency of the oscillator.

23. The apparatus of claim 19 wherein said oscillator comprises a modelocked fiber oscillator.

24. The apparatus of claim 19 wherein said nonlinear optical crystal produces optical pulses comprising ultraviolet light.

25. Method of producing short optical pulses, comprising:

producing optical pulses at a first optical pulse repetition frequency, the optical pulses having a first wavelength and a first time duration;

pulse picking optical pulses having the first optical pulse repetition frequency, the first wavelength and first time duration to produce optical pulses having the first wavelength and first time duration and a reduced optical pulse repetition frequency that is less than the first optical pulse repetition frequency;

nonlinearly producing, from optical pulses having the first wavelength, first time duration and the reduced optical pulse repetition frequency, optical pulses having the reduced optical pulse repetition frequency and including one or more nonlinearly produced wavelengths different from the first wavelength; and

further nonlinearly producing optical pulses from the nonlinearly produced optical pulses.

26. The method of claim 25 wherein nonlinearly producing comprises nonlinearly producing with an optical fiber.

27. The method of claim 26 wherein further nonlinearly producing comprises producing optical pulses with an optical crystal.

28. The method of claim 27 wherein further nonlinearly producing optical pulses comprises producing optical pulses comprising ultraviolet light.

29. The method of claim 25 wherein further nonlinearly producing comprises producing optical pulses with an optical crystal.

30. The method of claim 29 wherein further nonlinearly producing optical pulses comprises producing optical pulses comprising ultraviolet light.

31. The method of claim 25 wherein further nonlinearly producing optical pulses comprises producing optical pulses comprising ultraviolet light.

32. The method of claim 25, comprising amplifying, prior to the step of pulse picking, the optical pulses having the first optical pulse repetition frequency, the first time duration and the first wavelength.

33. The method of claim 25, comprising amplifying, after the step of pulse picking, the optical pulses having the reduced optical pulse repetition frequency, the first time duration and the first wavelength.

34. The method of claim 25 wherein the one or more wavelengths different from the first wavelength comprises a wavelength that is shorter than the first wavelength.

35. The method of claim 34 wherein the first wavelength has a corresponding frequency and wherein the wavelength that is shorter than the first wavelength has a corresponding frequency that is twice the frequency that corresponds to the first wavelength.

36. The method of claim 25 comprising separating a desired wavelength of the one or more wavelengths from another wavelength and transmitting light having the desired wavelength as the output of the optical pulse source.