2 micron femtosecond fiber laser

• US 8,792,158 B2
• Filed: 04/20/2012
• Issued: 07/29/2014
• Est. Priority Date: 04/20/2012
• Status: Expired due to Fees

• Current Assignee: Polaronyx, Inc.
• Original Assignee: Polaronyx, Inc.
• Inventors: Liu, Jian, Wan, Peng, Yang, Lihmei
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US13/452,817
• Publication Number:
  US 20130278997A1
• Time in Patent Office: 830 Days
• Field of Search: 359/333, 359/341.1, 359/337.5, 372/6
• US Class Current: 359/337.5
• CPC Class Codes: H01S 3/067 Fibre lasers
• 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 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/083 Ring lasers fibre ring lasers H01S3/06791
• CPC Class Codes: H01S 3/1112 Passive mode locking
• CPC Class Codes: H01S 3/1118 Semiconductor saturable absorbers, e.g. semiconductor saturable absorber mirrors [SESAMs]; Solid-state saturable absorbers, e.g. carbon nanotube [CNT] based
• CPC Class Codes: H01S 3/161 holmium
• CPC Class Codes: H01S 3/1616 thulium
• CPC Class Codes: H01S 3/1698 rare earth

Abstract

Methods and systems for generating femtosecond fiber laser pulses are disclose, including generating a signal laser pulse from a seed laser oscillator; using a first amplifier stage comprising an input and an output, wherein the signal laser pulse is coupled into the input of the first stage amplifier and the output of the first amplifier stage emits an amplified and stretched signal laser pulse; using an amplifier chain comprising an input and an output, wherein the amplified and stretched signal laser pulse from the output of the first amplifier stage is coupled into the input of the amplifier chain and the output of the amplifier chain emits a further amplified, stretched signal laser pulse. Other embodiments are described and claimed.

Claims

1. A fiber laser comprising:

a seed laser oscillator comprising an output, wherein the seed laser oscillator comprises a linear cavity or a ring cavity;

a first amplifier stage comprising;

an input and an output;

a spool of dispersion fiber comprising an input and an output, wherein the output of the seed laser oscillator is coupled to the input of the spool of dispersion fiber;

one or more pump diodes;

a signal/pump combiner comprising an input and an output, wherein the one or more pump diodes and the output of the spool of dispersion fiber are coupled to the input of the signal/pump combiner;

a gain fiber comprising a doped gain medium, an input, and an output, wherein the output of the signal/pump combiner is coupled to the input of the gain fiber; and

a polarization maintaining isolator comprising an input and an output, wherein the output of the gain fiber is coupled to the input of the polarization maintaining isolator and the output of the polarization maintaining isolator is configured to emit a stretched and amplified laser pulse;

wherein the output of the seed laser oscillator is coupled to the input of the first stage amplifier; and

an amplifier chain comprising;

an input and an output; and

one or more amplifier units comprising;

one or more pump diodes;

a signal/pump combiner comprising an input and an output, wherein the one or more pump diodes and the output of the first amplifier stage are coupled to the input of the signal/pump combiner;

a gain fiber comprising a doped gain medium, an input, and an output, wherein the output of the signal/pump combiner is coupled to the input of the gain fiber; and

a polarization maintaining isolator comprising an input and an output, wherein the output of the gain fiber is coupled to the input of the polarization maintaining isolator and the output of the polarization maintaining isolator is configured to emit an amplified laser pulse;

wherein the input of the amplifier chain is coupled to the output of the first amplifier stage and the output of the amplifier chain is configured to emit the amplified laser pulse.

2. The fiber laser of claim 1, wherein the amplified laser pulse has an energy ranging from 0.1 μ

J to 10 mJ.

3. The fiber laser of claim 1, wherein the amplified laser pulse has a wavelength ranging from 1850 nm to 2100 nm.

4. The fiber laser of claim 1, wherein the fiber laser further comprises a compressor comprising an input and an output, wherein the input of the compressor is coupled to the output of the amplifier chain and the compressor is configured for anomalous dispersion of the amplified laser pulse to emit a femtosecond laser pulse from the output of the compressor.

5. The fiber laser of claim 1, wherein the fiber laser further comprises a compressor comprising an input and an output, wherein the input of the compressor is coupled to the output of the amplifier chain and the compressor is configured for normal dispersion of the amplified laser pulse to emit a femtosecond laser pulse from the output of the compressor.

6. The fiber laser of claim 1, wherein the linear cavity comprises:

a fiber reflector;

a dispersion compensating fiber comprising an input and an output, wherein the fiber reflector is coupled to the input of the dispersion compensating fiber;

an output coupler comprising a first port, a second port, and an output, wherein the output of the dispersion compensating fiber is coupled to the first port of the output coupler;

one or more pump diodes;

a signal/pump combiner comprising an input and an output, wherein the one or more pump diodes and the second port of the output coupler are coupled to the input of the signal/pump combiner;

a gain fiber comprising a doped gain medium, an input, and an output, wherein the output of the signal/pump combiner is coupled to the input of the gain fiber;

a SESAM coupled to the output of the gain fiber;

a polarization maintaining isolator comprising an input and an output, wherein the output of the signal/pump combiner is coupled to the input of the polarization maintaining isolator and the output of the polarization maintaining isolator is configured to emit a signal laser pulse.

7. The fiber laser of claim 6, wherein the one or more pump diodes and the signal/pump combiner are multimode and the linear cavity further comprises a pump stripper coupled between the gain fiber and the SESAM.

8. The fiber laser of claim 6, wherein the signal laser pulse has a pulse repetition rate ranging from 100 kHz to 1,000 MHz.

9. The fiber laser of claim 6, wherein the one or more pump diodes have a wavelength ranging from 790 nm to 796 nm.

10. The fiber laser of claim 6, wherein the one or more pump diodes have a wavelength ranging from 1200 nm to 1220 nm.

11. The fiber laser of claim 6, wherein the one or more pump diodes have a wavelength ranging from 1570 nm to 1620 nm.

12. The fiber laser of claim 6, wherein the doped gain medium is at least one of:

Thulium, Holmium, and Thulium/Holmium.

13. The fiber laser of claim 6, wherein the gain fiber comprises a single cladding or a double cladding.

14. The fiber laser of claim 6, wherein the gain fiber comprises a core size ranging from 5 μ

m to 200 μ

m.

15. The fiber laser of claim 6, wherein the gain fiber comprises a numerical aperture ranging from 0.02 to 0.25.

16. The fiber laser of claim 1, wherein the ring cavity comprises:

one or more pump diodes;

a signal/pump combiner comprising an input and an output, wherein the one or more pump diodes are coupled to the input of the signal/pump combiner;

a gain fiber comprising a doped gain medium, an input, and an output, wherein the output of the signal/pump combiner is coupled to the input of the gain fiber;

an output coupler comprising a first port, a second port, and an output, wherein the output of the gain fiber is coupled to the first port of the output coupler and the output of the output coupler is configured to emit a signal laser pulse;

a first in line polarization controller comprising an input and an output, wherein the second port of the output coupler is coupled to the input of the first in line polarization controller;

an in line polarization isolator comprising an input and an output, wherein the output of the first in line polarization controller is coupled to the input of the in line polarization isolator;

a second in line polarization controller comprising an input and an output, wherein the output of the in line polarization isolator is coupled to the input of the second in line polarization controller; and

a dispersion compensating fiber comprising an input and an output, wherein the output of the second in line polarization controller is coupled to the input of the dispersion compensating fiber and the input of the signal/pump combiner is coupled to the output of the dispersion compensating fiber.

17. The fiber laser of claim 16, wherein the one or more pump diodes and the signal/pump combiner are multimode and the ring cavity further comprises a pump stripper coupled between the gain fiber and the output coupler.

18. The fiber laser of claim 16, wherein the one or more pump diodes have a wavelength ranging from 790 nm to 796 nm.

19. The fiber laser of claim 16, wherein the one or more pump diodes have a wavelength ranging from 1200 nm to 1220 nm.

20. The fiber laser of claim 16, wherein the one or more pump diodes have a wavelength ranging from 1570 nm to 1620 nm.

21. The fiber laser of claim 16, wherein the doped gain medium is at least one of:

Thulium, Holmium, and Thulium/Holmium.

22. The fiber laser of claim 16, wherein the gain fiber comprises a single cladding or a double cladding.

23. The fiber laser of claim 16, wherein the gain fiber comprises a core size ranging from 5 μ

m to 200 μ

m.

24. The fiber laser of claim 16, wherein the gain fiber comprises a numerical aperture ranging from 0.02 to 0.25.

25. The fiber laser of claim 1, wherein the one or more pump diodes of the first amplifier stage and the signal/pump combiner of the first amplifier stage are multimode and the first amplifier stage further comprises a pump stripper coupled between the gain fiber of the first amplifier stage and the polarization maintaining isolator of the first amplifier stage.

26. The fiber laser of claim 1, wherein the spool of dispersion fiber comprises normal dispersion fiber or anomalous dispersion fiber.

27. The fiber laser of claim 1, wherein the one or more pump diodes of the first amplifier stage have a wavelength ranging from 790 nm to 796 nm.

28. The fiber laser of claim 1, wherein the one or more pump diodes of the first amplifier stage have a wavelength ranging from 1200 nm to 1220 nm.

29. The fiber laser of claim 1, wherein the one or more pump diodes of the first amplifier stage have a wavelength ranging from 1570 nm to 1620 nm.

30. The fiber laser of claim 1, wherein the doped gain medium of the first amplifier stage is at least one of:

Thulium, Holmium, and Thulium/Holmium.

31. The fiber laser of claim 1, wherein the gain fiber of the first amplifier stage comprises a single cladding or a double cladding.

32. The fiber laser of claim 1 wherein the gain fiber of the first amplifier stage comprises a core size ranging from 5 μ

m to 200 μ

m.

33. The fiber laser of claim 1, wherein the gain fiber of the first amplifier stage comprises a numerical aperture ranging from 0.02 to 0.25.

34. The fiber laser of claim 1, wherein the one or more pump diodes of the amplifier chain and the signal/pump combiner of the amplifier chain are multimode and the one or more amplifier units further comprises a pump stripper coupled between the gain fiber of the amplifier chain and the polarization maintaining isolator of the amplifier chain.

35. The fiber laser of claim 1, wherein the one or more pump diodes of the amplifier chain have a wavelength ranging from 790 nm to 796 nm.

36. The fiber laser of claim 1, wherein the one or more pump diodes of the amplifier chain have a wavelength ranging from 1200 nm to 1220 nm.

37. The fiber laser of claim 1, wherein the one or more pump diodes of the amplifier chain have a wavelength ranging from 1570 nm to 1620 nm.

38. The fiber laser of claim 1, wherein the doped gain medium of the amplifier chain is at least one of:

Thulium, Holmium, and Thulium/Holmium.

39. The fiber laser of claim 1, wherein the gain fiber of the amplifier chain comprises a single cladding or a double cladding.

40. The fiber laser of claim 1, wherein the gain fiber of the amplifier chain comprises a core size ranging from 5 μ

m to 200 μ

m.

41. The fiber laser of claim 1, wherein the gain fiber of the amplifier chain comprises a numerical aperture ranging from 0.02 to 0.25.

42. A method for generating femtosecond fiber laser pulses, the method comprising:

generating a signal laser pulse from a seed laser oscillator, wherein the seed laser oscillator comprises a linear cavity or a ring cavity;

using a first amplifier stage comprising;

an input and an output;

a spool of dispersion fiber comprising an input and an output, wherein the output of the seed laser oscillator is coupled to the input of the spool of dispersion fiber;

one or more pump diodes;

a signal/pump combiner comprising an input and an output, wherein the one or more pump diodes and the output of the spool of dispersion fiber are coupled to the input of the signal/pump combiner;

a gain fiber comprising a doped gain medium, an input, and an output, wherein the output of the signal/pump combiner is coupled to the input of the gain fiber; and

a polarization maintaining isolator comprising an input and an output, wherein the output of the gain fiber is coupled to the input of the polarization maintaining isolator and the output of the polarization maintaining isolator is configured to emit an amplified and stretched signal laser pulse;

wherein the signal laser pulse is coupled into the input of the first stage amplifier and the output of the first amplifier stage emits the amplified and stretched signal laser pulse;

using an amplifier chain comprising;

an input and an output; and

one or more amplifier units comprising;

one or more pump diodes;

a signal/pump combiner comprising an input and an output, wherein the one or more pump diodes and the output of the first amplifier stage are coupled to the input of the signal/pump combiner;

a gain fiber comprising a doped gain medium, an input, and an output, wherein the output of the signal/pump combiner is coupled to the input of the gain fiber; and

a polarization maintaining isolator comprising an input and an output, wherein the output of the gain fiber is coupled to the input of the polarization maintaining isolator and the output of the polarization maintaining isolator is configured to emit a further amplified, stretched signal laser pulse;

wherein the amplified and stretched signal laser pulse from the output of the first amplifier stage is coupled into the input of the amplifier chain and the output of the amplifier chain emits the further amplified, stretched signal laser pulse.

43. The method of claim 42, wherein the further amplified, stretched signal laser pulse has an energy ranging from 0.1 μ

J to 10 mJ.

44. The method of claim 42, wherein the further amplified, stretched signal laser pulse has a wavelength ranging from 1850 nm to 2100 nm.

45. The method of claim 42, wherein the method further comprises:

using a compressor comprising an input and an output, wherein the input of the compressor is coupled to the output of the amplifier chain and the compressor is configured for anomalous dispersion of the further amplified, stretched signal laser pulse to emit a femtosecond laser pulse from the output of the compressor.

46. The method of claim 42, wherein the method further comprises:

using a compressor comprising an input and an output, wherein the input of the compressor is coupled to the output of the amplifier chain and the compressor is configured for normal dispersion of the further amplified, stretched signal laser pulse to emit a femtosecond laser pulse from the output of the compressor.

47. The method of claim 42, wherein the linear cavity comprises:

a fiber reflector;

a dispersion compensating fiber comprising an input and an output, wherein the fiber reflector is coupled to the input of the dispersion compensating fiber;

an output coupler comprising a first port, a second port, and an output, wherein the output of the dispersion compensating fiber is coupled to the first port of the output coupler;

one or more pump diodes;

a signal/pump combiner comprising an input and an output, wherein the one or more pump diodes and the second port of the output coupler are coupled to the input of the signal/pump combiner;

a gain fiber comprising a doped gain medium, an input, and an output, wherein the output of the signal/pump combiner is coupled to the input of the gain fiber;

a SESAM coupled to the output of the gain fiber;

a polarization maintaining isolator comprising an input and an output, wherein the output of the signal/pump combiner is coupled to the input of the polarization maintaining isolator and the output of the polarization maintaining isolator is configured to emit the signal laser pulse.

48. The method of claim 47, wherein the one or more pump diodes and the signal/pump combiner are multimode and the linear cavity further comprises a pump stripper coupled between the gain fiber and the SESAM.

49. The method of claim 47, wherein the signal laser pulse has a pulse repetition rate ranging from 100 kHz to 1,000 MHz.

50. The method of claim 47, wherein the one or more pump diodes have a wavelength ranging from 790 nm to 796 nm.

51. The method of claim 47, wherein the one or more pump diodes have a wavelength ranging from 1200 nm to 1220 nm.

52. The method of claim 47, wherein the one or more pump diodes have a wavelength ranging from 1570 nm to 1620 nm.

53. The method of claim 47, wherein the doped gain medium is at least one of:

Thulium, Holmium, and Thulium/Holmium.

54. The method of claim 47, wherein the gain fiber comprises a single cladding or a double cladding.

55. The method of claim 47, wherein the gain fiber comprises a core size ranging from 5 μ

m to 200 μ

m.

56. The method of claim 47, wherein the gain fiber comprises a numerical aperture ranging from 0.02 to 0.25.

57. The method of claim 42, wherein the ring cavity comprises:

one or more pump diodes;

a signal/pump combiner comprising an input and an output, wherein the one or more pump diodes are coupled to the input of the signal/pump combiner;

a gain fiber comprising a doped gain medium, an input, and an output, wherein the output of the signal/pump combiner is coupled to the input of the gain fiber;

an output coupler comprising a first port, a second port, and an output, wherein the output of the gain fiber is coupled to the first port of the output coupler and the output of the output coupler is configured to emit the signal laser pulse;

a first in line polarization controller comprising an input and an output, wherein the second port of the output coupler is coupled to the input of the first in line polarization controller;

an in line polarization isolator comprising an input and an output, wherein the output of the first in line polarization controller is coupled to the input of the in line polarization isolator;

a second in line polarization controller comprising an input and an output, wherein the output of the in line polarization isolator is coupled to the input of the second in line polarization controller; and

a dispersion compensating fiber comprising an input and an output, wherein the output of the second in line polarization controller is coupled to the input of the dispersion compensating fiber and the input of the signal/pump combiner is coupled to the output of the dispersion compensating fiber.

58. The method of claim 57, wherein the one or more pump diodes and the signal/pump combiner are multimode and the ring cavity further comprises a pump stripper coupled between the gain fiber and the output coupler.

59. The method of claim 57, wherein the one or more pump diodes have a wavelength ranging from 790 nm to 796 nm.

60. The method of claim 57, wherein the one or more pump diodes have a wavelength ranging from 1200 nm to 1220 nm.

61. The method of claim 57, wherein the one or more pump diodes have a wavelength ranging from 1570 nm to 1620 nm.

62. The method of claim 57, wherein the doped gain medium is at least one of:

Thulium, Holmium, and Thulium/Holmium.

63. The method of claim 57, wherein the gain fiber comprises a single cladding or a double cladding.

64. The method of claim 57, wherein the gain fiber comprises a core size ranging from 5 μ

m to 200 μ

m.

65. The method of claim 57, wherein the gain fiber comprises a numerical aperture ranging from 0.02 to 0.25.

66. The method of claim 42, wherein the one or more pump diodes of the first amplifier stage and the signal/pump combiner of the first amplifier stage are multimode and the first amplifier stage further comprises a pump stripper coupled between the gain fiber of the first amplifier stage and the polarization maintaining isolator of the first amplifier stage.

67. The method of claim 42, wherein the spool of dispersion fiber comprises normal dispersion fiber or anomalous dispersion fiber.

68. The method of claim 42, wherein the one or more pump diodes of the first amplifier stage have a wavelength ranging from 790 nm to 796 nm.

69. The method of claim 42, wherein the one or more pump diodes of the first amplifier stage have a wavelength ranging from 1200 nm to 1220 nm.

70. The method of claim 42, wherein the one or more pump diodes of the first amplifier stage have a wavelength ranging from 1570 nm to 1620 nm.

71. The method of claim 42, wherein the doped gain medium of the first amplifier stage is at least one of:

Thulium, Holmium, and Thulium/Holmium.

72. The method of claim 42, wherein the gain fiber of the first amplifier stage comprises a single cladding or a double cladding.

73. The method of claim 42, wherein the gain fiber of the first amplifier stage comprises a core size ranging from 5 μ

m to 200 μ

m.

74. The method of claim 42, wherein the gain fiber of the first amplifier stage comprises a numerical aperture ranging from 0.02 to 0.25.

75. The method of claim 42, wherein the one or more pump diodes of the amplifier chain and the signal/pump combiner of the amplifier chain are multimode and the one or more amplifier units further comprises a pump stripper coupled between the gain fiber of the amplifier chain and the polarization maintaining isolator of the amplifier chain.

76. The method of claim 42, wherein the one or more pump diodes of the amplifier chain have a wavelength ranging from 790 nm to 796 nm.

77. The method of claim 42, wherein the one or more pump diodes of the amplifier chain have a wavelength ranging from 1200 nm to 1220 nm.

78. The method of claim 42, wherein the one or more pump diodes of the amplifier chain have a wavelength ranging from 1570 nm to 1620 nm.

79. The method of claim 42, wherein the doped gain medium of the amplifier chain is at least one of:

Thulium, Holmium, and Thulium/Holmium.

80. The method of claim 42, wherein the gain fiber of the amplifier chain comprises a single cladding or a double cladding.

81. The method of claim 42, wherein the gain fiber of the amplifier chain comprises a core size ranging from 5 μ

m to 200 μ

m.

82. The method of claim 42, wherein the gain fiber of the amplifier chain comprises a numerical aperture ranging from 0.02 to 0.25.