Pulsed laser sources

• US 9,401,579 B2
• Filed: 11/26/2013
• Issued: 07/26/2016
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Fermann, Martin E., Hartl, Ingmar, Imeshev, Gennady
• Primary Examiner(s): Sanghavi, Hemang
• Application Number:
  US14/090,374
• Publication Number:
  US 20140233089A1
• Time in Patent Office: 973 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G02F 1/3517 using an interferometer
• CPC Class Codes: G02F 1/3528 for producing a supercontinuum
• CPC Class Codes: H01S 3/0014 Monitoring arrangements not otherwise provided for photometry G01J1/00, e.g. G01J1/4257; radiation pyrometry G01J5/00; measuring coherence of light G01J9/00; measuring wavelength of light G01J9/00, e.g. G01J9/0246; measuring optical pulses G01J11/00; calorimetrically measuring power of laser beams G01K17/003
• 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 3/0078 Frequency filtering
• 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 3/067 Fibre lasers
• CPC Class Codes: H01S 3/0675 Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/094042 of a fibre laser
• CPC Class Codes: H01S 3/10 Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
• CPC Class Codes: H01S 3/105 by controlling the mutual position or the reflecting properties of the reflectors of the cavity , e.g. by controlling the cavity lengthH01S3/10076, H01S3/13 take precedence
• CPC Class Codes: H01S 3/1053 Control by pressure or deformation
• CPC Class Codes: H01S 3/106 by controlling devices placed within the cavity H01S3/10076, H01S3/13 take precedence
• CPC Class Codes: H01S 3/1067 using pressure or deformation
• CPC Class Codes: H01S 3/109 Frequency multiplication, e.g. harmonic generation
• CPC Class Codes: H01S 3/1106 Mode locking
• CPC Class Codes: H01S 3/1118 Semiconductor saturable absorbers, e.g. semiconductor saturable absorber mirrors [SESAMs]; Solid-state saturable absorbers, e.g. carbon nanotube [CNT] based
• CPC Class Codes: H01S 3/1616 thulium

Abstract

Modelocked fiber laser resonators may be coupled with optical amplifiers. An isolator optionally may separate the resonator from the amplifier. A reflective optical element on one end of the resonator having a relatively low reflectivity may be employed to couple light from the resonator to the amplifier. Enhanced pulse-width control may be provided with concatenated sections of both polarization-maintaining and non-polarization-maintaining fibers. Apodized fiber Bragg gratings and integrated fiber polarizers may also be included in the laser cavity to assist in linearly polarizing the output of the cavity. Very short pulses with a large optical bandwidth may be obtained by matching the dispersion value of the grating to the inverse of the dispersion of the intra-cavity fiber. Frequency comb sources may be constructed from such modelocked fiber oscillators. Low dispersion and an in-line interferometer that provides feedback may assist in controlling the frequency components output from the comb source.

Claims

1. A fiber based frequency comb source for generating a frequency comb, said fiber based frequency comb source comprising:

a mode locked fiber oscillator comprising at least one cavity element based on polarization maintaining fiber;

at least one fiber amplifier; and

at least one highly nonlinear fiber optically connected to said mode locked fiber oscillator, said at least one highly nonlinear fiber configured to generate a coherent supercontinuum used to stabilize a carrier envelope offset frequency related to said frequency comb.

2. The fiber based frequency comb source according to claim 1, said mode locked fiber oscillator comprising at least one Faraday rotator.

3. The fiber based frequency comb source according to claim 1, said at least one fiber amplifier being polarization maintaining.

4. The fiber based frequency comb source according to claim 1, said at least one highly nonlinear fiber being polarization maintaining.

5. The fiber based frequency comb source according to claim 1, said mode locked fiber oscillator producing an output with an environmentally stable polarization output state.

6. The fiber based frequency comb source according to claim 1, said at least one fiber amplifier configured to be nonlinear.

7. The fiber based frequency comb source according to claim 1, said at least one fiber amplifier configured to spectrally broaden a spectrum of said mode locked fiber oscillator.

8. The fiber based frequency comb source according to claim 1, said mode locked fiber oscillator comprising a saturable absorber.

9. The fiber based frequency comb source according to claim 1, further comprising a one-arm f-2f interferometer.

10. The fiber based frequency comb source according to claim 1, further comprising:

a bi-directional optical path between said mode locked fiber oscillator and said at least one fiber amplifier, arranged such that light from said mode locked fiber oscillator can propagate to said at least one fiber amplifier and light from said at least one fiber amplifier can propagate to said mode locked fiber oscillator,

wherein at least one of said mode locked fiber oscillator or said at least one fiber amplifier comprises a polarization maintaining component.

11. A fiber based frequency comb source for generating a frequency comb, said fiber frequency comb source comprising:

a mode locked fiber oscillator configured to produce an oscillator output with an environmentally stable polarization oscillator output state;

a nonlinear fiber amplifier configured to accept an input with an environmentally stable polarization state and produce an amplifier output with an environmentally stable polarization amplifier output state, said nonlinear fiber amplifier configured to broaden a spectrum of said mode locked fiber oscillator;

a compressor configured to produce pulses having pulse widths shorter than approximately 200 fs; and

a polarization maintaining highly nonlinear fiber disposed downstream from said compressor,

wherein said polarization maintaining highly nonlinear fiber is configured to generate a coherent supercontinuum, and wherein compressed pulses having said pulse widths preserve the coherence of said supercontinuum.

12. The fiber based frequency comb source according to claim 11, said coherent supercontinuum used to stabilize a carrier envelope offset frequency related to said frequency comb.

13. The fiber based frequency comb source according to claim 11, said mode locked fiber oscillator comprising a saturable absorber.

14. The fiber based frequency comb source according to claim 11, further comprising a one-arm f-2f interferometer.

15. The fiber frequency comb source according to claim 11, further comprising:

a bi-directional optical path between said mode locked fiber oscillator and said nonlinear fiber amplifier, arranged such that light from said mode locked fiber oscillator can propagate to said nonlinear fiber amplifier and light from said nonlinear fiber amplifier can propagate to said mode locked fiber oscillator,

wherein at least one of said mode locked fiber oscillator or said nonlinear fiber amplifier comprises a polarization maintaining component.

16. A fiber based frequency comb source for generating a frequency comb, said fiber based frequency comb source comprising:

a mode locked fiber laser;

a cladding pumped fiber amplifier;

a highly nonlinear fiber configured to generate a supercontinuum; and

a bi-directional optical path between said mode locked fiber laser and said cladding pumped fiber amplifier arranged such that light from said mode locked fiber laser can propagate to said cladding pumped fiber amplifier and light from said cladding pumped fiber amplifier can propagate to said mode locked fiber laser,

wherein at least one of said mode locked fiber laser or said cladding pumped fiber amplifier comprises a polarization maintaining component.

17. The fiber frequency comb source according to claim 16, said highly nonlinear fiber being polarization maintaining.

18. The fiber frequency comb source according to claim 16, said highly nonlinear fiber configured to generate a coherent supercontinuum.

19. The fiber frequency comb source according to claim 18, wherein said coherent supercontinuum is used to measure a carrier envelope offset frequency related to said frequency comb.

20. The fiber based frequency comb source according to claim 16, said modelocked fiber laser comprising a saturable absorber.

21. The fiber frequency comb source according to claim 16, further comprising a one-arm f-2f interferometer.