Utilization of Yb: and Nd: mode-locked oscillators in solid-state short pulse laser systems

• US 8,773,754 B2
• Filed: 03/22/2011
• Issued: 07/08/2014
• Est. Priority Date: 05/23/2000
• Status: Expired due to Term

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Harter, Donald J., Cho, Gyu C., Fermann, Martin E., Hartl, Ingmar
• Primary Examiner(s): BOLDA, ERIC L
• Application Number:
  US13/053,600
• Publication Number:
  US 20110200061A1
• Time in Patent Office: 1,204 Days
• Field of Search: 359/337.2, 359/341.1, 359/348, 372/25
• US Class Current: 359/337.2
• 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 3/0078 Frequency filtering
• CPC Class Codes: H01S 3/0085 Modulating the output, i.e. the laser beam is modulated outside the laser cavity
• 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 3/10023 by functional association of additional optical elements, e.g. filters, gratings, reflectors
• CPC Class Codes: H01S 3/109 Frequency multiplication, e.g. harmonic generation
• CPC Class Codes: H01S 3/1616 thulium
• CPC Class Codes: H01S 3/1618 ytterbium
• CPC Class Codes: H01S 3/1643 YAG
• CPC Class Codes: H01S 3/235 Regenerative amplifiers
• CPC Class Codes: H01S 5/5045 the arrangement having a frequency filtering function

Abstract

An optimized Yb: doped fiber mode-locked oscillator and fiber amplifier system for seeding Nd: or Yb: doped regenerative amplifiers. The pulses are generated in the Yb: or Nd: doped fiber mode-locked oscillator, and may undergo spectral narrowing or broadening, wavelength converting, temporal pulse compression or stretching, pulse attenuation and/or lowering the repetition rate of the pulse train. The conditioned pulses are subsequently coupled into an Yb: or Nd: fiber amplifier. The amplified pulses are stretched before amplification in the regenerative amplifier that is based on an Nd: or Yb: doped solid-state laser material, and then recompressed for output.

Claims

1. A laser apparatus, comprising:

a laser pulse source comprising a mode-locked fiber laser;

a first pulse stretcher configured for stretching said laser pulses to produce one or more stretched laser pulses;

a fiber amplifier coupled between said laser pulse source and said first pulse stretcher;

an amplifier configured to receive each of said stretched pulses to produce amplified stretched pulses, wherein said amplifier comprises at least a regenerative amplifier; and

a pulse compressor configured for producing one or more compressed amplified laser pulses obtained from stretched amplified laser pulses;

wherein a frequency shift in said fiber amplifier is used to tune said laser pulse source wavelength to said regenerative amplifier wavelength.

2. The laser apparatus of claim 1, wherein said fiber amplifier uses at least anomalous dispersion or a chirped pulse input to spectrally narrow said laser pulses output from said laser pulse source.

3. The laser apparatus of claim 1, wherein said fiber amplifier is a multimode fiber amplifier.

4. The laser apparatus according to 3, wherein the area of said multi-mode fiber amplifier is large enough to avoid spectral broadening.

5. The laser apparatus of claim 3, wherein said multimode fiber is a multimode photonic crystal fiber amplifier.

6. The laser apparatus of claim 1, wherein said fiber amplifier is pumped by a co-propagating pump laser and a counter-propagating pump laser to tune said laser pulse source wavelength to said regenerative amplifier wavelength.

7. The laser apparatus of claim 1, wherein said fiber amplifier comprises a Yb:

or Nd;

fiber amplifier that spectrally broadens said laser pulses output from said laser pulse source.

9. A laser apparatus, as claimed in claim 1, further including

a second pulse stretcher coupled to said laser pulse source;

and

said fiber amplifier being coupled to said second pulse stretcher and said first pulse stretcher.

8. A laser apparatus, comprising:

a laser pulse source comprising a mode-locked fiber laser;

a first pulse stretcher configured for stretching said laser pulses to produce one or more stretched laser pulses;

a fiber amplifier coupled between said laser pulse source and said first pulse stretcher;

an amplifier configured to receive each of said stretched pulses to produce amplified stretched pulses, wherein said amplifier comprises at least a regenerative amplifier; and

a pulse compressor configured for producing one or more compressed amplified laser pulses obtained from stretched amplified laser pulses;

wherein a frequency shift in said fiber amplifier is used to spectrally narrow said laser pulses output from said laser pulse source.

10. A mode locked laser system for seeding a regenerative amplifier, comprising:

a source of laser pulses;

a Yb;

fiber amplifier for amplifying said pulses;

and a regenerative amplifier based on Nd;

or Yb;

or Ti;

Al₂O₃ materials for receiving said amplified pulses as seed pulses,

wherein at least one of said pulse source or said Yb;

fiber amplifier includes means for controlling a bandwidth and a spectral center of its output for spectral matching to said regenerative amplifier.