Microchip-Yb fiber hybrid optical amplifier for micro-machining and marking

• US 20060171018A1
• Filed: 03/10/2006
• Published: 08/03/2006
• Est. Priority Date: 03/21/1997
• Status: Active Grant

• Current Assignee: IMRA America Incorporated (Aisin Corp.)
• Original Assignee: IMRA America Incorporated (Aisin Corp.)
• Inventors: Galvanauskas, Almantas, Harter, Donald J., Raksi, Ferenc, Fermann, Martin E.
• Granted Patent: US 7,656,578 B2
• Time in Patent Office: Days
• US Class Current: 359/333
• 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 3/0604 in the form of a plate or disc
• CPC Class Codes: H01S 3/0606 with polygonal cross-section, e.g. slab, prism H01S3/0604 takes precedence
• CPC Class Codes: H01S 3/06754 Fibre amplifiers H01S3/06708 takes precedence
• CPC Class Codes: H01S 3/08031 Single-mode emission
• CPC Class Codes: H01S 3/094007 Cladding pumping, i.e. pump light propagating in a clad surrounding the active core
• CPC Class Codes: H01S 3/09415 the pumping beam being parallel to the lasing mode of the pumped medium, e.g. end-pumping
• CPC Class Codes: H01S 3/115 using intracavity electro-optic devices
• CPC Class Codes: H01S 3/1611 neodymium
• CPC Class Codes: H01S 3/1618 ytterbium
• CPC Class Codes: H01S 3/1673 YVO4 [YVO]

Abstract

The invention describes techniques for the control of the spatial as well as spectral beam quality of multi-mode fiber amplification of high peak power pulses as well as using such a configuration to replace the present diode-pumped, Neodynium based sources. Perfect spatial beam-quality can be ensured by exciting the fundamental mode in the multi-mode fibers with appropriate mode-matching optics and techniques. The loss of spatial beam-quality in the multi-mode fibers along the fiber length can be minimized by using multi-mode fibers with large cladding diameters. Near diffraction-limited coherent multi-mode amplifiers can be conveniently cladding pumped, allowing for the generation of high average power. Moreover, the polarization state in the multi-mode fiber amplifiers can be preserved by implementing multi-mode fibers with stress producing regions or elliptical fiber cores These lasers find application as a general replacement of Nd: based lasers, especially Nd:YAG lasers. Particularly utility is disclosed for applications in the marking, micro-machining and drilling areas.

Claims

1-10. -10. (canceled)

11. An apparatus for generating a pulsed laser output with a pulse width in the picosecond—

low nanosecond regime and a pulse energy sufficient for micromachining or surgical applications, comprising;

a seed source producing seed pulses;

a fiber amplifier unit receiving said seed pulses and producing pulses with a pulse energy in a predetermined range;

said fiber amplifier unit including at least one multi-mode fiber amplifier adapted to propagate single-mode light;

at least one bulk optical element receiving at least the output of said multimode amplifier; and

a delivery system for said laser output.

12. An apparatus for generating a pulsed laser output with a pulse width in the picosecond—

low nanosecond regime and a pulse energy sufficient for micromachining or surgical applications, comprising;

a seed source producing seed pulses;

a fiber amplifier unit receiving said seed pulses and producing pulses with a predetermined pulse energy;

said fiber amplifier unit including at least one multi-mode fiber amplifier adapted to propagate single-mode light; and

at least one bulk optical element which frequency converts the pulses produced by said fiber amplifier unit, and

a delivery system for said laser output.

13. An apparatus for generating a pulsed laser output with a pulse width in the picosecond—

low nanosecond regime and a pulse energy sufficient for micromachining or surgical applications, comprising;

a seed source producing seed pulses;

a fiber amplifier unit receiving said seed pulses and producing pulses with a predetermined pulse energy;

said fiber amplifier unit including at least one multi-mode fiber amplifier adapted to propagate single-mode light; and

at least one bulk optical element which amplifies the pulses produced by said fiber amplifier unit; and

a delivery system for the laser output.

14. An apparatus for generating a pulsed laser output with a pulse width in the picosecond—

low nanosecond regime and a pulse energy sufficient for micromachining or surgical applications, comprising;

a seed source producing seed pulses;

a fiber amplifier unit receiving said seed pulses and producing pulses with a predetermined pulse energy;

said fiber amplifier unit including at least one multi-mode fiber amplifier adapted to propagate single-mode light; and

a compressor unit for compressing said pulses prior to output; and

a delivery system for said laser output.

15. An optical apparatus for generating pulses with a pulse width in the picosecond—

low nanosecond regime, comprising;

a seed source producing seed pulses;

a fiber amplifier unit receiving said seed pulses and producing an amplified output;

said fiber amplifier unit including at least one multi-mode fiber amplifier adapted to propagate single-mode light; and

at least one bulk optical element receiving at least the output of said multimode amplifier.

16. An optical apparatus for generating pulses with a pulse width in the picosecond—

low nanosecond regime, comprising;

a seed source producing seed pulses;

a fiber amplifier unit receiving said seed pulses and producing an amplified output;

said fiber amplifier unit including at least one multi-mode fiber amplifier adapted to propagate single-mode light; and

at least one bulk optical element which frequency converts the pulses produced by said fiber amplifier unit.

17. An optical apparatus for generating pulses with a pulse width in the picosecond—

low nanosecond regime, comprising;

a seed source producing seed pulses;

a fiber amplifier unit receiving said seed pulses and producing an amplified output;

said fiber amplifier unit including at least one multi-mode fiber amplifier adapted to propagate single-mode light; and

at least one bulk optical element which amplifies the pulses produced by said fiber amplifier unit.

18. An optical apparatus for generating pulses with a pulse width in the picosecond—

low nanosecond regime;

a seed source producing seed pulses;

a fiber amplifier unit receiving said seed pulses and producing amplified pulses;

said fiber amplifier unit including at least one multi-mode fiber amplifier adapted to propagate single-mode light; and

a compressor unit for compressing said pulses prior to output.