HYBRID FIBER-MOPA

• US 20110310468A1
• Filed: 06/22/2010
• Published: 12/22/2011
• Est. Priority Date: 06/22/2010
• Status: Active Grant

• Current Assignee: Coherent Inc (Coherent Corp.)
• Original Assignee: Coherent Inc (Coherent Corp.)
• Inventors: Hodgson, Norman, Spinelli, Luis A., Hertwig, Michael
• Granted Patent: US 8,508,844 B2
• Time in Patent Office: Days
• US Class Current: 359/341.3
• 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 3/0064 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 3/0405 Conductive cooling, e.g. by heat sinks or thermo-electric elements
• CPC Class Codes: H01S 3/0604 in the form of a plate or disc
• CPC Class Codes: H01S 3/0621 Coatings on the end-faces, e.g. input/output surfaces of the laser light
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• CPC Class Codes: H01S 3/094053 Fibre coupled pump, e.g. delivering pump light using a fibre or a fibre bundle
• CPC Class Codes: H01S 3/094084 with pump light recycling, i.e. with reinjection of the unused pump light, e.g. by reflectors or circulators
• 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 3/1611 neodymium
• CPC Class Codes: H01S 3/1673 YVO4 [YVO]
• CPC Class Codes: H01S 3/2316 Cascaded amplifiers
• CPC Class Codes: H01S 3/2325 Multi-pass amplifiers, e.g. regenerative amplifiers
• CPC Class Codes: H01S 3/2341 Four pass amplifiers

Abstract

A master oscillator power-amplifier stages includes multiple stages of fiber-amplification with a final power amplifier stage in the form of a multi-pass amplifier. With a thin-disk gain medium in one example the thin-disk amplifier includes a common optical arrangement for providing multiple incidences of radiation to be amplified and multiple incidences of a pump-radiation beam on the thin-disk gain medium.

Claims

1. Optical apparatus, comprising:

a master oscillator providing laser-radiation pulses;

a plurality of fiber-amplifier stages arranged sequentially for pre-amplifying the laser-radiation pulses; and

a multi-pass thin-disk amplifier including arranged for power amplifying the pre-amplified laser-radiation pulses from the fiber-amplifier stages, the thin-disk amplifier including a thin-disk gain-medium, and a source of optical pump radiation for energizing the thin-disk gain-medium.

2. The apparatus of claim 1, wherein the master oscillator is one of a mode-locked fiber laser, a directly modulated diode-laser or an externally modulated CW laser.

3. The apparatus of claim 1, wherein the pulses provided by the master oscillator have a duration between about 1 picosecond and about 100 nanoseconds.

4. The apparatus of claim 1, wherein the master oscillator provides the pulses of laser radiation at a pulse repetition frequency between about 10 kHz and 400 MHz.

5. The apparatus of claim 1, wherein the thin-disk amplifier includes a first optical arrangement for causing multiple incidences of the radiation pulses to be amplified on the thin-disk gain-medium, and a separate second optical arrangement for causing multiple incidences of the optical pump radiation on the thin-disk gain-medium.

6. The apparatus of claim 1, wherein the thin-disk amplifier includes an optical arrangement for causing multiple incidences of the radiation pulses to be amplified on the thin-disk gain-medium, and multiple incidences of the optical pump radiation on the thin-disk gain-medium.

7. The apparatus of claim 6, wherein the radiation pulses and the optical pump radiation propagate on the same path in the optical arrangement.

8. The apparatus of claim 1, wherein the pre-amplified laser pulses are un-polarized.

9. The apparatus of claim 1, wherein the pre-amplified laser pulses are plane-polarized.

10. The apparatus of claim 9, wherein the thin-disk laser amplifier is a polarization-maintaining amplifier.

11. Optical apparatus, comprising:

a master oscillator providing laser-radiation pulses;

a plurality of fiber-amplifier stages arranged sequentially for pre-amplifying the laser-radiation pulses; and

a multi-pass thin-disk amplifier including arranged for power amplifying the pre-amplified laser-radiation pulses from the fiber-amplifier stages, the thin-disk amplifier including a thin-disk gain-medium, a source of optical pump radiation for energizing the thin-disk gain-medium, and an optical arrangement for causing multiple incidences of the radiation pulses to be amplified on the thin-disk gain-medium, and multiple incidences of the optical pump radiation on the thin-disk gain-medium.

12. The apparatus of claim 11, wherein the radiation pulses and the optical pump radiation propagate on the same path in the optical arrangement.

13. The apparatus of claim 11, wherein the pre-amplified laser radiation pulses are plane polarized and the multi-pass thin-disk amplifier is a polarization-maintaining amplifier.

14. Apparatus for amplifying laser radiation, comprising:

a thin-disk gain medium;

a source of optical pump radiation for energizing the thin-disk gain-medium; and

an optical arrangement for causing both multiple incidences of the laser to be amplified on the thin-disk gain-medium, and multiple incidences of the optical pump radiation on the thin-disk gain-medium.

15. The apparatus of claim 14, wherein the laser radiation is plane-polarized in a predetermined polarization orientation and wherein the optical arrangement is configured such that the polarization-orientation of the laser radiation is about the same on each incidence of the laser radiation on the thin-disk gain-medium.

16. The apparatus of claim 14, wherein the laser radiation and the optical pump radiation co-propagate in the optical arrangement on a common path.