High-power, rare-earth-doped crystal amplifier based on ultra-low-quantum-defect pumping scheme Utilizing single or low-mode fiber lasers

Patent metadata

Field	Value
Publication number	US-11316319-B2
Application number	US-201716465021-A
Country	US
Kind code	B2
Filing date	Dec 1, 2017
Priority date	Dec 1, 2016
Publication date	Apr 26, 2022
Grant date	Apr 26, 2022

Abstract

A high average and peak power single transverse mode laser system is operative to output ultrashort single mode (SM) pulses in femtosecond-, picosecond- or nanosecond-pulse duration range at a kW to MW peak power level. The disclosed system deploys master oscillator power amplifier configuration (MOPA) including a SM fiber seed, outputting a pulsed signal beam at or near 1030 nm wavelength, and a Yb crystal booster. The booster is end-pumped by a pump beam output from a SM or low-mode CW fiber laser at a pump wavelength in a 1000-1020 nm wavelength range so that the signal and pump wavelengths are selected to have an ultra-low-quantum defect of less than 3%.

First claim

The invention claimed is:

1. A high power single mode (SM) laser system comprising:
a master oscillator power amplifier (MOPA) configuration including:
a single mode (SM) seed outputting pulsed signal beam at or around a 1030 nm wavelength λs,
a booster including an ytterbium (Yb) doped crystal or Yb crystal ceramic receiving the pulsed signal beam;

a singlemode (SM) or low-mode (LM), continuous-wave (CW) fiber laser outputting a high brightness pump beam at a wavelength λp in a 1000 1020 nm wavelength range to end-pump the booster, wherein the pulsed signal and pump beams propagate substantially coaxially or collinearly overlapping one another in a range between 80 and 100% so as so as to provide an ultra-low quantum defect; and
first and second wavelength discriminators flanking the booster, wherein the first and second wavelength discriminators each being a dichroic mirror or volume Bragg grating (VBG).

2. The high power SM laser system of claim 1 , wherein the ultra-low quantum defect is less than 3%.

3. The high power SM laser system of claim 1 or 2 , wherein the booster includes an Yb:YAG crystal, and the Yb crystal ceramic is Yb 2 O 3 ceramic, the booster being shaped as a plate or rod.

4. The high power SM laser system of claim 1 or 2 , wherein the wavelength λp of the high brightness pump beam varies in a 1006-1010 nm wavelength range, the ultra-low quantum effects being between 2 and 2.5%.

5. The high power SM laser system of claim 1 , wherein the SM or LM CW fiber laser is operative to output the pump beam of up to a few kWs.

6. The high power SM laser system of claim 1 , wherein the SM seed is configured as one or more laser diodes or a SM fiber laser operative to output a train of ultrashort signal light pulses in a fs-, ps- or ns- pulse duration range.

7. The high power SM laser system of claim 1 , wherein the signal beam at an output of the booster characterized by:
an average pulse power which varies from several hundred watts to kWs, and
an energy per pulse in several hundred micrjoules to several milljoules range.

8. The high power SM laser system of claim 1 , wherein the SM seed includes a mode-locked fiber laser.

9. The high power SM laser system of claim 1 , wherein the SM seed operates in a pure pulsed mode or burst mode.

10. The high power SM laser system of claim 1 , wherein the CW high brightness fiber laser outputs the pump beam such that the pump beam is coupled into one of opposite ends of the booster or both ends.

11. A booster comprising:
an ytterbium (Yb) bulk amplifier receiving a SM signal beam at or around a 1030 nm wavelength; and
a single or low-mode, continuous-wave (CW) fiber laser outputting high brightness pump beam coupled into one of opposite or both facets of the Yb bulk amplifier at a wavelength λp in a 1000-1020 nm wavelength range, wherein the SM signal and pump beams propagate overlapping one another at more than 80% so as to provide an ultra-low quantum defect of less than 3%; and further comprising at least one pre-amplifying stage.

12. The booster of claim 11 , wherein the Yb bulk amplifier is configured to be a slab or rod, the ultra-low quantum defect being between 2 and 2.5%.

13. The booster of claim 11 , wherein the Yb bulk amplifier includes a Yb:YAG or Yb 2 O 3 ceramic.

Assignees

• Ipg Photonics Corp

Inventors

• Dergachev Alex
• Samartsev Igor
• Gapontsev Valentin

Classifications

• H01S3/094042

  of a fibre laser · CPC title

• H01S3/08045

  Single-mode emission · CPC title

• H01S3/0602

  Crystal lasers or glass lasers (H01S3/063 takes precedence) · CPC title

• H01S3/1618 Primary

  ytterbium · CPC title

• H01S3/1685

  Ceramics · CPC title