Fig. 1. The schematic diagram of the Kumgang laser system.

Fig. 2. The MOPA beam combination laser with the amplitude combining method using PBSs: EM1–EM6, energy meters.

Fig. 3. MOPA beam combination laser with the amplitude combining method using a VBG.

Fig. 4. Types of SBS-PCM: (a) conventional SBS-PCM and (b) self-phase-locking SBS-PCM with PZT.

Fig. 5. Experimental setup of the self-phase-locked SBS-PCM: BS, beam splitter; W1 and W2, wedges; CM1 and CM2, concave mirrors.

Fig. 6. Experimental result of the self-phase-locked SBS-PCM. (a) A mosaic intensity pattern. It is generated by lining up one line of the intensity profile pattern recorded at each CCD image. (b) The measured relative phase. The standard deviation of the measured phase fluctuation is .

Fig. 7. Experimental setup of beam combination using an SBS-PCM and a feedback loop: M, mirror; W, wedged window; CM, concave mirror.

Fig. 8. Experimental result of beam combination using an SBS-PCM and a feedback loop: (a) without operating the feedback loop and (b) with operation of the feedback loop.

Fig. 9. Experimental setup of the four-beam combination using an SBS-PCM with the amplitude dividing method: , , , , , and , energy detectors; CM, concave mirror.

Fig. 10. Measured phase fluctuation of four-beam combination using an SBS-PCM with the amplitude dividing method.

Fig. 11. Experimental setup of the four-beam combination amplifier using an SBS-PCM with the wavefront dividing method: HWP1 and HWP2, half-wave plates; BS, beam splitter; P1–P3, Prisms; M1–M3, mirrors; AMP1–AMP4, amplifiers; C1–C4, concave mirrors; W, wedge.

Fig. 12. Measured phase fluctuation of the four-beam combination amplifier using an SBS-PCM with the wavefront dividing method.

Fig. 13. Schematic diagram of the front end: FC/APC, fiber connector/angled physical contact; WDM, wavelength division multiplexor; BPF, bandpass filter; FC, fiber collimator; HR1 and HR2; high-reflectivity mirrors; A1 and A2, apertures.

Fig. 14. Schematic diagram of the pre-amplifier: RL1–RL5, relay lens pairs; PR1 and PR2, polarization rotators; HR, high-reflectivity mirror.

Fig. 15. Schematic diagram of the main amplifier: RL1–RL20, relay lens pairs; CM1–CM4, concave mirrors.

Fig. 16. Schematic diagram of 2D laser processing using the Kumgang laser.

Fig. 17. Schematic diagram of the generation of a fs/ps laser using the Kumgang laser as a pump source: OPA1–OPA3, optical parametric amplifiers.