Fig. 1. Principle of CPA technology in optical fibers

Fig. 2. Schematic of a double-cladding fiber amplifier

Fig. 3. Structural diagram of gain photonic crystal fibers. (a) A double-cladding PCF; (b) a rod-type PCF

Fig. 4. CCC fibers. (a) Structural diagram of a CCC fiber; (b) cross-section of a CCC fiber; (c) structural diagram of a polygonal-CCC fiber with 8 side cores; (d) cross-section of a polygonal-CCC fiber with 8 side cores; (e) cross-section of a non-PM LCF; (f) cross-section of a PM LCF

Fig. 5. Cross-sections of fibers and mode field distribution. (a) Cross-section of a distributed mode filtering fiber; (b) cross-section of a large pitch fiber; (c) mode field distribution and corresponding overlap with doped area for mode field diameter of 26 μm; (d) mode field distribution and corresponding overlap with doped area for mode field diameter of 104 μm

Fig. 6. HOM fiber amplifier utilizing long period fiber gratings to convert the mode

Fig. 7. Structural diagrams of grating-pair strechers. (a) Martinez-type; (b) Offner-type

Fig. 8. Schematic of a single-prism pulse compressor

Fig. 9. Experimental setup of an FCPA system based on pre-compensation of third-order dispersion

Fig. 10. Pre-compensation of third-order dispersion. (a) SEM image of a negative third-order-dispersion fiber; (b) dispersion curves of a hybrid fiber stretcher; (c) dispersion curves of a normal fiber stretcher

Fig. 11. Principle of pulse stretching by a chirped fiber Bragg grating

Fig. 12. Structure and cross-section of an HC-PCF. (a) Structure of a prefabricated HC-PCF; (b) optical image of cross-section of an HC-PCF

Fig. 13. Experimental setup of a nonlinear amplification system with pre-chirp management

Fig. 14. Fiber self-similar amplifier. (a) Experimental setup; (b) interferometric AC trace (inset), PICASO-retrieved profile, and transform-limited pulse; (c) relative intensity noise (RIN) of the pulse amplifier with negative or positive chirp

Fig. 15. Filter consisting of multiple dielectric layers. (a) Structural diagram; (b) transmission characteristic

Fig. 16. High-power large-core double-cladding fiber amplifier and components. (a) Traditional spatial optical path; (b) all-fiber components; (c) schematic of an all-fiber femtosecond laser amplification system

Fig. 17. Schematic of coherent beam combining of ultrashort pulses

Fig. 18. Schematic of a fiber laser amplification system based on four-channel coherent beam combining

Fig. 19. Structural diagram of multi-core PCFs. (a) Seven-core PCF; (b) eighteen-core PCF

Fig. 20. Experimental setup of two-dimensional diffractive combination by utilizing two DOEs

Fig. 21. Principle of pulse dividing by optical splitters. (a) Birefringent crystals; (b) free-space delay lines

Fig. 22. Setup of divided-pulse amplification based on freespace delay lines

Fig. 23. Structural diagram of two-dimensional coherent combining based on actively controlled DPA combined with CBC

Fig. 24. Basic principle of a stack-and-dump enhancement cavity

Fig. 25. Schematic of an enhancement cavity

Fig. 26. Principle of a coherent pulse stacker in low-finesse GT cavity

Fig. 27. Coherent pulse stackers. (a) One-stage stacker with m cascaded GTI cavities; (b) two-stage stacker with m×m GTI cavities

Fig. 28. Development of high power ultrashort pulse fiber amplification systems

Fig. 29. Yb∶YAG SCFs. (a) Schematic of an Yb∶YAG SCF and a thin disk hybrid amplifier; (b) photos of thin-rod SCFs and thin-tapered-rod SCFs; (c) photo of a gain module