Fig. 1. Overview of the compressed pulse energy versus the corresponding pulse duration of the EDFOs and EDFAs. Environmentally stable laser configurations are marked as solid patterns, and non-PM laser configurations are marked as hollow patterns.

Fig. 2. (a) Laser system setup. LD-1, LD-2, and LD-3, single-mode fiber coupled laser diode with a maximum output power of 400 mW at 976 nm; ESF, Er-doped single-mode fiber with negative GVD; CIR, circulator; WDM-1, WDM-2, WDM-3, and WDM-4, wavelength division multiplexer; OC-1 and OC-2, fiber couplers with 30:70 and 10:90 splitting ratio, respectively; F-ISO, fiber-coupled isolator; F-PBS, fiber-coupled polarization beam splitter; EDF, Er-doped single-mode fiber with positive GVD; FRM-1 and FRM-2, Faraday rotation mirror; COL-1, input collimator; COL-2, output collimator; HWP, half-wave plate; ISO, isolator; PBS, polarization beam splitter cube; LD-4, laser diode with 9 W output power; EYDCF, 12/130 Er–Yb codoped double-clad fiber with numerical aperture of 0.2 for the fiber core and 0.46 for the cladding. (b) Optical alignment of the ×64 divider, with the inline YVO4-based stages as well as the PBS-based stages. N in 2N represents the stage order. The red dash line OA, red dot line h, and θ represent the crystal optical axis, horizontal line, and angle between them, respectively.

Fig. 3. (a) Spectral curve and (b) AC trace of the seed pulse at 10 MHz repetition rate. Pulse durations (red square curve) and combining efficiencies (blue square curve) as functions of the pumping power of the (c) pre-amplifier and (d) main amplifier, respectively.

Fig. 4. (a) Spectral and (b) temporal characters of the amplified pulse with 64 replicas. (c) Spectral and (d) temporal characters of the frequency-doubled pulse.