Fig. 1. The reported 2-μm all-fiber nonlinear pulse compressors. (a) Pulse compression ratio versus pulse repetition rate. Label: the reported values of the pulse compression ratio. (b) Pulse duration versus pulse repetition rate. Label: the output average power. HNLF, highly nonlinear fiber; NDF, normal dispersion fiber; MFD, mode-field diameter; pulse compression ratio, the ratio between the driving laser pulse and the compressed laser pulse.

Fig. 2. Schematic diagram of the NDF-based all-fiber nonlinear pulse compressor. λ/2, half-wave plate; PMF, polarization maintaining fiber; NDF, normal dispersion fiber; SMF, single-mode fiber.

Fig. 3. (a) The laser spectrum of the ultrafast driving laser pulse versus average power. (b) The full width at half maximum (FWHM) of the laser spectrum and pulse duration versus average power. Inset: the autocorrelation trace of the driving laser pulse at the maximum average power of 2.14 W.

Fig. 4. (a) The output power of the all-fiber nonlinear pulse compressor versus the driving laser power. Inset: the power stability at the maximum output power measured within 1 hour. (b) The measured spectrum output from the all-fiber nonlinear pulse compressor versus the driving laser power. (c) The output spectrum from the all-fiber nonlinear pulse compressor at the maximum output power of 1.28 W (red line), the output spectrum behind NDF1 (blue dashed line) and the input driving laser spectrum at the maximum power of 2.14 W (black line). (d) The radio frequency spectrum of the compressed laser pulse within the scanning range of 1 MHz with a resolution bandwidth (RBW) of 300 Hz.

Fig. 5. (a) The pulse duration of the compressed pulse versus input driving laser power. (b) The measured autocorrelation trace of the compressed laser pulse at the maximum input driving laser power of 2.14 W.

Fig. 6. The simulated pulse (a)–(f) and spectrum (g)–(l) at the output port of each piece of fiber along the all-fiber nonlinear pulse compressor.

Fig. 7. (a) The simulated (red line) and measured (black line) spectra of the ultrafast driving laser pulse. (b) The simulated (red line) and measured (black line) spectra at the output port of NDF1. (c) The simulated (red line) and measured (black line) spectra at the output port of SMF2. (d) The simulated and FTL pulses at the highest output power.

Table 1. The parameters of the employed fibers in the 2-μm all-fiber nonlinear pulse compressor.