Fig. 1. Schematic of mode-locked Yb-fiber laser and the details of spatial optical path. PZT, piezoelectric ceramic transducer; PBS, polarization beam splitter; SESAM, semiconductor saturable absorption mirror; PM-CFBG, polarization-maintained chirped fiber Bragg grating; PM SMF, polarization-maintained single mode fiber; WDM, wavelength division multiplexer

Fig. 2. Dechirped pulse duration and Gaussian fitting R-square of output spectra when the NCD is changed from −4.42×10⁻² ps² to 1.70×10⁻³ ps². (a) Output spectrum when NCD is −4.42×10⁻² ps², FWHM=5.4 nm; (b) Output spectrum when NCD is −2.10×10⁻² ps², FWHM=7.4 nm; (c) Output spectrum when NCD is −6.50×10⁻³ ps², FWHM=5.4 nm; (d) Dechirped pulse duration and Adj. R-square versus net cavity dispersion

Fig. 3. The output spectra and SSE values under different NCD when tuning the optical delay line. Each graph consists of 6 spectra with different repetition rate. The NCD of each graph is (a) 0 ps², (b) −1.13×10⁻² ps², (c) −2.26×10⁻² ps², (d) −3.39×10⁻² ps², (e) −4.52×10⁻² ps², (f) −5.65×10⁻² ps², respectively

Fig. 4. (a) 3-D model of the compact mechanical structure, the overall dimension is 320 mm×220 mm×65 mm. (b) Appearance of the compact laser. (c) Schematic of the repetition rate locking system

Fig. 5. (a) Autocorrelation trace of the output of the compact system @36 mW pump power. (b) Output spectrum of the compact system @36 mW pump. (c) Radiofrequency spectrum of the compact system with resolution bandwidth of 30 Hz

Fig. 6. (a) Repetition rate of the fundamental harmonic of the output signal under free-running state. (b) Allan deviation of the repetition rate under free-running state. (c) Repetition rate of the fundamental harmonic of the output signal with feedback loop activated. (d) Allan deviation of the repetition rate with feedback loop activated