Fig. 1. Working schematics of echelle grating. (a) Angle distribution; (b) off-axis angle γ

Fig. 2. Light path of cross dispersion based on diffraction grating and echelle grating

Fig. 3. Tunable fiber laser system based on echelle grating. (a) Structural diagram; (b) bulk optics light path

Fig. 4. Hologram uploaded onto DMD

Fig. 5. Typical signal of laser output

Fig. 6. 3 dB width of signal versus modulation pixel number on DMD in closed and open loops

Fig. 7. Wavelength tuning output signal from tunable fiber laser. (a) Coarse tuning; (b) fine tuning

Fig. 8. Wavelength and power stabilities of fiber laser