Fig. 1. Schematic diagram of narrow-linewidth semiconductor laser based on external cavity feedback of micro-ring resonator

Fig. 2. Diagram of measurement device

Fig. 3. Change curves between the drive current, output power and TEC set temperature of the laser. (a) Output power of laser with different driving current varies with TEC set temperature; (b) output power of the laser varies with driving current

Fig. 4. Output power of the laser varies with the voltage of the phase heater

Fig. 5. Wavelength tuning range, spectral diagram and wavelength change curves with set temperature of gain chip TEC. (a) Laser wavelength tuning range; (b) optical spectra of the laser; (c) variation curves of laser wavelength with TEC set temperature

Fig. 6. Low frequency noise spectra and high frequency white noise spectra of laser. (a) Low frequency noise spectra; (b) high frequency white noise spectra

Fig. 7. Spectra of relative intensity noise

Fig. 8. Output optical power stability of ECL