Fig. 1. Schematic of ECDL with the low loss Littman-Metcalf external-cavity configuration

Fig. 2. (a) Schematic diagram of semiconductor laser with external cavity feedback; (b) Equivalent resonator after introducing equivalent reflection coefficient

Fig. 3. Effect of first order diffraction efficiency of blazed gratings on the loss of external cavity semiconductor lasers

Fig. 4. Effect of the first order diffraction efficiency of a blazed grating on threshold current of an external cavity semiconductor laser

Fig. 5. Effect of the first order diffraction efficiency of a blazed grating on threshold current of an external cavity semiconductor laser

Fig. 6. Effects of the first order diffraction efficiency of the blazed grating on the output power of the external cavity semiconductor laser

Fig. 7. Effect of (a) the end-face reflectance of the semiconductor laser, (b) the length of internal cavity, (c) the length of external cavity, (d) the reflectance of M1, (e) the reflectance of M2 on the output linewidth of the low loss Littman-Metcalf external cavity semiconductor laser

Fig. 8. Effect of (a) the front-face reflectance of semiconductor laser, (b) the end-face reflectance of the semiconductor laser, (c) the length of external cavity, (d) the reflectance of M1, (e) the reflectance of M2 on the output power of the low-loss Littman-Metcalf external cavity semiconductor laser