Fig. 1. 1.55-μm DFB laser. (a) Epitaxial structure of material; (b) scanning electron microscope (SEM) of grating cross section; (c) microscope graph of laser array

Fig. 2. Simulated and tested results. (a) κ versus InP thickness between grating and SCH; (b) reciprocal of differential quantum efficiency ηd versus cavity length

Fig. 3. P-I-V curves of 1-mm coated DFB laser array under CW operation at 22 ℃. (a) P-I curves of 5 channels (wavelengths) of DFB laser array; (b) P-I-V curves of channel 1

Fig. 4. Spectra of 1-mm coated DFB laser array under CW operation at 22 ℃. (a) Spectra of DFB laser array with bias current of 300 mA; (b) spectra of channel 1 of DFB laser at different currents

Fig. 5. Typical small signal responses under different bias currents at 22 ℃

Fig. 6. Typical optical linewidth of single DFB laser

Fig. 7. Typical RIN curves of DFB laser (22 ℃,450 mA)