Fig. 1. Absorption lines of H2O, HCl, CH4, and NO as a function of wavelength, in the spectral range from 1.6 to 1.9 μm. Data are taken from the HITRAN database.

Fig. 2. (a) Schematic of two-section DBR laser structure. Inset, SEM image of butt-jointed interface between active region and passive waveguide; (b) PL spectra of the active region material and the passive region material. Bragg wavelength before tuning is also marked with a blue dot.

Fig. 3. Optical output power characteristics versus gain current at various temperatures. Bragg section current is 0 mA. Inset, threshold current dependence on the temperature.

Fig. 4. Output power and emitting wavelength as a function of gain current.

Fig. 5. Lasing spectrum as a function of temperature with fixed gain current of 80 mA.

Fig. 6. Tuning range obtained by only changing IDBR at 25 °C. Igain is fixed to 80 mA. Maximum tuning range of 10 nm is obtained.

Fig. 7. Overlapped spectra of different wavelength when changing the current of the Bragg section only.