High-Power Single-Longitudinal-Mode DFB Semiconductor Laser Based on Sampled Moiré Grating

In this mymargin letter, we experimentally demonstrated a 1550-nm high-power single-longitudinal-mode (SLM) distributed feedback (DFB) semiconductor laser based on sampled moiré grating (SMG). By designing the sampling structure with micrometer scale, moiré grating (MG) can be equivalently realized along the laser cavity. Then, we can reduce the coupling coefficient near laser facet so as to increase the output power. The cavity length and ridge width of the fabricated laser are 1.0 mm and
$3.0~\mu \text{m}$
, respectively. The measured threshold current and the slope efficiency are 30.0 mA and 0.36 mW/mA at the heat-sink temperature of 25 °C, respectively. When the injection current is 800.0 mA, the maximum output power is about 183.0 mW. The saturation power is significantly improved compared with conventional DFB laser with uniform sampled grating (USG), which was fabricated on the same wafer. In addition, a four-channel DFB laser array based on SMG was also fabricated on the same wafer, showing good wavelength uniformity.