High-Power Laterally Coupled Distributed Feedback Lasers With Metal Gratings Around $2~\mu$ m

We report on the fabrication of high-power type-I laterally coupled distributed feedback lasers with metal gratings emitting around 2 μm. The second-order Cr-Bragg gratings were patterned alongside the ridge waveguide by lift-off. Single-mode continuous-wave operation with side mode suppression ratio as high as 40 dB is achieved. For lasers with cavity length of 800 μm, the maximum output power is exceeding 28 mW per facet at room temperature without facet coating. The optoelectronic conversion efficiency is as high as 6.3% with a high slope efficiency of 0.1 W/A. The lasers show a narrow line width of 20 MHz with a good beam quality, and the characteristic temperature T
₀
is as high as 130 K.