GaSb-based mid-infrared single lateral mode lasers fabricated by selective wet etching technique with an etch stop layer

We have demonstrated a wet etching technique for fabrication of narrow ridge lasers. Precise control over etching depth and ridge width was realized by introducing an etch stop layer into a laser structure and by using two etchants with different selectivity. The 6-μm-wide ridge laser emitting at 2 μm generated continuous-wave power of 70 mW at 20°C. Single lateral mode operation was observed up to 400 mA, corresponding to 8 × μth.