Room temperature operated diffraction limited λ ≈3 μm diode lasers with 37 mW of continuous-wave output power

Single spatial mode GaSb-based type-I quantum well diode lasers operating near 3 μm at room temperature were designed and fabricated by chlorine-free dry etching technique. The etching profile was optimised to minimise the optical loss. The 5.5 μm-wide ridge lasers demonstrated the same slope efficiency as that of 100 μm-wide multimode devices and generated 37 mW of continuous-wave output power at 17°C.