1.6 W high wall plug efficiency, continuous-wave room temperature quantum cascade laser emitting at 4.6μm

A strain-balanced, InP-based quantum cascade laser structure designed for light emission at $4.6\mu \mathrm{m}$ was grown by metal-organic chemical vapor deposition. A maximum total optical power of $1.6\mathrm{W}$ was obtained in continuous-wave mode at $300\mathrm{K}$ for uncoated devices processed in buried heterostructure geometry with stripe dimensions of $5\mathrm{mm}$ by $9.5\mu \mathrm{m}$ . Corresponding maximum wall plug efficiency and threshold current density were measured to be 8.8% and $1.05\mathrm{kA}∕{\mathrm{cm}}^2$ , respectively. Fully hermetically packaged laser of identical dimensions produced in excess of $1.5\mathrm{W}$ under the same conditions.