Distributed-feedback Ga In As ∕ Al As Sb quantum-cascade lasersoperating at 300 K

Short-wavelength ( λ ∼ 4 μ m ) single-mode distributed-feedback Ga In As ∕ Al As Sb quantum-cascade lasers operating in pulsed mode up to room temperature ( 300 K ) have been demonstrated by etching an index-coupled first-order distributed-feedback grating into the upper GaInAs separate confinement layer. The temperature-dependent wavelength shift of the distributed-feedback lasers is − 0.14 cm − 1 ∕ K ( 0.238 nm ∕ K ) . For devices with a size of 18 μ m × 2.9 mm mounted epilayer-up with as-cleaved facets, a maximum peak power per facet of 840 mW has been achieved at 77 K and 4 mW at 300 K . The characteristic temperature T 0 of the threshold current density is 105 K .