Ultrawide dual contact strip fabricated quantum cascade lasers with reduced beam divergence angle.

Power scaling through the broadening of the laser core in Quantum Cascade Lasers can extract greater average power from devices at the cost of mode quality. To improve transverse mode quality for ultrawide (>100 µm) devices, a dual contact strip waveguide geometry is designed and demonstrated, utilizing a reduced top cladding thickness, and modifying the gold electrical epi-side contact to affect mode competition. A 200 µm wide Dual Contact Strip laser emitting at 4.