Single-Mode Quantum Cascade Laser Array Emitting From a Single Facet

We present an array of single-mode quantum cascade lasers operating in the range 8-9.5 μm. The resonator features a pair of distributed Bragg reflectors for the mode selection, together with a second-order extraction grating. The radiation of these substrate emitting devices was combined in a single collector ridge. A proof of principle featured seven laser devices with a coverage of 170 cm
^-1
. The functionality of our approach is corroborated with a set of polarization and near-field measurements confirming the collection of multiple frequencies in a unique ridge.