Interband cascade laser progress - art. no. 69090X

Recent advances in the development of mid-IR antimonide type-II "W" interband cascade lasers have led to a considerably improved high-temperature operation of the devices. We report an experimental investigation of four interband cascade lasers with wavelengths spanning the mid-infrared spectral range, i.e., 2.9-5.2 mu m near room temperature in pulsed mode. One broad-area device had a pulsed threshold current density of only 3.8 A/cm(2) at 78 K (lambda = 3.6 mu m) and 590 A/cm(2) at 300 K (X = 4.1 mu m). The room-temperature threshold for the shortest-wavelength device (lambda = 2.6-2.9 mu m) was even lower, 450 A/cm(2). A cavity-length study of the lasers emitting at 3.6-4.1 mu m yielded an internal loss varying from 7.8 cm(-1) at 78 K to 24 cm-1 at 300 K, accompanied by a decrease of the internal efficiency from 77% to 45%. Preliminary cw testing led to a narrow-ridge device from one of the wafers with emission at lambda = 4.1 mu m operating to 288 K, a new record for interband devices in this wavelength range.