Continuous-wave operation of GaInAsSb-GaSb type-II quantum-well ridge-lasers

High efficiency GaInSbAs/GaSb type-II quantum well continuous wave lasers

“…The internal quantum efficiency determined from these data is as high as 89%. The internal losses were reduced to 7.8 cm −1 comparing with our previous works [7,8] owing to the smaller penetration of the light wave into heavily doped cladding layers because of the increased thickness of the waveguide.…”

“…The tendency to single longitudinal mode operation of GaSb-based Fabry-Pérot ridge lasers was noted earlier [8] but no explanation of its origin was given.…”

“…Before the first cladding layer and after the second one 100 nm thick graded GaAlSbAs layers were grown to reduce the series resistance of the structure. Compared to the previously reported structure [8] the total thickness of the active zone was increased up to 0.8 µm in order to reduce optical losses according to the conception of a broadened waveguide [11].…”

“…10 µm wide shallow mesa ridge lasers were fabricated from the grown wafer using the process described in [8]. Cleaved Fabry-Pérot (250-1000) µm long devices with uncoated facets were soldered p-side down onto copper heat sinks with a tin-lead alloy.…”

“…Besides, with a proper design of the type-II active zone non-radiative Auger processes can be significantly suppressed, which is very important for mid-infrared diode lasers [5]. Low threshold type-II GaInSbAs/GaSb QW lasers emitting between 2 and 2.65 µm at RT have been reported [6][7][8]. The threshold current density of these lasers is comparable with that of the type-I structures but their internal quantum efficiency did not exceed 47% and the cw optical power of only 2 mW has been achieved at RT.…”