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HL: Fachverband Halbleiterphysik
HL 36: Focussed Session: Frontiers in Laser Diode Physics I
HL 36.2: Hauptvortrag
Donnerstag, 15. März 2018, 10:00–10:30, EW 202
Recent progress on VCSELs for the near- to mid-infrared spectral region — •Markus Amann — Walter Schottky Institut, TU München, 85748 Garching, Am Coulombwall 4
Previously, near-infrared Vertical-Cavity Surface-Emitting Lasers (VCSELs) have emerged as versatile single-mode, wavelength-tunable and high-speed laser diodes for numerous applications in communications and sensing. This is because of their intrinsic advantages against edge-emitting lasers such as sub-milliamp threshold currents, high slope efficiencies, low beam divergence and corresponding simple fiber-coupling. Extending the lasing regime further into the mid-infrared, however, is challenged by strong increase (∝λ2) of free-carrier absorption, enhanced Auger recombination, and low thermal conductivity of the underlying quaternary and quinternary alloys.
Recently, the operation wavelengths of VCSELs were significantly increased further into the near- and even mid-infrared by the introduction of the Buried-Tunnel-Junction (BTJ) technology and the application of new materials and quantum well designs. We present InP-based BTJ-VCSELs that operate at wavelengths up to 2.6µm by using type-II heterostructure active regions. With active regions based on the AlGaInAsSb material system, optimized type-I and type-II heterostructures yield emission wavelengths in the entire 3-4µm wavelength range. All devices operate in continuous-wave at room temperature, show an excellent single-mode emission with SMSR of 30dB and a continuous electro-thermal wavelength tunability up to about 20nm.