Mann, C.C.MannYang, QuankuiQuankuiYangFuchs, F.F.FuchsBronner, WolfgangWolfgangBronnerKiefer, R.R.KieferKöhler, KlausKlausKöhlerSchneider, H.H.SchneiderKormann, R.R.KormannFischer, H.H.FischerGensty, T.T.GenstyElsässer, W.W.Elsässer2022-03-092022-03-092003https://publica.fraunhofer.de/handle/publica/343237Quantum cascade lasers emitting at lambda about 5 µm based on different active region designs are investigated. Using lattice-matched GaInAs/ AlInAs on InP substrates the maximum peak optical power as well as the maximum pulsed-mode operating temperature is enhanced by incorporating AlAs blocking barriers together with strain-compensating InAs layers into the active regions. Further improvement is achieved by employing strain-compensated GaInAs/ AlInAs quantum wells for which maximum pulsed-mode operating temperatures in excess of 350 K are observed. High-reflectivity coated devices mounted substrate-side down show a maximum continuous-wave operating temperature of 194 K. Also the normalized relative intensity noise is investigated. Finally, a comparison trace-gas sensing experiment employing one of the present quantum cascade lasers and a lead-chalcogenide laser is presented. Detecting the P (25) absorption line of CO, higher stability is obtained using a quantum cascade laser.enquantum cascade laserQuantenkaskadenlasermid-infraredmittleres Infrarotcontinuous-wave operationDauerstrichbetriebtrace-gas sensingSpurengasanalyse621667conference paper