The antiguiding parameter in mid-infrared optically pumped semiconductor lasers

In this paper Hakki-Paoli method is used to measure the antiguiding parameter in three optically pumped mid-IR semiconductor lasers. Two of the lasers utilize W-quantum wells using 14 InAs/lnGaSb/lnAs wells imbedded in lattice-matched InGaAsSb layers. The thick quaternary layers act as a dilute waveguide as well as efficient absorbers of the pump radiation. The radiative transition is type-ll and occurs across the InAs to InGaSb interfaces. Wavelength tuning in this "broken-gap" band alignment is accomplished by increasing the width of the InAs electron wells which effectively lowers the energy of the trapped electronic state such that the emission moves to longer wavelengths. We compare the antiguiding parameter of two W-well lasers one with ~4 ML InAs the other with -5.5 ML of InAs operating at λ~3.5 μm and λ~4.5 μm, respectively. In addition, we compare the performance of the W-quantum well devices to a double heterostructure (DH) laser which contained a -1.5 μm InAsSb active region embedded in -2.5 μm thick AlAsSb clad regions. The emission of the DH was λ~3.8 μm. Laser devices were mounted epi-side down on a Cu heat sink and then placed in a LN2 cryostat which was cooled to 78K. The devices were pumped with the output of a λ = 1.85 μm laser diode array.