Characterization of GaSb based VCSE and MQW lasers for 2.3 µm sensing application

The MQW GaInAsSb/AlGaAsSb lasers are monomodal throughout almost the whole temperature range of its operation, and they can be tuned in a wide spectral range. With the combination of the Fourier transform spectrometer and the diode lasers as sources of coherent radiation, we compared the spectra measured with a FTIR spectrometer in its absorption arrangement using a 50 W halogen lamp, with a laser emission by a current with different amplitudes. This technique proved to be very promising for the detection of weak absorption signals in a narrow spectral range of laser emission. The main target of our work is focused on the modally characterization and the measurement of the basic properties (threshold current, spectral region of the laser emission, laser width and the area of tunability) of the three similar VCSEL diode based on GaSb matrix, which are emitting in the infrared region around 4250 cm^-1. We used FTIR spectrometer Bruker IFS 120 HR with the maximum resolution 0.0035 cm^-1 in the emission setup for the laser diagnostic research. The first measurement of the high resolution absorption spectra of several gases (methane, carbon monoxide and ammonia) has been achieved.