Single steady frequency and narrow line width external cavity semiconductor laser

A single longitudinal mode and narrow line width external cavity semiconductor laser is proposed. It is constructed with a semiconductor laser, collimator, a flame grating, and current and temperature control systems. The one facet of semiconductor laser is covered by high transmission film, and another is covered by high reflection film. The flame grating is used as light feedback element to select the mode of the semiconductor laser. The temperature of the constructed external cavity semiconductor laser is stabilized in order of 10(-3)degreesC by temperature control system. The experiments have been carried out and the results obtained-the spectral fine width of this laser is compressed to be less than 1.4MHz from its original line-width of more than 1200GHz and the output stability (including power and mode) is remarkably enhanced.

Electroluminescence and photoluminescence of Si/SiGe self-assembly quantum dot structures

Comparative electroluminescence (EL) and photoluminescence (PL) measurements were performed on Si/Si0.6Ge0.4 self-assembly quantum dots (QDs) structures. The samples were grown pseudomorphically by molecular beam epitaxy, and PIN diodes for electroluminescence were fabricated. Assisted TEM pictures shows the SiGe self-assembly QDs are platelike. And it showed that the diameters of QDs are in range from 40nm to 140nm with the most in 120nm. Both EL and PL has a wide luminescence peak due to wide distribution of QDs dimensions. At low temperature (T=14K), EL peak has a red shift compared to the corresponding PL peak. Its full-width at half-maximum (FWHM) is about 97meV, a little smaller than that of corresponding PL peak. The reasons of position and FWHM changes of EL peak from QDs have been discussed.