An overview of the results of research on semiconductor quantum wells of the first kind is given, you GaAs (001) spread on singular substrates by molecular beam epitaxy (MBE). The cycle of the described works was based on the "pumping—probing" method with temporary resolution 0.13 picoseconds and reflection sensitivity 5 × 10^-6. Also described method for increasing the speed of operation of optical gates based on quantum wells, based on charge carrier tunneling between quantum wells; recovery times of linear reflection reaches 0.4 ps. Information on development of compact Yb: KYW laser with pulse duration up to 200 fs, with maximum average output power 2.5 W (optical pumping power 5 W) and with maximum frequency femtosecond pulse repetition 0.98 GHz. Optical shutter failure threshold is not less than 8.87 mJ/cm². This is double that of the commercial shutter.