Mesastripe injection heterolaser with heat removal through the substrate

Continuous-wave losing was achieved at temperatures up to $70^\circ C$ in mesastripe $AlGaAs$ heterojunction lasers consisting of stripes 10-$\mu m$ wide (emission wavelength 835-845 nm) attached on the substrate side to a copper heat sink. This made it possible to achieve a thermal resistance not exceeding 40 K/W in spite of an increase in the length of the heat sink. Moreover, the diode assembly became easier and it was possible to eliminate completely the distortion in the angular distribution pattern. The minimum transverse current was 58 mA at $25^\circ C$ and the maximum power was up to 30 mW. Life tests showed only slight changes in the output power in a period of 450 h at $70^\circ C$.