Ultrahigh relaxation oscillation frequency (up to 30 GHz) of highly p-doped GaAs/GaAlAs multiple quantum well lasers

We have demonstrated a relaxation oscillation frequency (fr) of up to 30 GHz in highly p‐doped (Be=1×1019 cm−3) GaAs/GaAlAs multiple quantum well (MQW) lasers grown by molecular beam epitaxy. This is the highest fr achieved at room temperature for III‐V semiconductor lasers. The high fr is attained by the large differential gain in the p‐doped MQW structure having a low threshold electron density resulted from the excess hole density in addition to the quantum size effect.