1.3 μm InAsP p-type modulation doped MQW lasers grown by gas-source molecular-beam epitaxy

We investigated the effect of p-type modulation doping on the laser performance in 1.3 mu m InAsP compressively strained MQW lasers grown by gas-sourer molecular beam-epitaxy (GSMBE) for the first time. A sharp modulation doping profile of beryllium was confirmed by secondary ion mass spectroscopy. A very low threshold current of 6 mA was: obtained for buried heterostucture lasers doped with 5 x 10(18) cm(-3) of 300 mu m-long cavity with cleaved facets. By using p-type MD-MQW lasers. the gain coefficient was confirmed to increase by about 100 cm(-1) compared to undoped MQW lasers from the measurement of cavity length dependence of threshold current density. Further, differential gain was confirmed to increase by a factor of 1.34 from the relative intensity noise spectrum. (C) 1999 Elsevier Science: B.V. All rights reserved.