A GaInAsP/InP Fabry–Perot‐type buried‐heterostructure quantum well laser operating at 1.55 &mgr;m has been realized utilizing iron‐doped semi‐insulating InP around vertical mesas fabricated by reactive ion etching using methane and hydrogen. A maximum cw output power of 19 mW has been achieved on as‐cleaved chips of 300 &mgr;m length with a quantum efficiency of 21% per facet. Threshold currents lie between 20 and 25 mA. As low as 2 &OHgr; series resistance has been measured despite an ohmic contact area not exceeding that of the 2‐&mgr;m‐wide mesa. A 3 dB bandwidth of 7.5 GHz at 12 mW output power is obtained from the small‐signal frequency modulation measurements.