Ultra-high-speed strain-compensated MQW lasers with reduced carrier transport effect and enhanced differential gain

We theoretically investigated the optimum design of high-speed multiple-quantum-well (MQW) lasers operating at 1.55-/spl mu/m, and experimentally demonstrated a wide-bandwidth of 30 GHz from a strain-compensated InGaAlAs/InGaAsP MQW laser with 20 wells at a cavity length of 120 /spl mu/m In our calculations, various combinations of well and barrier materials are examined for lattice-matched, strained-layered, and strain-compensated (SC) MQW lasers with InGaAsP and InGaAlAs barriers. The bandgap wavelength for the barrier layers was varied from 1.1 to 1.3 /spl mu/m It was possible to eliminate the carrier transport effect and simultaneously achieve a large differential gain by using the InGaAlAs barrier layers for SC-MQW lasers. Experimental results showed a steady increase in the maximum relaxation oscillation frequency when the number of wells was increased from 10 to 20 and the cavity length was reduced from 350 to 120 /spl mu/m.