On the optimization of InGaAs-InAlAs quantum-well structures for electroabsorption modulators

Several InGaAs-InAlAs multiple quantum-well structures grown by metalorganic vapor phase epitaxy (MOVPE), with various Ga content and quantum-well width, have been investigated for electroabsorption modulators (EAM's). The light-hole heavy-hole splitting, the chirp parameter, the insertion loss and the figure of merit /spl Gamma//spl Delta//spl alpha//F of the different InGaAs-InAlAs structures have been evaluated with photocurrent, photoluminescence, absorption and X-ray measurements. It was then possible to experimentally study the influence of different parameters of the multiple quantum-well structures on the device performance. The use of tensile strained barriers are believed to be responsible for the improvement in the figure of merit. Structures with unresolved light-hole and heavy-hole transitions, with negligible chirp, with adequate insertion loss and with extremely high values for /spl Gamma//spl Delta//spl alpha//F have been obtained, however, not simultaneously.