Robust coupled-quantum-well structure for use in electrorefraction modulators

In this letter, an InGaAs/InAlAs coupled-quantum-well structure that is very robust to layer thickness and the compositional variations is reported. The robustness occurs because the structure's electrorefraction (ER) is based on the anticrossing of the two lowest energy light-hole wave functions. The structure is, thus, more appropriate for use in transverse magnetic modulators rather than in transverse electric modulators. The robustness of the structure is shown to be superior to that of a similar structure that has its ER effect based on the anticrossing of the two lowest, energy electron wave functions.