Search

Compressively strained, square potential profile GaInAsP quantum wells (QWs) with grown on InP substrates are useful to improve 1.55-mum lasers. A new approach is based on the creation of a linear variation of the bandgap within the well, through linear variations in the As concentration. Effective density of heavy hold band states is reduced in such V-shaped structures, and overlap between electron and hole wavefunction is thought to be higher than narrow abrupt-shaped QWs.

An analysis accounts for the leakage of electron envelope function from a multi-quantum well (MQW) layer and finds the attenuation ratio of the MQW optical intensity modulator for 1.55 micrometer wavelength. Results for a modulator using InGaAsP compounds show an attenuation ratio of 12.6 decibels with a small residual absorption of 3.1 decibels for well number of 7 and well width of 9 nanometers at an applied voltage of -1.5 volts. The results agree with experimental observations for low field regions and show that the electron wave function leakage is large even for low applied fields.