We have developed the expressions for terminal currents in transistor lasers (TLs) having a single quantum well (SQW) as well as multiple quantum wells (MQWs) of different well and barrier widths in the base by solving a continuity equation relating the bulk copyright density with the 2-D copyright density via virtual states (VS). The gain in the quantum well (QW) is obtained by consi... https://www.campicon.com/