The materials and processing required for semiconductor laser diodes and GaAs integrated circuits are different and often incompatible. This has been primarily responsible for the relatively slow development of integrated optoelectronic/electronic structures. Therefore, it is important to develop a method for combining the two dissimilar technologies using materials and processes which do not place prohibitive restrictions on the performance or geometry of the optical and electronic devices. The laser-in-a-well technique has been developed to overcome many of the problems of monolithically integrating an AlGaAs laser diode with complex GaAs circuitry. Optoelectronic transmitters containing a transverse junction stripe laser, a driver FET and a 36 gate 4:1 multiplexer are in process. The ability of the laser-in-a-well technique to combine the TJS processing with the GaAs electronics has already been demonstrated with the on-chip testing of working multiplexers on wafers containing lasers.