Abstract: The present invention relates to an optoelectronic integrated circuit which includes a body of a group III-V semiconductor material containing a laser diode, a photodiode and/or field effect transistors. The body includes isolation regions extending partially therethrough which electrically isolate the laser diode from the photodiode and the field effect transistors. However, the isolation regions are at least partially transparent to light so as to allow some of the light generated by the laser diode to reach the photodiode. The laser diode, photodiode and/or field effect transistors are electrically connected by conductive patterns on the body so as to form a desired circuit for controlling the laser diode. The body defines a laser diode having a multiple quantum well active layer sandwiched between two cladding layers. The photodiode may also be formed by the active layer and cladding layers or can be formed by filling a trench in the body with a semiconductor material.