Abstract: A digital photodetector circuit having a photosensing stage connected to a depletion mode field effect transistor forming an inverter stage, increased sensitivity is achieved by then coupling the output of the photo inverter to a second photo inverter whose photosensitive element serves as the active load of an enhancement mode field effect transistor in the inverter stage. The circuit is readily fabricated in integrated structures. The circuit performance may be adjusted for responsiveness to light sensitivity and to provide selectable electrical output signal level and impedance matching including bistable performance.

Abstract: A method for improving the current confinement capacity of a double heterojunction laser by using a high energy implantation of oxygen in the regions of an injection laser surrounding the active region of such laser so as to make such regions semi-insulating.