Apple Inc.
Integrated device for optical time-of-flight measurement

Abstract:

An optoelectronic device includes a semiconductor substrate and an optically-active structure, including epitaxial layers defining a lower distributed Bragg-reflector (DBR) stack, a quantum well structure with P- and N-doped layers disposed respectively on opposing sides of the quantum well structure, and an upper DBR stack. Electrodes are coupled to apply a bias voltage between the P- and N-doped layers. Control circuitry, disposed on the substrate, is configured to apply a forward bias voltage between the electrodes so as to cause the optically-active structure to emit an optical pulse through the upper DBR stack, and then to reverse the bias voltage between the electrodes so as to cause the optically-active structure to output an electrical pulse to the control circuitry in response to incidence of one or more of the photons, due to reflection of the optical pulse, on the quantum well structure through the upper DBR stack.