AlGaAs Optoelectronic Devices for Optical Communications

Abstract

This thesis describes several semiconductor injection laser diodes and related optoelectronic devices that can be used as light sources for optical communication systems, and develops the intrinsic electrical model of the laser diode. All the devices were grown from the GaAs-GaAlAs ternary system using the liquid phase epitaxy technique. The AlGaAs materials are very useful for the fabrication of both optical devices (sources and detectors) and conventional electronic components, due to their optical and electrical properties. The first device is the Translaser, a monolithically integrated heterostructure bipolar transistor with an injection laser. The next two types of devices possess bistable electrical characteristics. One is a laser-SCR switch, and the second type consists of multi-PN heterostructure devices. Each of the devices described above performs an electronic function, of modulating the light output of the laser associated with it. Finally, two types of low-threshold single-node laser diodes are presented. Their properties make them attractive candidates for sources in optical fiber communication systems. The first one is the Embedded Stripe Laser, and the second one is a new version of the Buried-Heterostructure laser, fabricated on semi-insulating substrates. An equivalent circuit of the laser diode is presented in the last chapter. This model provides a better understanding of the operation of the laser diode, which is particularly important in applications which involve its high frequency: operation with other electronic components and when a modification of its frequency response is needed.