| Current fiber optic communication systems use individual laser emitters and photodiode detectors at either end of the optical fiber to transfer information. Bidirectional transmission therefore requires either two optical fibers, with each fiber using an emitter at one end and a detector at the other, or an emitter-detector pair that is coupled to each end of a single optical fiber using a beamsplitter. Obvious drawbacks to these transmission schemes are the relatively high coupling loss that is associated with beamsplitters and the added material cost of the second optical fiber. It is, however, possible to solve both of these problems with a dual-mode Modulator/Detector device that modulates an outgoing optical signal in one mode, and detects an incoming signal in the other.; This dissertation presents the development of a Schottky barrier electroabsorption Modulator/Detector device. This is the first demonstration of such a device. The dual-mode operation of this device relies on the Franz-Keldysh effect to alter the optical absorption properties of the device active area. The Modulator/Detector is designed to operate at a wavelength of 1.3 {dollar}mu{dollar}m to minimize the effects of optical absorption and dispersion in typical silica fibers. Liquid phase epitaxial growth of the GaInAsP/InP material system is used to fabricate this device. Significant experimental results include a reduction in the background doping level in GaInAsP through the addition of trace amounts of Yb to the growth melt, measurement of the Schottky barrier height for GaInAsP (E{dollar}sb{lcub}rm g{rcub}{dollar} = 0.95 eV), and performance testing of the Modulator/Detector device. |
