Analysis And design of electrooptic modulators with planar metal Electrodes

Several articles [1-4] were published to review both the history and thefundamentals of integrated optics. Optical communication systems are basedon three principle directions; the first direction is the optical fiber analysis andfabrication where it acts as a propagation medium for guiding optical wavesbecause the atmospheric variations cause undesirable changes in the opticalcharacteristics of the path from instant to instant. The second direction is thelaser source and its modem technology. The third direction is the integratedoptical waveguides and its application for constructing the optical devicessuch as; modulators, switches, filters, directional couplers, ... etc. toward thedesign of integrated optics.The area of integrated optics has been concerned with studying thephenomenon of light guided along and controlled by thin dielectric films orstrips. The wavelengths of interest are mostly between 0.1~ and 10 urn. Forwavelengths much greater than 1 0 urn, Le. in the millimeter region andbeyond, metallic wave-guiding techniques of the microwave variety haveprovided a more efficient technology. For wavelengths around 0.1 urn orsmaller, the absence of suitable sources and the presence of large absorptionand scattering losses impose limitations on the practical use of the waveguiding effects. But the modem laser diodes have been used as optical sourcesthat have been fabricated using GaInAsPIInP at wavelength 1.55 Jll11. So, theuseful range of operating wavelengths can be considered between 0.5 urn to1.7~.Voltage induced optical waveguide (one type from the four opticalwaveguides fabrications) is formed” by placing planar electrodes onelectrooptic waveguides, as shown in Fig. 1.1.