09-07-2011, 03:45 PM
Integrated optics refers to realization and integration of planar optical devices. Examples of optical devices are, to name a few, are optical waveguides, switches, modulators, dividers, couplers, sources and detectors. These devices usually fall into two categories of active and passive elements. Examples of passive devices are optical waveguides and couplers. Materials of choice for passive devices are glass (Si02) with some appropriate impurities, silicon dioxide (Si02) on silicon and silicon nitride (Si3N4) Active devices themselves can be divided into categories of electro optic and electro-luminescent devices. Modulators and switches are good examples of electro-optical devices, where an electric signal influences the state of light traveling in the device. Gallium arsenide (GaAs) and Lithium niobate(LiNbO3)are electro-optic materials, either the polarization of the light is rotated or the light velocity is modified by application of an external electric field(or in some cased a magnetic field).light emitting diodes(LEDs)and laser diodes(LDs) are electro-luminescence devices where the electric power is transferred into an optical power. One of the goals of the integrated optics is to eliminate any individual component assembly and alignment procedures. Therefore it is highly desirable to integrate light sources, like solid -state lasers and LEDs with the rest of the optical circuit.
