Communication devices, nonlinear optical

Main group oxides with three-dimensional stmctures or transition metal oxides with d° or d ° configurations are wideband gap materials and are colorless when pure. As such they may serve as transparent optical materials or hosts for such applications as lasers or luminescent materials when properly doped. Others that lack a center of symmetry may have ferroelectric or ferroic properties that make them useful for a variety of device applications. Some of these may have nonlinear optical properties so important to modem communication networks (see Sections 6.3 and 6.5 and see Luminescence and see Ferroelectricity). 

Material science interest focuses on potential applications of its specific electronic and band structure. Metal-like conductivities, semiconductor properties, photoconductivity and the nonlinear optical features of URPAC samples suggest devices for electromagnetic shielding, energy storage, microelectronics, optoelectronic and optooptical communication or optical computing. 

The calculation of the electric properties of individual molecules as found in an infinitely dilute gas has for long been of great interest to quantum chemists. This curiosity has been spurred in recent decades by the increasing importance of the communications industry in the world and the parallel need for materials having specific properties for electronic, optical, and other devices. In particular, the nonlinear-optical quantities, defined at the microscopic level as hyperpolarizabilities and at the macroscopic level as nonlinear susceptibilities, have played a... 

Current discussions of potential applications of nonlinear optical signal processing in computers (7), both general and special purpose, and in communications for functions such as switching, amplifying, and multiplexing are primarily focussed on devices for the manipulation of laser beams in thin transparent films. With particular reference to bistable optical devices, the fundamental physical mechanisms which provide limits on speed, power dissipation, and size of optical switching elements have been discussed (8). 

Chapter 2 focuses on an important property of macromolecules, i.e., nonlinear optical (NLO) behaviour, with promising applications in development of faster and highly performing communication devices such as computers and fiber optic telecommunications. An introduction to the basic physical principles that undergo... 

The arrival of practical fiber optic communication networks has strengthened the need for more-efficient devices which are capable of routing or modulating optical signals. Such devices often rely on nonlinear optical effects such as the Pockels and Kerr effects which are second- and third-order phenomena, respectively. These effects arise as a result of the electric-field expansion for the electric polarization in a nonlinear medium ... 

In the field of solid state physics, one of the most investigated materials is ferroelectric, which has important applications as memory switching [1-4], nonlinear optical communications [5], non-volatile memory devices [6, 7], and many others [8, 9]. Ferroelectrics have also emerged as important materials as (a) piezoelectric transducers, (b) pyroelectric detectors, (c) surface acoustic wave (SAW) devices, and (d) four-phase mixing doublers. Both lithium tantalate and lithium niobate appear to be promising candidates as the key photonic materials for a variety of devices (a) optical parametric oscillators, (b) nonlinear frequency converters, (c) second-order norrlinear optical material, and (d) holography, etc. Many of such devices include important nano-devices [9-11],... 

---