Fibre optics optical communications

Quaternary Ga In j.As jPj, grown on InP is of major importance to fibre-optic communications. In quaternary compounds, both the gap and the lattice constant can be tailored by changing the chemical composition. In thick layers, in order to avoid the generation of strain-induced defects, care must be taken in adjusting the ratio of x and v to maintain the lattice-matched composition x = 2.2v. The available gaps range from 1.34 eV in InP to -0.75 eV in... 

Ledwith. A. Glasses for Fibre Optic Communications, Reviev (University of Wales) 15 (RefSeasonsSpring 1988). 

It has been known for many years [19] that water can be incorporated into silica in the form of hydroxyl groups which have a characteristic absorption in the infrared. This was a problem encountered in the early days of fibre optics communications technology and solved by excluding water from the processing atmospheres. This water can be readily introduced by high temperature annealing in water vapour and removed by heating in a water-free atmosphere. 

Quaternary Ga In P grown on InP is of major importance to fibre-optic communications. In quaternary... 

Indium phosphide is used in optoelectronics and radiation sources, but at present takes third place in importance after silicon and gallium arsenides. Semiconductor lasers based on In Gai. As, operating at 1.3 and 1.55 mm, have been extensively developed as the light sources for fibre optic communication systems. The formation of such compositions can be represented as vapour phase reactions (12.400). 

The growing use of fibre optic cables has stimulated the demand for ancillary components to facilitate connections and other requirements. One interesting development at Toronto University in Canada has been the production of a new hybrid plastic which can produce light at the wavelengths used in fibre optic communications thus paving the way for an optical computer chip. 

For optical transmission, tire parameters of greatest importance are attenuation (i.e. loss) and material dispersion. In effect tliey define tire limits of tire optical communication system. Loss, due to absorjDtion and scattering, limits tire lengtlis between tire transmission nodes. In transmission quality fibre, tire loss is in units of decibels per kilometre. 

As an alternative to planar waveguiding structures we report here the fabrication of crystal cored fibres in which it is possible to maintain uniform guide dimensions over long lengths. These fibres with organic crystal core material having large second order non-linearity could be used for miniaturization of visible laser sources and realization of parametric amplifiers for optical communications. 

A. L. Harmer, Fibre optic sensors for offshore process control instrumentation, Proc. Optical Fibre Sensors Conference (OFS 86), Informal Workshop at Tusukuba Science City, 1986, VII. Pub Institute of Electronics and Communication Engineers of Japan, Tokyo, 1986. 

Modem switchgear and variable speed controllers are available with micro-computer based control, protective and indication facilities. These can communicate between each other and to external networks by such links as fibre optics and digital hardwire networks. 

What neither they nor Dariat quite appreciated were the myriad number of physical interfaces between the neural strata and Valisk s communications net. The tube trains and the starscraper lifts were the most obvious examples, but every mechanical and electronic utility system had a similar junction, a small processor nodule which converted fibre optic pulses to nerve impulses and vice versa. And Magellanic Itg not only built Valisk s communications net, it also supplied ninety per cent of the counterrotating spaceport s electronics. A fact which even fewer people were aware of was that every company processor had a back-door access function hardwired in, to which Rubra alone had the key. 

The transmission of light along thin fibres of glass, plastic or other transparent materials is referred to as fibre optics. Data are carried by a series of pulses of light encoded so that information can be stored and retrieved. In this brief survey, the properties of the materials used in the fibre will be outlined. The engineering of an optical communications system can be explored by reference to some of the sources listed in the Further Reading section. 

The spreading out of a pulse in an optical communications fibre is called ... 

Amplification of signals in optical communications fibres uses ... 

---