Photonics is the transmission, control, manipulation and storage of datausing photons (the basic building blocks of light).The unique characteristics of photonic devices create an additionaldimension energy saving and larger communication distances. Inaddition, photonic devices are less sensitive to interference and haveunique physical characteristics.
A Light-emitting Diodes is a semiconductor light source. LEDs areused as indicator lamps. In many devices, and are increasingly usedfor lighting. .LED is often small in area (less than 1 mm2 ) .It presents many advantages over bright light sourcesincluding lower energy consumption, longer life time,Smaller size and fast switching .
LEDS are poor diodes usually made from gallium arsenide. With theproper voltage and current it will emit photons at some variablefrequency in small visual spectrum whereby it can visually be seen withour eyes in difference colors in the visual spectrum.
Photodiodes are PN junction diodes designed specifically to prove thephotoelectric effect. This means the device show the junction region ofthe PN diode to incoming photons which results in conducting thetransfer of electrons across the junction. 1-The active area, i.e., the light-sensitive area . 2-The maximum allowed photocurrent (usually limited by saturation). 3-The dark current (The current through the photodiode in the absence of light, when it is operated in photoconductive mode). 4-The photocurrent divided by optical power –related to the quantum efficiency, dependent on the wavelength .
A photodiode is a p-n junction ,When a photon of sufficient energystrikes the diode, it excites an electron, thereby creating a free electrons(and a positively charged electron hole). This mechanism is also knownas the inner photoelectric effect .
A laser diode is a component that converts an electrical signalinto a corresponding light signal.A laser diode a semi conductor device that produces coherent radiationin the visible or infrared (IR) spectrum when current passes through it.1- Small size and weight: A typical laser diode measures less than onemillimeter across and weighs a fraction of a gram.2- Low current, voltage, and power requirements3- Low intensity: A laser diode cannot be used spectacular purposes.such as burning holes in metal, bringing down satellites.
Laser diode is completely solid state and do not require fragile glasselements.It is formed by doping a very thin layer on the surface of a crystalwafer. The crystal is doped to produce an n-type region and a p- type region, one above the other, resulting in a p-n junction, or diode.A power supply for energizing the laser diode pump source.
Molhum Mohammed Hamed 115002Mohammed Essam Mohammed 115057Mohammed Abdo Mohammed 115059Amr Aidross Abdullah 115081Ziad Ahmed 115084
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