04-04-2011, 04:13 PM
PRESENTED BY-
VAIBHAV DESHWAL
PHOTONICS.ppt (Size: 1.07 MB / Downloads: 158)
“PHOTONICS”
INTRODUCTION
The science of photonics includes –
Generation
Emission
Transmission
Modulation
Signal processing
Switching
Amplification
Detection
Sensing
Its goal was to use light to perform functions that traditionally fell within the typical domain of electronics, such as telecommunications, information processing, etc.
Photonics is related to quantum optics, optomechanics, electrooptics, optoelectronics and quantum electronics
History
Photonics as a field began with the invention of the laser in 1960.
Photonics use light to perform functions that fell within the typical domain of electronics, such as telecommunications, information processing, etc.
Developments followed optical fiber and erbium -doped fiber ampifier,
Components
Generator-. Photonics commonly uses semiconductor light sources like LEDs, superluminescent diodes and lasers
Other light sources include fluorescent lamps ,CRTs, and plasma screens.
Amplifier
Optical amplifiers used in optical communications are erbium-doped fiber amplifiers,
Semiconductor optical amplifiers,
Raman amplifiers
Andoptical parametric amplifiers
Transmission media
Glass fiber or plastic optical fiber can be used to guide the light along a desired path.
Optical fibers allow for transmission distances of more than 100 km
Detector
Photodetectors detect light.
Photodetectors range from very fast photodiodes for communications applications over medium speed charge coupled devices (CCDs)
Modulation
Modulation of a light source is used to encode information on a light source.
Modulation can be achieved by the light source directly.
One of the easiest examples is to use a flashlight to send Morse code.
Crystals!!!
These are new type of crystals displaying unusual and attractive properties with interaction with light
Crystals made up of SiO2
Photonics vs Electronics
Electronic transistors will be replaced.
10 times less heat produced.
Processing speed increased 100 times.
Coherent beams unlike electric currents pass through each other without interfering
Electrons repels while photons do not
Bio-photonics
Biophotonics can be used to study biological materials
Optical coherence tomography.
Diffuse optical imaging and tomography.
NANOPhotonics
Study of behaviour of light on nanometer scale
Interaction of light at sub wavelength scales
Holography
Holographs are 3-D storage device
Holographic versatile discs are made with upto 4Tb memory
Holds importance in entertainment
Photonics in communication
Can pack more wavelengths in an optical fiber so that the transmission bandwidth is increased
Technology behind 5G.
Photonic Computing
Use photons rather than electrons.
Optical transistors are used.
Photonic logic is created.
Switching is obtained using nonlinear optical effects.
Other Applications
Information processing
Lighting
Metrology
Spectroscopy
Medicine
Military technology
Laser material processing
Visual art
Agriculture
Robotics
Construction
Aviation
Entertainment
Disadvantages
Waveguides and fibres are harder to use than wire.
The components are more expensive.
Spurious reflections are much more troublesome.