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OPTICAL COMPUTERS

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Title: OPTICAL COMPUTERS


1
OPTICAL COMPUTERS
  • By, Under The
    Guidance of
  • Nirmal RaJ
    Asst . Prof. Nelanjana Bowmick
  • Abhishek B Mane

2
What is Optical Computer
  • An optical computer is a computer that uses
    photons in visible light or IR beams to perform
    digital computation .

3
EXAMPLES
  • Consider E-mail

.txt format
Fiber optic cables
Electronic To Photonic Converter
Optical Computers perform computations, operate,
store and transmit data using only light.
5
4
Why Optical Computers...?
  • In silicon computers, the speed of computers was
    achieved by miniaturizing electronic components.
  • It is also estimated that the number of
    transistor switches that can be put onto a chip
    doubles every 18 months.
  • So further miniaturization of size introduces
    several problems such as dielectric breakdown,
    hot carriers, and short channel effects etc.

5
Advantages...
  • Increase in the speed of computation.
  • Immune to electromagnetic interference.
  • Free from electrical short circuits.
  • Have low-loss transmission and large bandwidth.
  • Speed of light in photonic circuits will be close
    to speed of light in vacuum
  • Capable of communicating several channels in
    parallel without interference.
  • Possesses superior storage density and
    accessibility
  • No power loss due to excess of heating.
  • Life of the hardware of optical computer is more.

6
Parallel communication
7
Optical computation ?
  • Light in the place of Electron
  • Uses optical components
  • Transistors, logical gates etc. are simulated
    using optics.
  • All-optical components require a high level of
    laser power to function as required.
  • Send pulses of light instead of pulses of
    electricity

8
Optical Components...
  • VCSEL-vertical cavity surface emitting micro
    laser
  • VCSELs have high performance and low cost
    advantages
  • Emits light in a cylindrical beam vertically from
    the surface of a fabricated wafer
  • Low-cost potential because the devices are
    completed and tested at the wafer level

9
Optical interconnection of circuit using VCSEL
and photodiodes
  • VCSEL converts the electrical signal to optical
    using lens and micromirrors

10
  • Photonic Crystals- crystals designed to replace
    transistors in optical computers.
  • Optical nanostructures that are designed to
    affect the motion of Photons.

11
  • SLMs - Spatial light modulators , play an
    important role in optical processing, for
    inputting information on light beams, and
    displays.
  • A set of memory cells laid out on a regular grid
    and value in each cell contribute to manipulate
    the behaviour of optical activity.

12
Logical Gates Logic gates are the
building blocks of any digital system. An optical
logic gate is a switch that controls one light
beam with another. It is "on" when the device
transmits light, and "off" when it blocks the
light.
13
  • Smart pixels -Smart pixels, the union of optics
    and electronics
  • Expands the capabilities of electronic systems
    and enables optical systems with high levels of
    electronic signal processing.
  • Some examples
  • LED- Light emitting diode with FET- Field
    effect transistor.

14
Use of Optics in computing..
  • Use of optics in intercommunication
  • Here optical fibres are used communicate
    internally like communicating with peripherals
    etc.
  • the use of free-space optical interconnects as a
    potential solution to alleviate bottlenecks
    experienced in electronic.
  • Optical sorting and optical crossbar
    inter-connects are used in asynchronous transfer
    modes.

15
Few Examples
16
  • Use of optics in Memory storage-
  • Mass storage, which is implemented by optical
    disks or by holographic storage systems.
  • The primary benefits offered by holographic
    optical data storage over current storage
    technologies include significantly higher storage
    capacities and faster read-out rates.
  • A holographic memory can store data in the form
    of a hologram within a crystal.
  • The analog nature of these devices means that
    data can be stored at much higher density than
    data written by conventional devices.

17

Process of Memory Storage using Optical Computing
18
Current work and Improvements.
  • By NASA
  • The thin films being developed.
  • Can perform switching, signal processing and
    frequency doubling
  • NASA have developed and built all-optical logic
    gate circuits for data processing

THIN FILM TRANSISTOR
19
  • By IBM
  • IBM announced that its researchers have built a
    device capable of delaying the flow of light on a
    silicon chip, a requirement to one day allow
    computers to utilize optical communications to
    achieve better performance.
  • Almaden Research Center at IBM have developed
    ultrafast data storage devices that use laser
    pulses

20
  • At the University of Bristol in the UK
  • Researchers have made a prototype optical quantum
    computer chip and used it to perform a
    mathematical calculation for the first time.
  • Intel claims optical computing "milestone
  • Intel's hybrid silicon laser research has allowed
    it to transfer 50Gb/s down a single fibre-optic
    channel.Intel has made a breakthrough in optical
    connection technology with the world's first
    end-to-end silicon photonics connection, which
    the company claims "could revolutionise computer
    design, dramatically increase performance, and
    save energy."

21
Challenges...
  • Finding materials that can be mass produced
  • Practical limits of eight to eleven bits of
    accuracy-intensity fluctuations.
  • Computation is a nonlinear process in which
    multiple signals must interact to compute the
    answer.
  • Making photonic crystals is a difficult process.
  • Putting optical switches on computer chips.
  • Fabrication.

22
The Smallest Laser Ever Made
  • Surface-plasmon lasers could enable a new
    generation of computers based on nanophotonics

23
  • DRAWBACKS
  • Todays materials require much high power to work
    in consumer products, coming up with the right
    materials may take five years or more.
  • Optical computing using a coherent source is
    simple to compute and understand, but it has many
    drawbacks like any imperfections or dust on the
    optical components will create unwanted
    interference pattern due to scattering effects.
    Incoherent processing on the other hand cannot
    store phase information.

24
CONCLUSION
  • Optical technology promises massive upgrades in
    the efficiency and speed of computers, as well as
    significant shrinkage in their size and cost.
  • Even though pure Optical computer has many
    challenges hybrid opto-electrical computer can be
    expected very soon, and in near future pure
    optical computer too..

25
Thank You
26
QUESTIONS
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