The document discusses optical computing technology as an alternative to traditional electronic computing. It notes that optical computing was researched in the 1980s but work tapered off due to materials limitations. Light is well-suited for computing due to its speed, ability to be manipulated, and suitability for parallelization. Optical computing could solve miniaturization problems and allow data to be processed in parallel. Key components discussed include vertical cavity surface emitting lasers, smart pixel technology, wavelength division multiplexing, and spatial light modulators. The document outlines some advantages and challenges of optical computing.

1. Optical computing
Technology
Vishnu.K.Narayanan
Es6 R.no:50
I.P.T&G.P.T.C Shoranur

2. INTRODUCTION
With the growth of computing technology the need of high
performance computers has significantly increased.
Optical computing was a hot research area in 1980’s.But
the work tapered off due to materials limitations i.e. Using
light, instead of electric power, for performing
computations.
 This choice is motivated by several features that light has:
•It is very fast.
•It can be easily manipulated
•It is very well suited for parallelization

3. Why we Use Optics for
Computing?
 One of the theoretical limits on how fast a computer
can function is given by Einstein’s principle that
“signal cannot propagate faster than speed of light”.
 To make computers faster, their components must be
smaller and there by decrease the distance between
them.
 Optical computing can solve miniaturization
problem.
 Optical data processing can be performed in parallel.
 In optical computing, the electrons are replaced by
photons

4. Why We Use OpTICs fOR COmpUTINg?
What’s wrong with What’s right with Optics?
electronics?
 Light doesn’t suffer
 Miniaturisation can lead
to cross talk. from the electronic time
 Speed of electrons in response.
matter.  No need for insulators.
 Solid medium limits  Optical communication:
both speed and
magnitude. • Multiplexing and different
 Build up to heat. wavelengths with no
 30 cm length of wire interference.
produces ~ 1 ns delay. • Low signal loss, large
 Low bandwidth bandwidth.
interconnections. • Compact, lightweight,
inexpensive

5. OPTICAL COMPUTER
 An optical computer (also called a photonic
computer) is a device that uses the PHOTONS in
visible light or infrared beams, rather than
electric current to perform digital computations.
 An optical computer, besides being much faster
than an electronic one, might also be smaller.
 Unlike transistors, transphasors can be built to
handle several incoming signals at once.

6. OPTICAL COMPUTER
 Bright flashes of laser light can be sent hundreds
of miles along fine strands of specially made glass
or plastic called OPTICAL FIBERS.

7. Optic Fiber cables made of glass or
plastic
Glass optic
fiber
Plastic optic
fiber

8. OPTICAL COMPUTER
 Instead of transistors, such a computer will have
TRANSPHASORS.

9. OPTICAL COMPUTER
• Beams of light can crisscross and overlap without
becoming mixed up, whereas crossed electric
currents would get hopelessly confused.

11. OPTICAL COMPUTER
• The arrangement of connections and switches
would not have to be flat, as in an electronic
computer. It could be placed in any direction in
space, allowing totally new designs in
information processing.

13. An Optical Chip

14. SOME KEY OPTICAL COMPONENTS FOR
COMPUTING
 VCSEL
 SMART PIXEL TECHNOLOGY
 WDM
 SLM

15. 1. VCSEL
(VERTICAL CAVITY SURFACE EMITTING
LASER)
 VCSEL(pronounced‘vixel’)is a semiconductor vertical
cavity surface emitting laser diode that emits light in a
cylindrical beam vertically from the surface of a fabricated
wafer.
 But rather than reflective ends, in a VCSEL there are
several layers of partially reflective mirrors above and
below the active layer.
 Layers of semiconductors with differing compositions
create these mirrors, and each mirror reflects a narrow
range of wavelengths back in to the cavity in order to
cause light emission at just one wavelength.

16. VERTICAL CAVITY SURFACE EMITTING LASER
850nm VCSEL

17. Optical interconnection of circuit
boards using VCSEL and
PHOTODIODE

18. 2. SMART PIXEL TECHNOLOGY
 Smart pixel technology is a relatively new
approach to integrating electronic circuitry and
optoelectronic devices in a common
framework.
 Here, the electronic circuitry provides complex
functionality and programmability.
 While the optoelectronic devices provide high-
speed switching and compatibility with
existing optical media.
 Arrays of these smart pixels leverage the
parallelism of optics for interconnections as
well as computation..

19. 3. WDM
(WAVELENGTH DIVISION
MULTIPLEXING)
 Wavelength division multiplexing is a method
of sending many different wavelengths down
the same optical fiber.
 WDM can transmit up to 32 wavelengths
through a single fiber, but cannot meet the
bandwidth requirements of the present day
communication systems.
 Nowadays DWDM (Dense wavelength
division multiplexing) is used. This can
transmit up to 1000 wavelengths through a
single fiber. That is by using this we can
improve the bandwidth efficiency.

20. WAVELENGTH DIVISION MULTIPLEXING

21. 4. SLM
(SPATIAL LIGHT MODULATORS)
• SLM play an important role in several
technical areas where the control of light on
a pixel-by-pixel basis is a key element, such
as optical processing and displays.
• For display purposes the desire is to have
as many pixels as possible in as small and
cheap a device as possible.

22. MERITS
 Optical computing is at least 1000 to 100000 times
faster than today’s silicon machines.
 Optical storage will provide an extremely optimized
way to store data, with space requirements far lesser
than today’s silicon chips.
 No short circuits, light beam can cross each other
without interfering with each other’s data.
 Higher performance.
 Higher parallelism.
 Less heat is released.
 Less noise.
 Less loss in communication.

23. DRAWBACKS
 Today’s 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.
 Optical components and their production is still
expensive.
 New expensive high-tech factories have to be
built .

24. APPLICATION
 High Speed Communication
Optical Cross Bar Inter Connect
Process Sattelite Data

25. Progress in Optical Computing
Recent optical devices created:
Optical logic gates
 optical switches
Optical interconnections
 optical memory
Switching device performance
Speeds of 10 -15 seconds
Power requirements one millionth of a
watt

26. FUTURE TRENDS
The Ministry of Information Technology has initiated a
photonic development program.
Under this program some funded projects are continuing in
fiber optic high-speed network systems.
 Research is going on for developing
New laser diodes
Photo detectors
Nonlinear material studies for faster switches.

28. CONCLUSION
Research in optical computing has opened up new
possibilities in several fields related to high performance
computing, high-speed communications. To design
algorithms that execute applications faster ,the specific
properties of optics must be considered, such as their
ability to exploit massive parallelism, and global
interconnections. As optoelectronic and smart pixel
devices mature, software development will have a major
impact in the future and the ground rules for the
computing may have to be rewritten.

29. Any Queries !!!!

30. THANK YOU…