1. INTRODUCTION

With the growth of computing technology the need of high performance computers (HPC) has significantly increased. Optics has been used in computing for a number of years but the main emphasis has been and continues to be to page link portions of computers, for communications, or more intrinsically in devices that have some optical application or component (optical pattern recognition etc.)

Optical computing was a hot research area in 1980â„¢s.But the work tapered off due to materials limitations that prevented optochips from getting small enough and cheap enough beyond laboratory curiosities. Now, optical computers are back with advances in self-assembled conducting organic polymers that promise super-tiny of all optical chips.

Optical computing technology is, in general, developing in two directions. One approach is to build computers that have the same architecture as present day computers but using optics that is Electro optical hybrids. Another approach is to generate a completely new kind of computer, which can perform all functional operations in optical mode. In recent years, a number of devices that can ultimately lead us to real optical computers have already been manufactured. These include optical logic gates, optical switches, optical interconnections and optical memory.

Current trends in optical computing emphasize communications, for example the use of free space optical interconnects as a potential solution to remove ËœBottlenecksâ„¢ experienced in electronic architectures. Optical technology is one of the most promising, and may eventually lead to new computing applications as a consequence of faster processing speed, as well as better connectivity and higher bandwidth.

2. NEED FOR OPTICAL COMPUTING

The pressing need for optical technology stems from the fact that todayâ„¢s computers are limited by the time response of electronic circuits. A solid transmission medium limits both the speed and volume of signals, as well as building up heat that damages components.

One of the theoretical limits on how fast a computer can function is given by Einsteinâ„¢s principle that signal cannot propagate faster than speed of light. So to make computers faster, their components must be smaller and there by decrease the distance between them. This has resulted in the development of very large scale integration (VLSI) technology, with smaller device dimensions and greater complexity. The smallest dimensions of VLSI nowadays are about 0.08mm. Despite the incredible progress in the development and refinement of the basic technologies over the past decade, there is growing concern that these technologies may not be capable of solving the computing problems of even the current millennium. The speed of computers was achieved by miniaturizing electronic components to a very small micron-size scale, but they are limited not only by the speed of electrons in matter but also by the increasing density of interconnections necessary to page link the electronic gates on microchips.

The optical computer comes as a solution of miniaturizing problem. Optical data processing can perform several operations in parallel much faster and easier than electrons. This parallelism helps in staggering computational power. For example a calculation that takes a conventional electronic computer more than 11 years to complete could be performed by an optical computer in a single hour. Any way we can realize that in an optical computer, electrons are replaced by photons, the subatomic bits of electromagnetic radiation that make up light.

3. SOME KEY OPTICAL COMPONENTS FOR COMPUTING

The major breakthroughs on optical computing have been centered on the development of micro-optic devices for data input.

1. VCSEL (VERTICAL CAVITY SURFACE EMITTING LACER)

VCSEL (pronounced Ëœvixelâ„¢) is a semiconductor vertical cavity surface emitting laser diode that emits light in a cylindrical beam vertically from the surface of a fabricated wafer, and offers significant advantages when compared to the edge-emitting lasers currently used in the majority of fiber optic communications devices. The principle involved in the operation of a VCSEL is very similar to those of regular lasers.

There are two special semiconductor materials sandwiching an active layer where all the action takes place. 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.

[attachment=3071]

Technical Seminar on Optical Computing Technology






Introduction

Optical computing is the science of making computing work better using optics and related technologies
Some researchers use optoelectronic computing


Why Do We Need Optical Computers?
Rapid growth of the Internet
Network speeds currently limited by electronic circuits
Terabit speeds are required
Traditional silicon circuits have a physical limit


Silicon Machines¦

Types of Optical Computer
Optical Analog

These include 2-D Fourier transform or optical correlators, and optical
matrix-vector processors. 
Optoelectronics

In this type of computing device would be to shorten the pulse delay
in chips and other logic elements by using optical interconnections. 

MATERIALS FOR OPTICAL COMPUTER
Materials belong to the classes of phthalocyanines and polydiacetylenes. are used.
Phthalocyanines are large ring-structured porophyrins for which large and ultrafast nonlinearities have been

observed. These compounds exhibit strong electronic transitions in the visible region and have high chemical and

thermal stability up to 400C.
Subsequently, polydiacetylenes are among the most widely investigated class of polymers for nonlinear optical

applications. Their subpicosecond time response to laser signals makes them candidates for high-speed

optoelectronics and information processing.

MATERIALS FOR OPTICAL COMPUTER
How Does It Work?
Devices used for optical computing
Logic gates :
Logic gates are implemented optically by controlling the population inversion that occurs to produce lasing. A

controlling laser is used to control the population inversion thus causing switching to occur.
Holographic truth table
“ Destructive interference will light to be emitted or not based on phase relationship
Logic based on gratings
“ 1 is represented by vertical grating causing light
“ 0 is represented by horizontal grating causing darkness1



Devices used for optical computing
Holographic storage :
Holographic data storage has 4 components
Holographic material; thin film on which data is to be stored
Spatial Light Modulator (SLM); 2D array of pixels, each of which is a simple switch to either block or pass

light
Detector array; 2D array of detector pixels, either as Charge-coupled device (CCD) camera or CMOS detector

pixels to detect existence of light
Reference arm; arm carrying the laser source to produce the reference beam


Devices used for optical computing
Interconnections in optical computing
Optical interconnection technologies arerelatively mature
Fiber optic cables and optical transceivers are widely used
Applications of optical communications like fiber channel and computer networking are already being used.
Although there is a basic speed limitation is optoelectronic conversion delays
WDM is used to get around this limitation
Chip to Chip and On-Chip interconnection possibilities are still being examined
Promising but there are problems regarding dense organization of optical processing units

Devices used for optical computing

Devices used for optical computing
Smart Pixel Technology 
Different Approaches to Smart Pixels
Monolithic integration:
§         Materials incompatibility (III-V™s and Si)
§         Si-SiGe-Ge-GaAsto lattice matching and strain relief 

Hybrid integration:
§         Flip-chip bonding
§         Difficulty of optical access
§         Remove substrate prior to (epi-lift-off) or after integration
§         Use transparent substrate (Silicon-on-Sapphire)o
§         Use longer wavelengths (980 nm, 1310 nm)



Application of Optical Computing
Optical Computing In Communication
Wavelength division multiplexing
Optical Amplifiers & DWDM
Storage area network
Fiber Channel Topologies
Basic topologies
F C-AL (Fiber Channel Arbitration Loop):
Cost effective, low performance solution
Switched:
Better performance, more expensive
Hybrid topologies
Uses loops and switches as building blocks
Any interconnection network scheme can be realized



Application of Optical Computing
Optical Computing In VLSI Technology
Many researchers have been investigating suitable optical logic devices, interconnection schemes, and

architectures. Furthermore, optics may provide drastically new architectures to overcome some architectural

problems of conventional electrical computers.
Optical computing as expanders
The optical expander described utilizes high-speed and high-space-bandwidthproduct connections that are

provided by optical beams in three dimensions.


Whatâ„¢s Beyond the Optical Limit?
Quantum computing
Allows particles to be in more than one state at a time
Each particle in a quantum computer to hold more than one bit of information.
A quantum computer is, thus far, only a hypothetical machine
Expected between 2030 and 2050

CONCLUSION
Optics has been used in computing for a number of years but the main emphasis has been and continues to be to

link portions of computers, for communications, or more intrinsically in devices that have some optical

application or component.
Optical digital computers are still some years away, however a number of devices that can ultimately lead to

real optical computers have already been manufactured, including optical logic gates, optical switches, optical

interconnections, and optical memory.
The most likely near-term optical computer will really be a hybrid composed of traditional architectural design

along with some portions that can perform some functional operations in optical mode.

best of luck.......... da.............

presented by:
Sachidananda Panda

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[attachment=9101]
Optical Computing Technology
Introduction
 “Optical computing is the science of making computing work better using optics and related technologies”
 Some researchers use “optoelectronic computing”
Why Do We Need Optical Computers?
 Rapid growth of the Internet
 Network speeds currently limited by electronic circuits
 Terabit speeds are required
 Traditional silicon circuits have a physical limit
Types of Optical Computer
 Optical Analog
These include 2-D Fourier transform or optical correlators, and optical
matrix-vector processors.
 Optoelectronics
In this type of computing device would be to shorten the pulse delay
in chips and other logic elements by using optical interconnections.
 Optical parallel digital computers
These would use the inherent parallelism of optical devices along with digital electronics for flexibility.
 Optical neural computer
Neural computers compute in the sense that they have streams of input and output bits. They do not require anything resembling ordinary programming; if programming is done at all it is by dynamically changing the degree to which the individual nodes are connected.
MATERIALS FOR OPTICAL COMPUTER
 Materials belong to the classes of phthalocyanines and polydiacetylenes. are used.
 Phthalocyanines are large ring-structured porophyrins for which large and ultrafast nonlinearities have been observed. These compounds exhibit strong electronic transitions in the visible region and have high chemical and thermal stability up to 400C.
 Subsequently, polydiacetylenes are among the most widely investigated class of polymers for nonlinear optical applications. Their subpicosecond time response to laser signals makes them candidates for high-speed optoelectronics and information processing
A comparison of a scanning electron micrographs of 1 mm thick films of copperphthalocyanine deposited by physical vapor transport in the 3M PVTOS flight (STS-20) and ground control experiments
A comparison of a ground-grown polydiacetylene film with a microgravity-grown one.
How Does It Work?
 Photonic circuits
 Organic compounds
 No short-circuiting possible
 No heat dissipation
 Speed of light in photonic circuits will be close to speed of light in vacuum
 Light beams can travel in parallel
They can transfer data in parallel.

[attachment=9543]
OPTICAL COMPUTING TECHNOLOGY
ABSTRACT
Optical computing means performing computations, operations, storage and transmission of data using light. Instead of silicon chips optical computer uses organic polymers like phthalocyanine and polydiacetylene.Optical technology promises massive upgrades in the efficiency and speed of computers, as well as significant shrinkage in their size and cost. An optical desktop computer is capable of processing data up to 1,00,000 times faster than current models.
With the growth of computing technology the need of high performance computers (HPC) has significantly increased. Optics has been used in computing for a number of years but the main emphasis has been and continues to be to page link portions of computers, for communications, or more intrinsically in devices that have some optical application or component (optical pattern recognition etc.)
Optical computing was a hot research area in 1980’s.But the work tapered off due to materials limitations that prevented optochips from getting small enough and cheap enough beyond laboratory curiosities. Now, optical computers are back with advances in self-assembled conducting organic polymers that promise super-tiny of all optical chips.
Optical computing technology is, in general, developing in two directions. One approach is to build computers that have the same architecture as present day computers but using optics that is Electro optical hybrids. Another approach is to generate a completely new kind of computer, which can perform all functional operations in optical mode. In recent years, a number of devices that can ultimately lead us to real optical computers have already been manufactured. These include optical logic gates, optical switches, optical interconnections and optical memory.
Current trends in optical computing emphasize communications, for example the use of free space optical interconnects as a potential solution to remove ‘Bottlenecks’ experienced in electronic architectures. Optical technology is one of the most promising, and may eventually lead to new computing applications as a consequence of faster processing speed, as well as better connectivity and higher bandwidth.
APPLICATIONS:
1. High speed communications :The rapid growth of internet, expanding at almost 15% per month, demands faster speeds and larger bandwidth than electronic circuits can provide. Terabits speeds are needed to accommodate the growth rate of internet since in optical computers data is transmitted at the speed of light which is of the order of 310*8 m/sec hence terabit speeds are attainable.
2. Optical crossbar interconnects are used in asynchronous transfer modes and shared memory multiprocessor systems.
3. Process satellite data.
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.

[attachment=9994]
OPTICAL COMPUTING TECHNOLOGY
ABSTRACT
Optical computing means performing computations, operations, storage and transmission of data using light. Instead of silicon chips optical computer uses organic polymers like phthalocyanine and polydiacetylene.Optical technology promises massive upgrades in the efficiency and speed of computers, as well as significant shrinkage in their size and cost. An optical desktop computer is capable of processing data up to 1,00,000 times faster than current models.
With the growth of computing technology the need of high performance computers (HPC) has significantly increased. Optics has been used in computing for a number of years but the main emphasis has been and continues to be to page link portions of computers, for communications, or more intrinsically in devices that have some optical application or component (optical pattern recognition etc.)
Optical computing was a hot research area in 1980’s.But the work tapered off due to materials limitations that prevented optochips from getting small enough and cheap enough beyond laboratory curiosities. Now, optical computers are back with advances in self-assembled conducting organic polymers that promise super-tiny of all optical chips.
Optical computing technology is, in general, developing in two directions. One approach is to build computers that have the same architecture as present day computers but using optics that is Electro optical hybrids. Another approach is to generate a completely new kind of computer, which can perform all functional operations in optical mode. In recent years, a number of devices that can ultimately lead us to real optical computers have already been manufactured. These include optical logic gates, optical switches, optical interconnections and optical memory.
Current trends in optical computing emphasize communications, for example the use of free space optical interconnects as a potential solution to remove ‘Bottlenecks’ experienced in electronic architectures. Optical technology is one of the most promising, and may eventually lead to new computing applications as a consequence of faster processing speed, as well as better connectivity and higher bandwidth.
APPLICATIONS:
1. High speed communications :The rapid growth of internet, expanding at almost 15% per month, demands faster speeds and larger bandwidth than electronic circuits can provide. Terabits speeds are needed to accommodate the growth rate of internet since in optical computers data is transmitted at the speed of light which is of the order of 310*8 m/sec hence terabit speeds are attainable.
2. Optical crossbar interconnects are used in asynchronous transfer modes and shared memory multiprocessor systems.
3. Process satellite data.
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.

Submitted by
BHUNESHWAR PRASAD

---

[attachment=10191]
ABSTRACT
Computers have become an indispensable part of life. We need
computers everywhere, be it for work, research or in any such field. As
the use of computers in our day-to-day life increases, the computing resources that we need also go up. For companies like Google and Microsoft, harnessing the resources as and when they need it is not a problem. But when it comes to smaller enterprises, affordability becomes a huge factor. With the huge infrastructure come problems like machines failure, hard drive crashes, software bugs, etc. This might be a big headache for such a community. Optical Computing offers a solution to this situation.
Optical computing describes a new technological approach for
constructing computer's processors and other components. Instead of the current approach of electrically transmitting data along tiny wires
etched onto silicon. optical computing employs a technology called
silicon photonics that uses laser light instead. This use of optical lasers
overcomes the constraints associated with heat dissipation in today's
components and allows much more information to be stored and
transmitted in the same amount of space.
Optical computing means performing computations, operations,
storage and transmission of data using light. Optical technology
promises massive upgrades in the efficiency and speed of computers, as
well as significant shrinkage in their size and cost. An optical desktop
computer is capable of processing data up to 1,00,000 times faster than
current models.
INTRODUCTION
With the growth of computing technology the need of high performance
computers (HPC) has significantly increased. Optics has been used in computing for a number of years but the main emphasis has been and continues to be to page link portions of computers, for communications, or more intrinsically in devices that have some optical application or component (optical pattern recognition etc.) Optical computing was a hot research area in 1980's.But the work tapered
off due to materials limitations that prevented optochips from getting small enough and cheap enough beyond laboratory curiosities. Now, optical computers are back with advances in self-assembled conducting organic polymers that promise super-tiny of all optical chips.
Optical computing technology is, in general, developing in two directions.
One approach is to build computers that have the same architecture as present day computers but using optics that is Electro optical hybrids. Another approach is to generate a completely new kind of computer, which can perform all functional operations in optical mode. In recent years, a number of devices that can ultimately lead us to real optical computers have already been manufactured. These include optical logic gates, optical switches, optical interconnections and optical memory.
Current trends in optical computing emphasize communications, for
example the use of free space optical interconnects as a potential solution to remove 'Bottlenecks' experienced in electronic architectures. Optical technology is one of the most promising, and may eventually lead to new computing applications as a consequence of faster processing speed, as well as better connectivity and higher bandwidth.
NEED FOR OPTICAL COMPUTING
The pressing need for optical technology stems from the fact that today's
computers are limited by the time response of electronic circuits. A solid transmission medium limits both the speed and volume of signals, as well as building up heat that damages components.
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. So to make computers faster, their components must be smaller and there by decrease the distance between them. This has resulted in the development of very large scale integration (VLSI) technology, with smaller device dimensions and greater complexity. The smallest dimensions of VLSI nowadays are about 0.08mm. Despite the incredible progress in the development and refinement of the basic technologies over the past decade, there is growing concern that these technologies may not be capable of solving the computing problems of even the current millennium. The speed of computers was achieved by miniaturizing electronic components to a very small micron-size scale, but they are limited not only by the speed of electrons in matter but also by the increasing density of interconnections necessary to page link the electronic gates on microchips.
The optical computer comes as a solution of miniaturization
problem.Optical data processing can perform several operations in parallel much faster and easier than electrons. This parallelism helps in staggering computational power. For example a calculation that takes a conventional electronic computer more than 11 years to complete could be performed by an optical computer in a single hour. Any way we can realize that in an optical computer, electrons are replaced by photons, the subatomic bits of

can u please send me the details of the project..i mean the whole abstract,architecture if there,diagrams.

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