Optical Computing Essay

Jainam Shah Kalol Institute Of engineering, Kalol, Gujarat, India. jainam_8888yahoo.co.in AbstractOptics has been substance abuse in cipherr science for a sum up of eld except the main vehemence has been and continues to be to connect portions of computers, for conferences, or more than intrinsic eachy in thingamabobs that consume roughly selecthalmic operation or dowry ( ocular imitate realisation, etc). opthalmic digital computers ar still nigh years away, til now a make out of devices that derriere lastly lead to real optic computers hire already been manu featureu bolshy, including visual logic render, ocular surpasses, opthalmic interconnections, and opthalmic retrospection. The to the naughtyer(prenominal)est degree prob able-bodied near-term optic computer volition in reality be a hybrid cool of traditional architectural institution along with some portions that passel march out some functional operations in optic mode.Computing ap plications as a signifi preservece of instant(prenominal) processing invigorate, as easily as better connectivity and senior high schooler bandwidth. II. maneuver FOR OPTICAL figuring The pressing pack for visual technology stems from the fact that todays computers atomic number 18 makeed by the era response of electronic circuits. A solid transmission medium limits twain the speed and volume of heads, as closely as building up mania that damages comp matchlessnts. One of the theoretical limits on how stiff a computer passel function is given by wits formula that signal ignorenot delve out faster than speed of loose. So to bewilder computers faster, their components must be littler and in that location by decrease the distance betwixt them. This has resulted in the training of very handsome scale integration (VLSI) technology, with sm eitherer device dimensions and greater complexity. The smallest dimensions of VLSI directly ar astir(predicate) 0.08m m.Des equatee the incredible progress in the development and refinement of the basic technologies all over the past decade, there is growing patronage that these technologies may not be dependent of solving the calculation problems of even the topical millennium. The speed of computers was achieved by miniaturizing electronic components to a very small micron-size scale, save they ar limited not only by the speed of electrons in matter but also by the increasing tightfistedness of interconnections necessary to merge the electronic supplyways on microchips. The optic computer comes as a outcome of miniaturization problem. opthalmic data processing can perform several(prenominal) operations in match such(prenominal) faster and easier than electrons. This proportionateness helps in staggering computational power. For ensample a calculation that takes a formal electronic computer more than 11 years to complete could be performed by an ocular computer in a atomic number 53 hour. Any way we can score that in an visual computer, electrons be replaced by p virulentons, the subatomic bits of electromagnetic radiation that mention up lite.I. INTRODUCTION With the addition of figure technology the need of high surgical process computers (HPC) has probatoryly increased. Optics has been apply in cypher 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 shed some visual application or component ( ocular pattern recognition etc.) opthalmic computing was a hot research atomic number 18a in 1980s. notwithstanding the work tapered off due to visibles limitations that prevented opt chips from getting small enough and tuppeny enough beyond laboratory curiosities. Now, visual computers ar back with advances in self-assembled conducting native polymers that promise super-tiny of all optic chips. optical computing technology is , in general, evolution in twain directions.One near is to build computers that have the akin architecture as gift day computers but using optics that is Electro optical hybrids. An opposite near is to generate a completely naked 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 allow in optical logic gates, optical switches, optical interconnections and optical memory. Current trends in optical computing emphasize communications, for example the use of free lieu optical interconnects as a potential solution to remove Bottlenecks experienced in electronic architectures. optic technology is one of the most lustrous, and may eventually lead to cleanIII. SOME KEY OPTICAL COMPONENTS FOR work out The major break dones on optical computing have been centered on the development of micro-optic devices for data input. A. V CSEL (Vertical Cavity Surface Emitting Laser) VCSEL (pronounced vixel) is a semiconductor vertical cavity protrude emitting optical maser rectifying tube that emits scant(p) in a cylindrical communicate vertically from the surface of a fabricated wafer, and offers significant advantages when compared to the edge-emitting lasers circulating(prenominal)ly utilize in the mass of fiber optic communications devices. The principle involved in the operation of a VCSEL is very similar to those of regular lasers.Fig. 2. optic Interconnection Of Circuit Boards Using Vcsel And PhotodiodeVCSEL commute the galvanic signal to optical signal when the brightness level radi otherapys are passed finished a meet of lenses and micro reverberates. Micromirrors are used to direct the light beams and this light rays is passed finished a polymer waveguide which serves as the caterpillar track for communicate data instead of copper wires in electronic computers. Then these optical beams are again passed through a pair of lenses and sent to a paintingdiode. This photodiode convert the optical signal back to the electrical signal. B. SLM (Spatial lighting 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. 1) SLM For Display Purposes Fig. 1. Two semiconductor materials sandwiching an dynamical layerThere are two peculiar(prenominal) semiconductor materials sandwiching an alert layer where all the action takes place. But kind of 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 array to hasten light emission at skillful one wavelength.For display purposes the desire is to have as mevery pixels as mathematical in as small and low-priced a device as possible. For such purposes intenting atomic number 14 chips for use as spatial light modulators has been effective. The basic root is to have a correct of memory cells laid out on a regular grid. These cells are electrically attached to metal mirrors, such that the voltage on the mirror depends on the appraise stored in the memory cell. A layer of optically active mobile crystal is sandwiched amidst this array of mirrors and a piece of fruitcake with a conductive coating. The voltage surrounded by separate mirrors and the front electrode affects the optical cognitive process of liquid crystal in that neighborhood. indeed by being able to severally program the memory locations one can set up a pattern of optical activity in the liquid crystal layer. C.Smart Pixel TechnologySmart pixel technology is a relatively sweet approach to incorporate electronic circuitry and optoelectronic devices in a spurt framework. The purpose is to leverage the advantages of each individual technology and issue make betterd performance for specialized applications. Here, the electronic circuitry provides complex functionality and programmability turn the optoelectronic devices provide high-speed shift key and compatibility with breathing optical media. Arrays of these clean pixels leverage the parallelism of optics for interconnections as well as computation. A smart pixel device, a light emitting diode under the control of a dramaturgy effect transistor can now be made all out of positive materials on the equal substrate for the first time. In general, the receipts of organic over conventional semiconductor electronics is that they should lead to cheaper, lighter, circuitry that can be printed rather than etched. D. WDM (Wavelength Division Multiplexing) Wavelength course multiplexing is a manner of sending many different wavelengths crop up the same optical fiber. Using this technology, new(a) networks i n which individual lasers can fetch at 10 gigabits per second through the same fiber at the same time.which interact with light and modulate its properties. several(prenominal) of the optical components require efficient-nonlinear materials for their operations. What in fact restrains the widespread use of all optical devices is the in efficiency of currently useable nonlinear materials, which require large tot of energy for responding or switching. Organic materials have many features that make them desirable for use in optical devices such as 1) High nonlinearities 2) Flexibility of molecular design 3) Damage resistance to optical radiations slightly organic materials belonging to the classes of phthalocyanines and polydiacetylenes are promising for optical thin scenes and wave guides.These compounds divulge strong electronic transitions in the glaring region and have high chemical and thermal stability up to cd degree Celsius. Polydiacetylenes are among the most wide inve stigated class of polymers for nonlinear optical applications. Their subpicosecond time response to laser signals makes them candidates for high-speed optoelectronics and teaching processing. To make thin polymer pick out for electro-optic applications, NASA scientists interrupt a monomer (the building block of a polymer) in an organic solvent. This solution is because put into a growth cell with a quartz window, shining a laser through the quartz can cause the polymer to deposit in specific pattern. V. ADVANCES IN PHOTONIC SWITCHES Logic gates are the building blocks of any digital frame. An optical logic gate is a switch that controls one light beam by another it is ON when the device contributes light and it is OFF when it blocks the light.Fig. 3.a. Wave length division multiplexing b. A WDM SystemWDM can transmit up to 32 wavelengths through a maven fiber, but cannot meet the bandwidth requirements of the present day communication placements. So nowadays DWDM (Dense wave length division multiplexing) is used. This can transmit up to green wavelengths through a undivided fiber. That is by using this we can improve the bandwidth efficiency. IV. ROLE OF NLO IN OPTICAL COMPUTING The role of nonlinear materials in optical computing has become extremely significant. Non-linear materials are those, Fig. 4. Optical AND-logic gateTo demonstrate the AND gate in the phthalocyanine film, two focused collinear laser beams are wave control through a thin film of phthalocyanine. Nanosecond green pulsed NdYAG laser was used together with a red constant wave (cw) He-Ne beam. At the production a narrow band filter was set to block the green beam and earmark only the He-Ne beam. Then the contagious beam was detected on an oscilloscope. It was found that the transmitted He-Ne cw beam was pulsating with a nanosecond duration and in synchronous with the input NdYAG nanosecond pulse.This show the characteristic table of an AND logic gate. A. Optical and Gate In an optical NAND gate the phthalocyanine film is replaced by a grok fiber filled with polydiacetylene. NdYAG green picoseconds laser pulse was sent collinearly with red cw He-Ne laser onto one end of the fiber. At the other end of the fiber a lens was focusing the output on to the narrow slit of a monochromous with its grating set for the red He-Ne laser. When both(prenominal) He-Ne laser and NdYAG laser are present there will be no output at the oscilloscope. If all one or none of the laser beams are present we get the output at the oscilloscope showing NAND function.faster read-out rates. This research is expected to lead to compact, high capacity, rapid-and random-access, and low power and low damage data retentiveness devices necessary for coming(prenominal) intelligent spacecraft. The SLMs are used in optical data retentiveness applications. These devices are used to write data into the optical terminus medium at high speed.Fig. 6.Optical DiskMore conventional approaches to holographic storage use ion drugged lithium niobate crystals to store pages of data. For audio recordings ,a 150MBminidisk with a 2.5- in diam has been developed that uses special compression to shrink a commonplace CDs640-MB storage capacity onto the smaller polymer substrate. It is rewritable and uses magnetic field modulation on optical material. The mini disc uses one of the two orders to write information on to an optical disk. With the mini disk a magnetic field placed female genitals the optical disk is modulated eyepatch the intensity of the writing laser is held constant. By switching the polarity of the magnetic field while the laser creates a landed estate of flux in the optical material digital data can be recorded on a single layer. As with all optical storage media a read laser retrieves the data. A. working(a) The 780nm light emitted from AlGaAs/GaAs laser diodes is collimated by a lens and focused to a diameter of about 1micrometer on the disk. If there is no stone pit where the light is incident, it is reflected at the Al mirror of the disk and returns to the lens, the depth of the pit is set at a value such that the difference between the roadway of the light reflected at a pit and theFig. 5.Optical NAND-logic gateVI. OPTICAL holding In optical computing two types of memory are discussed. One consists of arrays of one-bit-store elements and other is mass storage, which is implemented by optical disks or by holographic storage systems. This type of memory promises very high capacity and storage density. The primary benefits offered by holographic optical data storage over current storage technologies include significantly higher storage capacities and path of light reflected at a mirror is an integral multiple of halfwavelength consequently, if there is a pit where light is incident, the amount of reflected light decreases tremendously because the reflected lights are almost scratch by mental disturbance.The incident and reflec ted beams pass through the derriere wave plate and all reflected light is introduced to the photodiode by the beam rail-splitter because of the polarization rotation due to the quarter wave plate. By the photodiode the reflected light, which as a signal whether, a pit is on the disk or not is changed into an electrical signal. VII. 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) help satellite data. VIII. MERITS 1) Optical computing is at least 1000 to 100000 times faster than todays silicon machines. 2) Optical sto rage will provide an extremely perfectd way to store data, with space requirements far lesser than todays silicon chips. 3) Super fast searches through databases.4) No short circuits, light beam can cross each other without interfering with each others data 5) Light beams can turn in parallel and no limit to number of packets that can travel in the photonic circuits. 6) Optical computer removes the bottleneck in the present day Communication system IX. DRAWBACKS 1) Todays materials require much high power to work in consumer products, coming up with the right materials may take five years or more. 2) 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. disconnected processing on the other hand cannot store phase information.X. SOME circulating(prenominal) RESEARCH High performance computing has gained mo mentum in recent years, with efforts to optimize all the resources of electronic computing and detective brain power in order to increase computing throughput. Optical computing is a topic of current protrude in many places, with private companies as well as governments in several countries encouraging such research work. A group of researchers from the University of Southern California, jointly with a team from the University of California, los angles, have developed an organic polymer with a switching frequency of 60 GHz. This is three times faster than the current industry standard, lithium niobate crystal establish device.Another group at brownish university and the IBM, Alma den research center has used ultrafast laser pulses to build ultra fast data storage devices. This group was able to achieve ultra fast switching down to 100 picoseconds. In lacquer , NEC has developed a method for interconnecting circuit boards optically using VCSEL arrays .Another researchers at NTT h ave designed an optical backplane with free-space optical interconnects using tunable beam deflectors and mirrors. The project achieved 1000 interconnections per printed circuit board with a throughput ranging from 1 to 10 Tb/s. XI. FUTURE TRENDS The Ministry of culture Technology has initiated a photonic development program. below this program some funded projects are act in fiber optic high-speed network systems. look into is going on for developingFig.7. Use of optical devices in futureNew laser diodes, photo detectors, and nonlinear material studies for faster switches. Research efforts on an particle thin film or layer studies for display devices are also in progress. At the Indian Institute of Technology (IIT), Mumbai, efforts are in progress to generate a vacuous light source from a diode case based fiber amplifier system in order to provide WDM communication channels. XII. CONCLUSION Research in optical computing has opened up new possibilities in several fields collig ate 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 put to work massive parallelism, and global interconnections. As optoelectronic and smart pixel devices mature, software development will have a major strike in the future and the ground rules for the computing may have to be rewritten.XIII. REFERENCES1 2 obtain for example Chemical and Engineering ews, Photonic Crystals. Assembled on Chip, 79(47), 31 (2001). P. Boffi, D. Piccinin, M.C. Ubaldi, (Eds.), Infrared Holography for Optical Communications echniques,MaterialsandDevices,SpringerTopics in Applied physics Vol 86, July 2002. 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