Optical computers – Applications and challenges

Optical computer

An optical computer (also known as a photonic computer) is a computer that manipulates, stores, and transmits data using light rather than electricity (i.e., photons rather than electrons). It is a device that performs digital computations by using photons in visible light or infrared (IR) beams rather than electric current.

Photons and electrons have fundamentally different physical properties, and researchers have attempted to use these differences to create computers with greater performance and/or capabilities than electronic computers.

Electric current moves at only about 10% of the speed of light. This constrains the rate at which data can be exchanged over long distances and is one of the factors that prompted the development of optical fiber. By leveraging some of the benefits of visible and/or infrared networks at the device and component levels, a computer that can perform operations ten or more times faster than a conventional electronic computer could be developed someday.

Optical computing can be used to perform a variety of operations on signals. Several processing operations have proven to be more efficient with optical techniques than their electronic counterparts. These include Fourier transforms, convolution, correlation, and spectrum analysis. However, optical signal processors are inflexible compared with electronic computers.

Optical computing can be applied in several areas, including:

Application-specific devices

Devices such as synthetic aperture radar [SARI optical transistor, optical turing machine, antiballistic missile (ABM), and optical correlators use the principles of optical computing.

Digital communication

Fiber-optic communications, fiber-optical local area networks, and digital communications have all evolved due to optical computing, with fiber optic data transmission becoming commonplace. Optical fibers enable optical interconnections and devices. They are EMI-resistant and have largely replaced metallic wired media. Optic computing technology has no rival in telecommunications with optical fibers and cables, wavelength-division multiplexing (WDM), optical amplifiers, and switches. The ultimate goal is a “photonic network.”

Digital optical computing

To compete effectively with digital electronic computers, much research has been directed toward digital optical computing. The foundation of this application is a digital computing scheme. Information is represented by discrete signals and processed similarly to digital electronics. As a result, digital optical computing is well suited to collaborating with current electronic technologies.

Integrated Optics

This is appealing due to its high switching speed potential and compatibility with fiber-optic communication links. It is essentially an optical analog of electronic integrated circuits on a planar scale. Integrated optics technology can create planar arrays of guided-wave structures, electro-optic devices, sources, and detectors. Integrated optics devices are capable of the same logic and signal processing as semiconductor chips. Massive parallel processing, medical imaging, and optical supercomputer are some of the other applications.


The main advantage of optical computing is the numerous advantages that optical interconnections and optical integrated circuits have over their electronic counterparts. Among the benefits of optical computing are:

  • Optical computing is a minimum of one thousand to a hundred thousand 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.
  • Superfast searches through databases.
  • Light inherently has a large information capacity. Compared with radiofrequency or microwaves used in conventional communication, light has thousands to millions of times information capacity.
  • No short circuits, the light beam can cross each other without interfering with each other’s data.
  • Lightweight beams will travel in parallel and have no limit to the variety of packets within the photonic circuits.
  • The optical computer removes the bottleneck in the present-day communication system.


Optical computing systems differ significantly from electronic systems. As electronics approaches its natural technical limits, optics stands alone in providing massive parallelism. Optical computing allows for non-von Neumann architectures with various interconnection and communication mechanisms.

The fact that computation is a nonlinear process in which multiple signals must interact to compute the answer is a significant challenge for optical computing. As an electromagnetic wave, light can only interact with another electromagnetic wave when electrons are present in the material. This interaction is much weaker for electromagnetic wave light than for electronic signals in a traditional computer. As a result, the processing elements for an optical computer require higher power and larger dimensions than those for a conventional electronic computer based on transistors.