The Future of Computers - Optical Computers

An optical computer (also called a photonic computer) is a device that performs its computation using photons of visible light or infrared (IR) beams, rather than electrons in an electric current. The computers we use today use transistors and semiconductors to control electricity but computers of the future may utilize crystals and metamaterials to control light.

An electric current creates heat in computer systems and as the processing speed increases, so does the amount of electricity required; this extra heat is extremely damaging to the hardware. Photons, however, create substantially less amounts of heat than electrons, on a given size scale, thus the development of more powerful processing systems becomes possible. By applying some of the advantages of visible and/or IR networks at the device and component scale, a computer might someday be developed that can perform operations significantly faster than a conventional electronic computer.

Coherent light beams, unlike electric currents in metal conductors, pass through each other without interfering; electrons repel each other, while photons do not. For this reason, signals over copper wires degrade rapidly while fiber optic cables do not have this problem. Several laser beams can be transmitted in such a way that their paths intersect, with little or no interference among them - even when they are confined essentially to two dimensions.

Electro-Optical Hybrid computers

Most research projects focus on replacing current computer components with optical equivalents, resulting in an optical digital computer system processing binary data. This approach appears to offer the best short-term prospects for commercial optical computing, since optical components could be integrated into traditional computers to produce an optical/electronic hybrid. However, optoelectronic devices lose about 30% of their energy converting electrons into photons and back and this switching process slows down transmission of messages.

Pure Optical Computers

All-optical computers eliminate the need for switching. These computers will use multiple frequencies to send information throughout computer as light waves and packets thus not having any electron based systems and needing no conversation from electrical to optical, greatly increasing the speed.

The Future of Computers - Quantum nanocomputers

A quantum computer uses quantum mechanical phenomena, such as entanglement and superposition to process data. Quantum computation aims to use the quantum properties of particles to represent and structure data using quantum mechanics to understand how to perform operations with this data.

The quantum mechanical properties of atoms or nuclei allow these particles to work together as quantum bits, or qubits. These qubits work together to form the computer’s processor and memory and can can interact with each other while being isolated from the external environment and this enables them to perform certain calculations much faster than conventional computers. By computing many different numbers simultaneously and then interfering the results to get a single answer, a quantum computer can perform a large number of operations in parallel and ends up being much more powerful than a digital computer of the same size.

A quantum nanocomputer would work by storing data in the form of atomic quantum states or spin. Technology of this kind is already under development in the form of single-electron memory (SEM) and quantum dots. By means of quantum mechanics, waves would store the state of each nanoscale component and information would be stored as the spin orientation or state of an atom. With the correct setup, constructive interference would emphasize the wave patterns that held the right answer, while destructive interference would prevent any wrong answers.

The energy state of an electron within an atom, represented by the electron energy level or shell, can theoretically represent one, two, four, eight, or even 16 bits of data. The main problem with this technology is instability. Instantaneous electron energy states are difficult to predict and even more difficult to control. An electron can easily fall to a lower energy state, emitting a photon; conversely, a photon striking an atom can cause one of its electrons to jump to a higher energy state.

I promise to write a series of articles on quantum issues very shortly...

The Future of Computers - Mechanical nanocomputers

Pioneers as Eric Drexler proposed as far back as the mid-1980's that nanoscale mechanical computers could be built via molecular manufacturing through a process of mechanical positioning of atoms or molecular building blocks one atom or molecule at a time, a process known as “mechanosynthesis.”

Once assembled, the mechanical nanocomputer, other than being greatly scaled down in size, would operate much like a complex, programmable version of the mechanical calculators used during the 1940s to 1970s, preceding the introduction of widely available, inexpensive solid-state electronic calculators.

Drexler's theoretical design used rods sliding in housings, with bumps that would interfere with the motion of other rods. It was a mechanical nanocomputer that uses tiny mobile components called nanogears to encode information.

Drexler and his collaborators favored designs that resemble a miniature Charles Babbage's analytical engines of the 19th century, mechanical nanocomputers that would calculate using moving molecular-scale rods and rotating molecular-scale wheels, spinning on shafts and bearings.

For this reason, mechanical nanocomputer technology has sparked controversy and some researchers even consider it unworkable. All the problems inherent in Babbage's apparatus, according to the naysayers, are magnified a million fold in a mechanical nanocomputer. Nevertheless, some futurists are optimistic about the technology, and have even proposed the evolution of nanorobots that could operate, or be controlled by, mechanical nanocomputers.