Optical computing

Computers use light to work.

Most computers use tiny bits of power to think. But light can move very fast. It can carry much more data. Scientists use lasers to make these light beams. These beams can help a computer do math.

Special crystals can help control the light. This helps the computer make choices. Using light could make computers much faster. It is a bright way to think!

Most computers use electricity to work. They use tiny parts called transistors to process data. Scientists are working on a new way to build computers. They want to use light instead of electricity. This is called optical computing.

Light can move very fast. It can also carry much more data than electricity. To do this, scientists use photons. Photons are tiny particles of light. In an optical computer, light beams do the work. Instead of electric transistors, these computers use optical transistors. These parts use special crystals to control light beams.

Using light could make computers much faster. One way to use light is to delay a signal. Light can travel through a fiber-optic cable. It can also be split into many rays. This helps the computer check many answers at the same time. Some scientists even use prisms and mirrors to solve math problems. This is a bright new way to think about computers!

Computers usually work by moving electricity through tiny parts. Scientists are exploring a different way called optical computing. This method uses light waves to process and store data. These light waves come from lasers or other light sources. Using light might allow for a higher bandwidth than electrons. Bandwidth is the amount of data that can move at once.

To make this work, scientists need an optical transistor. A normal computer uses electric transistors to handle information. An optical transistor uses special crystals to control light. These crystals have a non-linear refractive index. This means the brightness of incoming light changes the light that passes through. These parts can build logic gates to make a central processing unit.

Researchers have studied these ideas for many years. In 1986, Brenner and Huang wrote about optical architectures. NASA scientists also worked to improve this technology around the year 2000. Some people use light to solve hard math problems. One way is to delay a signal in a fiber-optic cable. This allows a computer to check many solutions at the same time.

There are many specific ways to use light for math. One method uses prisms and mirrors to sort different colors. Another way uses the way lenses bend light to solve equations. In 2007, Shaked and others solved a travel problem using light. Later, a team at Hewlett Packard Labs built a single chip. This chip had 1,052 optical components inside it.

Optical computing is still a very big challenge. Light waves do not interact with each other very easily. They usually need electrons in a material to help them interact. This can make the parts larger than electric ones. Many companies are working on this today. These include IBM, Microsoft, and Lightmatter. They hope to make computers faster and better using light.

Optical computing, also known as photonic computing, is a method of processing, storing, and communicating data using light waves. Instead of using electricity, these systems use photons produced by lasers or other light sources. For decades, researchers have seen promise in using photons to achieve a higher bandwidth than the electrons used in standard computers. Bandwidth refers to the capacity for data to move through a system. Most current research focuses on creating optical digital computer systems that process binary data. This could involve replacing traditional electronic parts with optical equivalents to create hybrid systems.

To build an optical computer, scientists must create an optical transistor. In a standard electronic computer, the transistor is the fundamental building block. An optical transistor achieves a similar function using crystal optics. These crystals possess a non-linear refractive index, which is a special property of certain materials. In these crystals, the intensity of incoming light can change the intensity of the light that passes through. This process mimics how current affects a bipolar transistor. These optical transistors can then be used to build optical logic gates. These gates are assembled to form the higher-level components of a central processing unit, or CPU.

Building a functional optical computing system requires four essential elements. First, it needs an optical processor to handle calculations. Second, it requires optical data transfer, such as fiber-optic cables. Third, it needs optical storage to hold information. Finally, it requires an optical power source, which is a light source. While light travels much faster than the drift velocity of electrons, there are significant technical hurdles. Light waves are electromagnetic waves, and they do not interact with each other easily. They typically require the presence of electrons within a material to interact. Because this interaction is weaker than electronic signals, optical components might require more power or larger dimensions.

There are several unconventional ways to use light to solve complex mathematical problems. One method involves using time delays to perform computations. This approach uses two main properties of light: it can be delayed by passing through optical fiber, and it can be split into multiple rays. By splitting light, a system can evaluate multiple solutions at the same time. For example, in a subset sum problem, light enters a start node and divides into rays. These rays travel through a graph-like structure of cables and splitters. The light is marked as it moves through nodes and arcs. A destination node then looks for specific fluctuations in signal intensity to determine if a solution exists.

Other specialized methods exist for different types of math. Wavelength-based computing uses prisms and mirrors to sort different colors of light. Each wavelength can represent a different value in a logic problem. Another method uses the natural properties of lenses to perform a continuous Fourier transform. This is useful for scientific applications like solving heat equations. In the 2010s, researchers also began focusing on on-chip integrated optics. This led to the development of photonic tensor cores. In 2025, a paper described a method called parallel optical matrix–matrix multiplication, or POMMM. This allows for tensor operations to be performed in a single shot of light at very high speeds.

History shows a long interest in these technologies. In 1986, researchers Brenner and Huang published work on optical architectures for digital computers. Around the year 2000, scientists at NASA worked to improve optical computing technology. In 2007, Shaked and colleagues used an optical correlator to solve the traveling salesman problem. More recently, researchers at Stanford, led by Yoshihisa Yamamoto, pioneered building Ising machines using photons. While Yamamoto first used lasers and mirrors, a team at Hewlett Packard Labs later integrated 1,052 optical components onto a single chip. This represents a major step in miniaturizing these complex systems.

Despite this progress, the future of optical computing remains a subject of debate. Critics point out that electronic transistors are currently very good at providing logic-level restoration and high-speed isolation at a low cost. For optical logic to compete in more than just niche areas, major breakthroughs in non-linear optical device technology are needed. Currently, many optoelectronic devices lose 30% of their energy when converting between light and electricity. This conversion also slows down the transmission of messages. However, all-optical computers could eventually eliminate these conversions, which would greatly reduce electrical power consumption.