Researchers use lasers to break down computer speed barriers

If you've ever wished for a faster phone, computer, or Internet connection, you've had personal experience of reaching the limits of technology. But there might be help on the road.

 

For the past few decades, scientists and engineers like me have been working to develop faster transistors, which are the fundamental electronic components of modern electronics and digital communication technologies.

 

These efforts are based on a type of material called a semiconductor, which has special electrical properties. Silicon is perhaps the best known example of such a material.

But about a decade ago, scientific efforts reached the speed limit of semiconductor transistors. The researchers simply couldn't get electrons to move faster in these materials.

 

One way engineers are trying to get around the speed limits inherent in moving electricity through silicon is by designing shorter physical circuits - essentially making the distance electrons travel shorter.

 

Increasing the computing power of a chip boils down to increasing the number of transistors. However, even if researchers could make transistors very small, they would not be fast enough for the faster processing and data transfer speeds that people and businesses need.

 

The goal of my research group's work is to use ultra-fast laser pulses in free space and fiber optics to develop faster methods of moving data. The laser travels through the fiber with almost no loss and the noise level is very low.

 

In our latest study, published in Science Advances in February 2023, we take a step in this direction by demonstrating that it is possible to use laser systems equipped with optical transistors that rely on photons rather than voltage to move electrons and transmit information much faster than current systems and more efficiently than previously reported optical switches.

 

Ultrafast optical transistor

At the most basic level, digital transmission involves turning signals on and off to represent 1s and 0s.

Electronic transistors use voltage to send this signal: when the voltage induces electrons to flow through the system, they emit a signal; When voltage-induced electrons flow through the system, they emit a signal; When no electrons are flowing, the signal is zero. This requires a source to emit electrons and a receiver to detect them.

 

Our ultrafast optical data transmission system is based on light rather than voltage.

 

Our research group is one of many conducting optical communication research at the transistor level - the building blocks of modern processors - to overcome the limitations of current silicon.

 

Our system controls reflected light to transmit information. When light hits a piece of glass, most of it will pass through, although a small portion may reflect. This is the glare you feel when you're driving into the sun or looking through a window.

 

We use two lasers fired from two sources to pass through the same piece of glass. One beam is constant, but its transmission through the glass is controlled by the second beam.

 

By using a second beam to change the properties of the glass from transparent to reflective, we can start and stop the transmission of a constant beam, thus very quickly switching the light signal from on to off and back again.

 

In this way, we can change glass properties much faster than current systems can send electrons. As a result, we can send more on and off signals (zeros and ones) in less time.

 

How fast are we talking?

Our research has taken the first step in transferring data up to a million times faster than we do with typical electronic devices.

For electrons, the maximum speed at which they can transmit data is nanoseconds, billionths of a second, which is very fast. But the optical switch we built is able to transfer data a million times faster in just a few hundred attoseconds.

 

We are also able to transmit these signals securely so that an attacker attempting to intercept or modify the message will fail or be detected.

 

Using a laser beam to carry the signal, and adjusting its signal strength with another laser-controlled glass, means that information can not only travel faster, but also over longer distances.

 

For example, the James Webb Space Telescope recently transmitted stunning images from far out in space.

These images are transmitted by optical communication from the telescope to a base station on Earth at a rate of "on" or "off" every 35 nanoseconds.

 

Laser systems like the one we are developing could increase transmission rates by a factor of a billion, allowing faster and clearer exploration of deep space and faster revealing of the secrets of the universe. One day, computers themselves may run on light.

 

Source: Laser Network