AI-generated summary
As traditional electronic computing approaches its physical limits—where increasing speed relies on adding more processor cores—photonic computing emerges as a promising alternative. Unlike electronics, which use negatively charged electrons flowing through metals and suffer from resistance, heat, and inefficiencies due to electron collisions, photonic computing harnesses massless photons, or particles of light, to process information. Photons can travel through optical fibers without interacting or losing energy, enabling faster, more efficient data transmission and potentially faster computation.
Photonic computing, particularly photonic quantum computing using pulsed lasers, aims to leverage these properties for processing data rather than just transmitting it. However, detecting and counting photons accurately poses a significant challenge since they move at light speed and lack mass, making current photon sensors less effective than electronic detectors. Despite this, advancements continue, with the goal of surpassing electronic computing speeds. Photonic technology is envisioned to integrate with existing silicon-based memory and electronics, creating hybrid systems that capitalize on the strengths of both. Much like USB-C improved connectivity without revolutionizing device design, photonics may drastically boost processing speeds while maintaining familiar computing infrastructures. Over time, photonic components could become prevalent in computers and mobile devices, potentially leading to a future dominated by photonic quantum hybrids, although miniaturization and stability hurdles remain.
Computing has a huge challenge because it is rapidly approaching the physical limits under which it can continue to operate at an accelerated rate
It’s becoming increasingly difficult to double computing power, and increasing speed already means including more cores in parallel. This barrier will have a detour thanks to quantum computing, but it will achieve a partial substitute thanks to photonic computing based on pulses of light.
What is photonic computing and what makes it different from electronics?
To understand photonic computing, it is first important to stop and think about electronic computing, that is, the one that is used daily. Electronics comes from electron, that negatively charged particle of the atom that moves through a metal. All computers, including a smart watch, mobile phone or thermostat, think with electrons moving from one side to the other.
But this poses major technical problems. When an electron travels through a wire, it doesn’t travel straight, but rather looks more like a pinball in which the electron hits the atoms and other electrons it encounters. These blows produce miscalculations, slow down technology, and produce heat. That’s why processor chips get very hot, and they get hotter the more operations they do.
Photonic computing is a complete game-changer because the photon lacks mass. This is why we use it in fibre optics. We can cram thousands of photons of information into glass tubes, send them miles away, and have them not interact with each other or step on each other. The goal of photonic computing is to use these properties not only to send information, but to process it.
How Photonic Computing Works
There are several types of photonic computing. The most advanced is photonic quantum computing, which consists of making calculations using what is called “pulsed laser”. In essence, it is a laser that emits particles of light in pulses instead of continuously. The barrier? Detecting and counting photons is much more complicated than counting electrons, precisely because of its characteristics of being massless or traveling at the speed of light.
It’s not that we don’t have sensors capable of detecting photons. After all, fiber optics work like that. But you need to identify on the order of 100 photons every few microseconds to start talking about effective computing capable of surpassing electronic computing. And it is not close. We need a minimum resolution of 50 photons and we are at 20 in ideal laboratory conditions; although at specific times important milestones have been achieved.
Is it possible to combine photonic computing with systems such as quantum or silicon?
Although it is not a perfect analogy, the change from electrons to photons is similar to changing cars for bicycles to improve efficiency: the road, the rules of the road or the zebra crossings will still be there and are integrable both in the transition and in future computing.
Thus, photonic computing is trying to integrate a technology of sending information at the speed of light with a support of silicon-based memories, so that when the technology becomes commercial, it is very likely that solid-state disks combined with silicon chips will continue to be used, not unlike how it was changed from HDD to SSD while maintaining the structure of the processors.
You have to think about photonics technology the way you think of USB-C as a component: it’s changed nothing and it’s changed everything. It has not been a fundamental change, but it has been a notable improvement. The leap from electronics to photonics uses other scales, but it will not change the way computers, power cables or displays work. What it will do is multiply the processing speed drastically.
Hybrid systems that combine photonics and electronics
It is likely that for a few decades we will observe hybrid electric-photonic systems, which in fact already exist. The Internet is a hybrid system: information is processed with electrons inside chips and sent with photons inside fiber optic cables. What will happen is that fiber optics, lasers and photon detectors will become a fundamental part of the operation of computers.
And it is possible that in time photonics will constitute practically all computers, something complicated with quantum technology that requires sub-zero temperatures and high stability. How will all this technology be hybridized? The current electron cloud will probably be replaced by a photonic quantum hybrid that processes the information away from the screen, and this will be quickly sent to mobile devices, which will have photonic components if they can be miniaturized. The latter is not easy.
