Written by James Bourne

Plenty of the tech press will muse on the idea that Moore’s Law – where the number of transistors in an integrated circuit doubles approximately every two years – is no more. Yet developments in photonics, as well as other components of the microelectronics stack, may have something to say about it. 

Jensen Huang, the CEO of NVIDIA, the world’s leading semiconductor company by market cap, has fuelled the most column inches in this respect with the presumed demise of Moore’s Law. As far back as 2017, Huang has made this prediction; indeed, ‘Huang’s law’, where the performance of graphics processing units (GPUs) will more than double every two years, has consequently entered the vernacular.  

In 2022, Huang said again that Moore’s Law was dead at a press Q&A for the NVIDIA online GTC22 conference. Responding to a question around pricing on the new generation of parts, Huang noted that “the ability for Moore’s Law to deliver twice the performance at the same cost, or the same performance [for] half the cost in every year and a half [is] over… completely over. 

“The future is about accelerated full stack,” Huang added. “Computing is a software and a chip problem. We call it a full stack challenge. We innovate across the full stack.” 

It is safe to say that not everyone agreed. “Maybe the lack of silicon improvements will force research into photonics?” one user on TechSpot wrote on an article regarding Huang’s latest proclamations. “If there was as much money going into photonics as there is silicon, we could have viable products within a decade.” 

Not everyone is calling the end game, however. Not long after Huang’s comments, in December 2022, Intel said its research showed the possibility of cramming more than a trillion transistors into chips by 2030. This includes developing ‘novel materials for 2D transistor scaling… including super-thin material just three atoms thick’, as well as advancements in 3D packaging technology with a new 10 times improvement in density. 

The company is still on track to achieve this goal. Sanjay Natarajan, senior vice president and general manager of Intel Foundry Technology Research, said in a recent feature for Photonics Focus that Intel was ‘still on the path to delivering one trillion transistors on a package by 2030.’ 

As Photonics Focus notes, there are applications for and aspects of photonics which will help maintain Moore’s Law. One such key application is in data centre networking. Writing for Photonics.com, Ana Gonzalez, vice president of business at iPronics, outlines the rationale. “With increasing bandwidth requirements driving the present and future of datacom and telecom, photonic technologies are well-positioned candidates to replace electronic technologies when electronics reaches its limit for a particular application,” Gonzalez wrote. 

“If these photonics platforms are to be the optimal solution to perform within the software environments of these fields, these systems will possess the qualities of programmability, adaptability, and flexibility.” 

Gonzalez argues that, thanks to advancements in programmable photonic integrated circuits (PICs), where light is distributed and rerouted under software control, software-defined photonics (SDP) will provide direct benefits to data centres, from self-healing capabilities, to adapting to signal changes instantly. 

Another element, as Photonics Focus points out, is photolithography. Photolithography is a key process in semiconductor manufacturing, whereby light is used to transfer patterns onto a silicon wafer. In March, it was reported that Chinese scientists had created a ‘breakthrough’ alternative method of generating light with a 193-nm wavelength. If the technology can be scaled – noting that it is a big ‘if’ – lithography tools could be produced to make chips using advanced process technologies. 

The clearest advantage of photonics over electronics is being able to transmit data over long distances without worrying about data bitrate, resulting in lower energy transmission. It is this angle which may be the most compelling, particularly as energy usage through AI continues to rise. Photonic computing is a solution which impacts Moore’s Law by ‘answer[ing] the call for increased compute speed, low energy density, and reduced chip heating’, as Nick Harris, CEO of Lightmatter, wrote in 2020. 

Harris’ argument feels even more prescient today. “The most cost-effective answer to cooling things down is to not generate energy in the form of heat in the first place,” he wrote. “That’s where the paradigm shift to photonic computing wins… providing a path to getting chip scaling and performance back on track with Moore’s Law while simultaneously reducing the environmental impact of the data centres needed to continue the pace of AI innovation.” 

For those in the photonics space, Moore’s Law appears to be alive and well. 

Want to find out more about topics like this? The Microelectronics UK event on September 24-25, will also be addressing PICs and their potential in the supply chain Pre-register your place today.