Electricity and Control April 2023

INDUSTRY 4.0 + IIOT

Semiconductor photonics: more data, more quickly

As high-performance computing, artificial intelligence, machine learning algorithms and other technologies become increasingly data-hungry, hardware cannot always keep pace. In addition, the need for real-time assessments of moving data points – such as for accurate velocity-mapping of other objects in autonomous systems and facial recognition for security systems – is crucial to an increasingly hands-free society. UK-based research firm IDTechEx recently released a report titled: Semiconductor Photonic Integrated Circuits 2023-2033, which looks at the possibilities presented by developments in this field.

I DTechEx suggests that, generally speaking, the promise of semiconductor photonics can be summarised in just four words: more data, more quickly. Photonic integrated circuits compared to electrical systems Discussion around the effectiveness and applicability of photonic integrated circuits must be contextualised by comparing the system to its electrical-only counterpart, electrical integrated circuits. Most semiconductor chips today are entirely electrical; they are compact packages (most are measured in square millimetres) consisting of bil lions of transistors (‘on or off’ switches) that can be used to store and process data, and electricity is used to operate them. A photonic integrated circuit (PIC) uses light (pho tons being the quanta of light) to transmit data, although it will likely also include some electrical components, such as a laser diode source that is electrically pumped and emits photons as a result. Although the architecture of a PIC is slightly different to that of an electrical IC, PICs can and have been created by leveraging the same manufacturing processes as used for the more mature electrical IC industry. Just as silica and sim ilar materials act as effective dielectric insulators between the copper traces in electrical ICs, they can also confine and ‘guide’ light, in fibre or waveguide configurations. By virtue of

Potential markets for photonic integrated circuits.

[Source: IDTechEx]

their physical properties, photons do not experience resist ance in the same way that electrons do. Rather, photons can be lost via material absorption, scattering, or other effects, which can be mitigated by a careful choice of materials. When injection and propagation losses are suitably mitigat ed, photonic systems can enable long-distance communi cations of substantial amounts of data, where sending data via electrical means is unwieldy due to the resistance in the conductive material. The use of light to transmit and receive data has enabled a revolution in the communications indus try, one of the main industries continuing to develop products to enable higher data transmission rates. Light at the frontier of data One of the ways in which photonic systems are being developed in the communications industry is to address the input/output (I/O) bottleneck. This is where data is unable to be moved into or out of a chip/chiplet at the same or a faster rate than the rate at which processing occurs. Thus, a backlog is created in the data stream, where processing/ storage conducted in other chips/chiplets is stalled while they await the data. This is a significant problem for systems that deal with large amounts of potentially unstructured data, but require low latency to function, such as neural language programming algorithms. Several companies are working on optical I/O solutions that reduce latency, allow for high bandwidth, and keep power expenditure at a minimum. The IDTechEx report covers the global PIC market across six different application sectors, providing a 10-year

[Source: IDTechEx]

Four key market drivers for PIC development. These derive from growing data demands across multiple market segments and applications, such as communications and networking, AI/ML algorithm runs, and HPC.

4 Electricity + Control APRIL 2023