Photonic chips use light, rather than electricity, to move and process information. Instead of relying on electrons flowing through wires, these chips guide tiny packets of light, known as photons, through microscopic structures etched into a chip.
The appeal is straightforward. Light can carry large amounts of data with low loss and minimal interference, making photonic chips attractive for applications where speed, bandwidth, and energy efficiency matter. Electronic chips, which rely on electrons moving through silicon, remain essential for logic and control, but photonics offers a different way to handle data-heavy tasks.
Rather than replacing electronics entirely, photonic chips are increasingly used alongside them, each doing what it does best.
Lighting the way: how photonic chips work
Photonic chips process information by manipulating light as it travels through waveguides built into the chip. These waveguides act like optical highways, directing photons through components such as modulators, filters, and detectors.
By adjusting properties including wavelength, phase, and intensity, the chip can encode and transmit information with high precision. Multiple data streams can also travel at the same time using different wavelengths of light, allowing a single waveguide to carry far more information than an electrical wire.
Electronic chips work very differently. They process information using electrical signals created by electrons, the negatively charged particles that move through carefully engineered silicon structures. These signals switch transistors on and off to perform calculations and move data around a processor.
Both approaches are highly refined, but they are optimised for different jobs.
Material world: what photonic chips are made of
Electronic integrated circuits are built almost entirely on silicon. Photonic integrated circuits, or PICs, are more varied, using different materials depending on the function required.
Several platforms are widely used.
Indium phosphide PICs can generate, amplify, control, and detect light directly on the chip. This makes them well-suited to optical communications and sensing, where integrated lasers are essential.
Silicon nitride PICs are known for their wide spectral range and very low optical losses. These characteristics make them useful in applications such as spectrometry, biosensing, artificial intelligence, and some quantum systems.
Silicon photonics is best described as a technology platform rather than a single material. It combines silicon-based photonic components, often alongside materials such as silicon nitride, with standard CMOS fabrication processes. This compatibility allows photonic circuits to be manufactured using existing semiconductor infrastructure and integrated closely with electronic chips.
Made like microchips, but with a twist
The fabrication of photonic ICs looks familiar to anyone used to electronic chip manufacturing. Techniques such as photolithography, etching, and material deposition are used to define features on wafers at very small scales.
The challenge lies in precision. Light is sensitive to tiny imperfections, so waveguides and optical components must be fabricated with extremely tight tolerances. This is one reason why material choice and process control are so important in photonics.
Why bother with light?
The main advantages of photonic chips are bandwidth, energy efficiency, and signal integrity.
Electronic chips generate heat as electrons encounter resistance while moving through circuits and as transistors switch states. Managing this heat is one of the biggest challenges in modern processors.
Photonic chips, by contrast, guide light through optical waveguides that do not suffer from electrical resistance. While photonic systems still consume power, particularly for light sources and control electronics, they can move large volumes of data using less energy per bit.
Light is also immune to electromagnetic interference, which helps maintain signal quality at high data rates. This makes photonics particularly effective for moving data over short and medium distances, such as between processors or across data centre infrastructure.
Another key benefit is parallelism. By using multiple wavelengths of light at the same time, photonic chips can transmit many data streams simultaneously, increasing overall throughput without increasing physical complexity.
Where photonic chips shine
Because of these characteristics, photonic chips are especially attractive in data centres, where energy use and heat management are constant concerns. They are also widely used in telecommunications, medical diagnostics, sensing, and emerging quantum technologies.
As demand for computing performance grows alongside pressure to reduce energy consumption, interest in PICs continues to increase. Industry groups estimate that the photonic chip market could reach hundreds of millions of units by 2030, with longer-term potential extending well beyond that figure.
Electronics is not going away, but in a world that moves more data every year, light is becoming a very useful partner.
