How Photonic Chips Work—and Why They May Replace Electronics

The Problem With Electrons

For decades, electronic chips have transmitted data as streams of electrons through copper wires. This approach powered the computing revolution—but it is hitting physical limits. As data volumes explode, copper interconnects generate more heat, consume more power, and lose more signal over distance. Inside modern AI data centers, these bottlenecks are becoming critical.

Photonic chips offer a fundamentally different approach: they process and transmit information using photons—particles of light—instead of electrons. The result is faster data transfer, lower power consumption, and the ability to handle vastly more information simultaneously.

How a Photonic Chip Works

A photonic integrated circuit (PIC) performs the same basic job as an electronic chip—moving and processing data—but uses light as its medium. The chip is built on a silicon substrate, typically in a silicon-on-insulator (SOI) configuration. A thin layer of silicon sits atop silicon dioxide, creating a refractive index contrast that traps and guides light through microscopic channels.

Three core components make this possible:

• Waveguides — sub-micrometre silicon channels that steer beams of light around the chip, functioning like optical wires.
• Modulators — devices that encode digital information onto a light signal by rapidly switching it on and off or shifting its phase.
• Photodetectors — components that convert optical signals back into electrical form so conventional processors can read the data.

Together, these elements form an optical circuit. A laser generates the light, modulators stamp data onto it, waveguides route it across the chip, and photodetectors read the result. Because photons travel at the speed of light with minimal energy loss, the entire process is inherently faster and cooler than pushing electrons through metal.

Why Silicon Matters

The breakthrough that made photonic chips practical is that they can be fabricated using the same CMOS manufacturing processes that produce conventional electronic chips. This compatibility leverages more than four decades and hundreds of billions of dollars of investment in semiconductor fabrication infrastructure, according to IEEE's photonics technical committee.

Rather than building entirely new factories, chipmakers can produce photonic components on existing production lines. This dramatically lowers costs and accelerates adoption compared to exotic alternatives like indium phosphide or lithium niobate photonics.

The AI Data Center Connection

The most urgent demand for photonic chips comes from AI data centers. Training large language models requires moving enormous volumes of data between thousands of processors at extreme speed. Copper interconnects inside these facilities are becoming a bottleneck.

According to research published in npj Nanophotonics, integrated photonics is "fundamental to unlocking the scalability and efficiency of next-generation AI data centers." Replacing electrical links with optical ones can deliver a tenfold increase in energy efficiency and up to 50 times more bandwidth, according to estimates from Cambridge Consultants.

One key innovation is co-packaged optics (CPO), which places the photonic chip on the same package as the electronic processor. By minimizing the physical distance between optical and electrical components, CPO reduces latency and power consumption. Companies like Google have already integrated optical circuit switches into their AI infrastructure to boost bandwidth between compute clusters.

Beyond Data Centers

Photonic chips are also finding applications in telecommunications, medical sensing, autonomous vehicles (where LiDAR systems use photonic circuits to map surroundings), and even quantum computing, where photons serve as qubits.

Researchers are also exploring new materials to expand what photonic chips can do. A team collaborating with Nobel Laureate Konstantin Novoselov recently demonstrated that arsenic trisulfide crystals can be permanently reshaped using simple laser light, potentially enabling photonic components to be manufactured without expensive cleanroom lithography, as reported by ScienceDaily.

What Comes Next

The silicon photonics market was valued at roughly $2.2 billion in 2024 and is projected to grow at nearly 30% annually, potentially reaching $28.75 billion by 2034, according to Precedence Research. The rollout of 5G and early development of 6G networks are adding further demand for high-speed optical interconnects.

Photonic chips will not replace electronic processors entirely—computation still requires electrons. But for moving data at speed and scale, light is proving hard to beat. As AI workloads grow and energy costs mount, the case for photonics is becoming less theoretical and more inevitable.