These advantages have been known about for decades, but recent innovations, driven by investments from the telecoms industry, have finally started to make optical computing devices practical. In particular, breakthroughs in silicon photonics are making it possible to build sophisticated optical processors using the same technology as the existing chip industry.21
The most promising near-term application appears to be in AI. That is because optical processors are well-suited to carrying out operations known as matrix multiplications; these are fundamental to all deep learning algorithms.22 But photonic technology appears to be a fundamental building block that could also be used to build quantum computers, neuromorphic processors, memristors and even analogue computing devices.23242526 There are reasons for caution: catching up with and displacing decades of progress in silicon transistor technology remains an enormous engineering challenge, for instance. In addition, photonic chips normally rely on wavelengths of light measured in micrometres, making it unlikely that they could achieve the kind of miniaturisation found in silicon chips that already boast nanoscale features.