Amid the artificial intelligence boom, the world has been laser-focused on technologies like graphics processing units and memory chips. However, a quieter miracle has been unfolding in the mainland stock market.

Optical modules, which allow ultra-fast communications in data centres, have minted a new class of industrial upstarts.

In the past year, shares in Shenzhen-listed Zhongji Innolight, the world’s largest optical module producer, jumped tenfold. Smaller peers Eoptolink Technology and Suzhou TFC Optical Communication, also listed in Shenzhen, notched share-price gains of more than five times. And the combined market capitalisation of the three firms recently eclipsed that of baijiu distiller Kweichow Moutai – the long-standing champion of Chinese equities.

In the first quarter, Innolight and Eoptolink were the second and third favourite stocks among actively managed equity funds in the country, trailing only the world’s leading maker of electric-vehicle batteries, Contemporary Amperex Technology Ltd (CATL), according to financial information provider Wind. TFC ranked 12th, ahead of Ping An Insurance and chipmaker Cambricon Technologies.

Notably, Innolight and TFC have both recently announced plans to list in Hong Kong, further expanding their influence and footprint overseas.

What do the firms make?

Optical modules, also known as optical transceivers, convert electrical signals to optical signals, and vice versa, for high-speed data transmission in networking and AI infrastructure systems.