When a company with US$15.5 million in annual revenue debuts on a stock exchange and its market capitalisation briefly hits US$10 billion, the obvious question is: what do investors know that the financials don’t show yet? In Lightelligence’s case, the answer is optical interconnect and the growing conviction that conventional copper wiring between AI chips is about to become a serious constraint. Lightelligence, the first mainland Chinese photonics chipmaker to go public in Hong Kong, saw its share price surge by nearly 400% in its trading debut on Tuesday.  The Shanghai-based company  opened  at HK$880, against an offer price of HK$183.2–the top of its marketed range–having raised HK$2.4 billion (approximately US$310 million) in its IPO. The retail tranche alone was oversubscribed nearly 5,785 times. What optical interconnect actually does To understand why investors are this enthusiastic, it helps to understand the problem Lightelligence is trying to solve.…