Hong Kong-listed optical communication stocks fell sharply in the afternoon, with Helio Technology-P (01879.HK) down nearly 8%, Comba Telecom (02342.HK) down more than 7%, Sunny Optical Technology (02382.HK) down nearly 4%, Lens Technology (06613.HK) down more than 3%, and InnoLight Technology (03308.HK) and others following suit.