Hong Kong-listed optical communication stocks collectively declined, with Yangtze Optical Fibre and Cable (06869.HK) falling over 9%, Sunny Optical Technology (02382.HK) falling over 8%, Huiju Technology (01729.HK) falling over 7%, Cambridge Technology (06166.HK) falling nearly 6%, and Xizhi Technology-P (01879.HK) falling over 4%.