A lens assembly is used in a fiber-optic communication system, and includes a substrate and at least one lens unit formed on the substrate. The lens unit has first and second surfaces, a first light-transmissive region proximate to the first surface, a second light-transmissive region proximate to the second surface, a light attenuation region located between the first and second light-transmissive regions, and an optical axis passing through the first and second light-transmissive regions and the light attenuation region. The light attenuation region has at least one attenuation layer formed with multiple carbonized spots using a high-energy beam such that the light transmittance of the lens unit is not greater than 70%.