An occipital plate for use in an occipito-cervico-thoracic construct is mounted to a patient’s occipital bone. An optical waveguide unit includes protruding portions which are extendingly provided at portions of at least one of an undercladding layer and an overcladding layer, and the protruding portions are located and formed at predetermined locations with respect to a light transmitting surface of a core. If the connection is established, an online learning process is performed to monitor the handshakes between the client and the server, thereby constructing a virtual server. The process utilizes dimethyl ether under conditions of elevated temperature and pressure to dissolve the solid material. At least one of the first, second and third lenses is coated with a layer of optical film for filtering light.