A directional coupler comprises a coupler circuit board which is mounted substantially perpendicular to the surface of a parent circuit board. , whereas the optical fiber preform or optical fiber has a glass cooling rate of 4000\xb0 C. The top horizontal panel is adhered to the vertical panels by means of adhesive tapes to form a receptacle for inserting over a gift. The inner lens is thereby securely fixed, which makes it possible to improve optical precision. After a predetermined length of time to permit the thermosetting polymer to polymerize along the wall of the mold to form a wall of the desired thickness, gas is introduced into said mold at the opposite end to eject the central unpolymerized portion of the thermosetting polymer from the mold, leaving behind in the mold a hollow formed article. Each interlamination disk is disposed between at least two of the laminations and includes a plurality of interlamination flow passages that receive a cooling medium from the shaft and direct the cooling medium, via centrifugal force, through the rotor and onto the stator.