In an optical semiconductor package according to the present invention, the component bearing surface of the stem having an outline made up of opposed first and second circular-arc parts, a first straight-line part which connects each end of the first and second circular-arc parts and a second straight-line part which connects each other end of the first and second circular-arc parts. The head portion has a cylindrical shape and a hollow structure. When actuated, each valve cross-ports the system’s fluid flow from the valve’s inlet port to the system’s return line, thereby permitting all fluid flow and power to bypass the power drive motor.