Abstract: There is disclosed a transmission line switching apparatus comprising a coupling board having a first surface adapted to be connected a first line and a second surface adapted to be connected a second line, adjusting means having a line length adjusting unit for handling surplus portions of the second lines and switching means for changing the connection between the first and second lines, and partition means for dividing the second surface of the coupling board into a plural rows.

Abstract: An apparatus is provided that allows the tunability of a waveguide bench router with a silicon-based material. This is accomplished by adding a triangular shaped layer of hydrogenated amorphous silicon (a-Si:H) as an active region across the waveguide. By varying a current across the triangle, the refractive index of the layer will change causing a change to the delay of the signal going across the material. Thus eliminated are the need for Group III-V elements or Lithium Niobate as the tunable element, increasing the coupling efficiency and decreasing cost.

Abstract: The reflecting surfaces within the resonator are minimized in an unstable laser resonator having a radially-dependent output end reflection profile and a passive Q-switch so that the least possible competing resonator geometries can be formed. For this purpose, a saturable absorber foil can be provided as a passive Q-switch element mounted so as to be inclined with respect to the optical axis. Furthermore, it is advantageous to use an output reflector having highly precise parallel boundary surfaces and to align this output reflector with high precision parallel to the end surfaces which delimit the laser medium.

Abstract: An optical fiber composite ground wire according to the present invention has a metal protective tube containing a grooved conductive spacer. The optical fiber cyomposite ground wire is characterized by further including a water absorption tape 3 wound around the outer surface of a spacer 1 to partly expose the spacer 1, wherein the protective tube 2 is brought into direct contact with the spacer 1 partly exposed from the water absorption tape 3, thereby electrically connecting the spacer 1 to the protective tube 2.