Abstract: A highly efficient power amplifier is composed of (1) two microwave divide/through switches, (2) two power amplifiers, connected with the two microwave divide/through switches, to amplify the signal power transmitted from the first microwave divide/through switch, and (3) a half-wavelength transformer, connected to an output terminal of one of the power amplifiers, to delay the phase of the amplified signal by a half-wavelength.

Abstract: The microwave DPDT switch according to the present invention is composed of (1) a branch line coupler having three gaps at the branch lines among two input ports and two output ports, and (2) three SPST switches locating at the three branch line gaps to transmit input signals to the output ports.

Abstract: Disclosed is a push-pull type micromachined microwave switch using torsion springs and a lever fabricated using a surface micromachining technique so that it operates at a low operating voltage.

Abstract: The present invention relates to an optical coupler 2.times.2 optical switch which can efficiently shorten the length of device by employing a cantilever and a movable optical waveguide and a method for optical switching with the optical coupler 2.times.2 optical switch. An optical coupler 2.times.2 optical switch of the present invention comprises: an optical coupler in which two fixed optical waveguides are provided on a substrate; an optical waveguide positioned between the fixed optical waveguides, which is moved up and down; and, a cantilever which is linked to the optical waveguide to move the optical waveguide up and down by the voltage applied to electrodes. Since the coupling length of the optical coupler(22) is changed depending on the distance between the fixed optical waveguides(21, 21') and the optical waveguide(23), length(D) of the optical, coupler(22) can be shortened to a great extent compared to the prior art optical coupler 2.times.

Abstract: The present invention relates to an optical coupler sensor employing a fixed optical waveguide and a movable optical waveguide which allows detection of every small physical quantities and their changes with a high sensitivity, and a process for preparing the same. The optical coupler sensor of the present invention comprises: a fixed optical waveguide formed on a substrate and disposed along a predetermined path. A movable optical waveguide is linked to a cantilever formed on the substrate, which is moved up and down by an external force. The moveable waveguide is disposed outside of the predetermined path.