Abstract: A light intensity attenuator and attenuating method is provided, by which a pulse-shaped optical surge can be attenuated and an optical signal component using desired light intensity can be output by using a simpler structural arrangement, and without using many optical components and circuits. In this method, an optical signal including a pulse-shaped optical surge component is received, and the optical signal is again output after the light intensity of the surge component is attenuated by a desired amount.

Abstract: An improved optical waveguide device having an optical waveguide for guiding a lightwave comprises, on a surface of a substrate having an electrooptical effect, at least a pair of electrodes composed of a hot electrode and a ground electrode which controls a guided lightwave, a buffer layer formed between the electrodes and the optical waveguide; further comprising an antistatic film which is formed on an upper surface of the buffer layer such that it comes into contact only with the hot electrode.

Abstract: An optical waveguide device usable as an optical wave-modulator and having a reduced DC drift includes a LiNbO.sub.3 substrate, an optical waveguide formed in a front surface portion of the substrate, a dielectric layer covering the front surface of the substrate and the optical waveguide surface, and an electrode system arranged on the dielectric layer, the dielectric layer comprising a matrix component consisting of an amorphous SiO.sub.2 and a doping element component consisting of Li and/or Nb; and having a refractive index lower than that of the amorphous SiO.sub.2 matrix free from the doping element component.

Abstract: A tuning fork type vibrator for an optical chopper in a photosensor, which vibrator oscillates at a single frequency. The vibrator comprises vibrating plates so disposed as to face each other with a predetermined spacing therebetween, and a stem portion obtained by bonding together bent portions located at one end of each of said vibrating plates.

Abstract: In a diffraction grating made of a single crystalline silicon substrate, one major plane thereof is provided with a plurality of asymmetric triangular grooves, each having a wall inclined by an angle .theta. with respect to the major surface so as to satisfy an equation.theta.=sin.sup.-1 m.lambda..sub.B /2Pwhere .theta. represents the blaze angle, P the pitch of the groove, .lambda..sub.B the blazing wavelength, and m the order of diffraction. The walls of each groove receiving incident light is covered with a metal coat.The diffraction grating is prepared by using a {hkl} plane (where h=k) inclined by .theta. with respect to the {111} plane of the single crystalline silicon as a major surface, and then anisotropic-etching the major surface through an etching mask having stripes having sufficiently smaller width than the grating constant. Preferably, following the anisotropic etching, isotropic etching is made for the major surface.

Abstract: In a diffraction grating made of a single crystalline silicon substrate, one major plane thereof is provided with a plurality of asymmetric triangular grooves, each having a wall inclined by an angle .theta. with respect to the major surface so as to satisfy an equation ##EQU1## where .theta. represents the blaze angle, P the pitch of the groove, .lambda..sub.B the blazing wavelength, and m the order of diffraction. The walls of each groove receiving incident light is covered with a metal coat.The diffraction grating is prepared by using a {hkl} plane (where h=k) inclined by .theta. with respect to the {111} plane of the single crystalline silicon as a major surface, and then anisotropic-etching the major surface through an etching mask having stripes having sufficiently smaller width than the grating constant. Preferably, following the anisotropic etching, isotropic etching is made for the major surface.

Abstract: A mechanical optical switching device has a plurality of input optical fibers coupled to the input side of the mechanical switching device for receiving incoming light beam signals. Individually associated with each optical fiber is an input collimating lens which is positioned to receive the incoming light beam and to convert it into parallel light beams. Optical path-switching means, having a uniform refractive index, are disposed at the rear or output of the input lens for switching the optical paths of the collimated parallel light beams emerging from the input lens means. A plurality of output optical fibers have individually associated output lenses for focusing the parallel light beams, after they have passed through the position controlled by the optical path-switching means.