Abstract: In a Raman gain measuring method according to the invention, a CW (continuous wave) probe light is input into a Raman amplifying medium. A Raman pumping light being binary-intensity-modulated at a modulation factor is generated. The Raman pumping light is input into the Raman amplifying medium. Two index values regarding to AC component and DC component are extracted from the probe light having propagated through the Raman amplifying medium. The Raman gain of the Raman amplifying medium is determined from the two index values and the modulation factor.

Abstract: In a Raman gain measuring method according to the invention, a CW (continuous wave) probe light is input into a Raman amplifying medium. A Raman pumping light being binary-intensity-modulated at a modulation factor is generated. The Raman pumping light is input into the Raman amplifying medium. Two index values regarding to AC component and DC component are extracted from the probe light having propagated through the Raman amplifying medium. The Raman gain of the Raman amplifying medium is determined from the two index values and the modulation factor.

Abstract: A four fiber ring network optical switching circuit capable of realizing the bridge function at times of the span switching and the ring switching economically by a very compact structure is disclosed. A four fiber ring network optical switching circuit is formed by a 10×8 optical matrix switch having ten input ports and eight output ports, and two branching elements adapted to branch each one of two optical signals among eight optical signals that are inputs of the four fiber ring network optical switching circuit, into two identical optical signals, and to enter the two identical optical signals into two input ports of the 10×8 optical matrix switch such that the eight optical signals are entered into the ten input ports of the 10×8 optical matrix switch as ten optical signals.

Abstract: A four fiber ring network optical switching circuit capable of realizing the bridge function at times of the span switching and the ring switching economically by a very compact structure is disclosed. A four fiber ring network optical switching circuit is formed by a 10×8 optical matrix switch having ten input ports and eight output ports, and two branching elements adapted to branch each one of two optical signals among eight optical signals that are inputs of the four fiber ring network optical switching circuit, into two identical optical signals, and to enter the two identical optical signals into two input ports of the 10×8 optical matrix switch such that the eight optical signals are entered into the ten input ports of the 10×8 optical matrix switch as ten optical signals.

Abstract: At least a one conductivity type nanostructure PS layer whose thickness is controlled, and the opposite conductivity type nanostructure PS layer and a one conductivity type mesostructure PS layer arranged in contact with both these sides are comprised. Since the one conductivity type nanostructure PS layer is formed by anodizing the non-degenerate n-type crystalline silicon layer whose thickness is established in advance, the thickness which can provides a maximum luminescence efficiency can be obtained correctly. Then a semiconductor light emitting device whose luminescence efficiency is improved without increasing an unnecessary series resistance is provided. An inexpensive semiconductor light emitting device having a large light emitting area can be provided, since silicon wafer having a large diameter can be employed as the material for light emission.

Abstract: The present invention provides a semiconductor memory capable of retaining information after removing a power supply and of storing information with an optical input. A memory cell is comprising an n-InP substrate, a first semiconductor (n-InGaAs) layer, a second semiconductor (i-InGaAs) layer, a third semiconductor (p-InGaAs) layer, a fourth semiconductor (i-InGaAs) layer and a fifth semiconductor (n-InGaAs) layer. The first to fifth semiconductor layers are stacked in this order on the n-InP substrate. A bias voltage is applied between the n-InP substrate and the fifth semiconductor layer to control a height of a TBD formed in the above multi-layer structure so that carriers may move and electrons can be stored in one of the second and fourth semiconductor layers.

Abstract: At least a one conductivity type nanostructure PS layer whose thickness is controlled, and the opposite conductivity type nanostructure PS layer and a one conductivity type mesostructure PS layer arranged in contact with both these sides are comprised. Since the one conductivity type nanostructure PS layer is formed by anodizing the non-degenerate n-type crystalline silicon layer whose thickness is established in advance, the thickness which can provides a maximum luminescence efficiency can be obtained correctly. Then a semiconductor light emitting device whose luminescence efficiency is improved without increasing an unnecessary series resistance is provided.

Abstract: Nitrogen-doped group II-VI compound semiconductor thin film manufacturing method and apparatus which are applicable to an MOVPE process. The group II-VI compound semiconductor thin film manufacturing method according to the present invention is characterized by the use of osmium as a catalyst to activate nitrogen molecules. The growth device according to the present invention has a construction wherein a nitrogen gas introducing pipe for blowing a nitrogen gas against a semiconductor substrate is disposed in a reaction chamber for growing the group II-VI compound semiconductor thin film by the MOVPE process and the osmium is disposed between the semiconductor substrate and the nitrogen gas introducing pipe.

Abstract: A method which permits the growth of high-quality crystals of n-type II-VI compound semiconductors containing sulfur, by suppressing the reaction of a group III or VII element as a dopant with a group II material at low temperature. A raw material gas containing an organometallic material of the group III or organic material of the group VII is premixed with a raw material gas containing organic sulfur material, then the premixture is mixed with a raw material gas containing an organometallic material of the group II, and the mixture is used to grow a crystal of an n-type II-VI compound semiconductor on a semiconductor substrate by a metal organic vapor phase epitaxial growth method.

Abstract: An optical logic element is disclosed which performs an XOR operation through utilization of the high-speed property of light. On each branched waveguide of a Mach-Zehnder interference type optical waveguide there is provided a phase modulating element whose refractive index undergoes a change when it is irradiated by light. The interference type optical waveguide is adapted to provide different optical output levels when the refractive index changes of the phase modulating elements are both zero or a predetermined value and when they differ from each other. Thus, the optical logic element is capable of performing the XOR or XNOR operation at an ultrahigh speed.

Abstract: A spatial light modulator is disclosed, in which a low dark resistance single-crystal plate is used which is formed of Bi.sub.12 MO.sub.20 (where M is Si, Ge or Ti) or similar type crystal, doped with phosphorus (P) in the range of 0.03.ltoreq.P.ltoreq.0.2 in atomic percentage to provide a dark resistivity far lower than that of an undoped crystal, and a high dark resistance layer, which is of the same crystal structure as that of the single-crystal plate and lattice-matched therewith and has photoconductivity, electro-optic effect and a high dark resistivity, is provided on the light incident side of the single-crystal plate. A tapered low dark resistance single-crystal plate may be used which is formed of Bi.sub.12 MO.sub.20 (where M=Si, Ge, or Ti) or similar sillenite type crystal, doped with phosphorus (P) in the range of 0.03.ltoreq.P.ltoreq.0.

Abstract: A method is disclosed for manufacturing a bismuth-containing oxide single crystal, in which vapor of bismuth or alkylated bismuth and vapor of an organic compound of other metal ion components of a crystal are introduced into a heated reaction chamber to be reacted with oxygen gas, so that the desired bismuth-containing oxide single crystal is deposited on a substrate prepared in the reaction chamber. A Bi.sub.12 SiO.sub.20 single oxide crystal can be produced by the use of bismuth or alkylated bismuth and alkylated silicon or silicon alkoxide or by the use of bismuth or alkylated bismuth and alkylated germanium or germanium alkoxide. A (Y.sub.1--x Bi.sub.x).sub.3 Fe.sub.5 O.sub.12 single crystal can be poduced by the use of bismuth or alkylated bismuth yttrium alkoxide and carbonyl iron.

Abstract: A magneto-optical recording medium comprising: a recording layer of a magnetic thin film low in the Curie temperature or magnetic compensation temperature and high in coersive force and having an easy axis of magnetization in a direction perpendicular to the film surface; a reproducing layer disposed adjacent the recording layer and large in the magnetic Kerr rotation angle and having an easy axis of magnetization in a direction perpendicular to the film surface; and a transparent substrate disposed on the side of incidence of light. In accordance with the present invention, a reflecting metal layer is provided for reflecting light having entered from the side of the transparent substrate and passed through the recording layer and the reproducing layer. A dielectric layer may be further disposed at least on one side of the transparent substrate or the reflecting metal layer with respect to the recording layer and the reproducing layer.

Abstract: A magneto-optical recording medium having an easy axis of magnetization in a direction perpendicular to the film surface, characterized in that a readout medium layer, a reflection layer and a recording medium layer are sequentially disposed in a direction of the incidence of a reading-out light, thereby to increase a reproduced output.