Abstract: A wavelength-selectable laser with a resonance region formed by two reflecting surfaces include a gain medium generating a laser beam, a first filter, and a second filter. The first filter has a first controllable transmission region and transmits a first predetermined wavelength region of the laser beam generated in the gain medium, the first predetermined wavelength region matching the first controllable transmission region. The second filter has a plurality of periodically arranged second transmission regions and transmits a second predetermined wavelength region of the laser beam transmitted by the first filter, the second predetermined wavelength region matching one of the second transmission regions.

Abstract: The present invention aims at providing a control method and a control apparatus for controlling the operation setting of an optical device with high accuracy, so as to reliably obtain characteristics according to a desired relationship to be set corresponding to a signal light, immediately after the control start.

Abstract: The present invention aims at providing a multi-wavelength light source for stably generating a plurality of oscillated lights of arbitrary wavelengths by a simplified constitution. To this end, the multi-wavelength light source of the present invention is provided with an acousto-optic tunable filter (AOTF) on an optical path of a resonator including an optical amplifier, so that the AOTF selects lights of plural wavelengths from input lights corresponding to multiple surface acoustic waves at different frequencies, respectively, and shifts the frequencies of the selected lights to output the frequency shifted lights to the optical path, thereby realizing the stable multi-wavelength oscillation of lights being propagated within the resonator.

Abstract: There is provided a composite material that retains mechanical strength at a given level and at the same time, has a good balance in terms of lightweight properties and resistance to oxidation and a process for production thereof. Achievement is brought about by a composite material that can be produced by impregnating a particular metal silicide into a C/C composite or a carbonaceous composite material utilizing the C/C composite as starting material.

Abstract: A video recording and playback device with a built-in video camera includes an outer case having the same profile as that of a tape cassette that can be inserted into an exiting stationary video tape recorder.

Abstract: In a method of forming a transparent conductive film, an arc discharge type plasma produced by arc discharging is generated in an atmosphere wherein the pressure of an atmospheric gas is 3.0 .times. 10.sup.-4 Torr or higher; the plasma is converged onto a vapor deposition material for forming a transparent conductive film to thereby evaporate the vapor deposition material, whereby said transparent conductive film is formed on a substrate located above said vapor deposition material.

Abstract: This invention relates to a radio wave angle of incidence measurement apparatus which is applicable to radar and other detection systems, and which utilizes an antenna array with radiator elements distributed at a spacing larger than one half of the propagation wavelength. A radio signal is received by an antenna array that exhibit at least two different values of d/.lambda. (where d is the inter-element spacing of the radiator elements, .lambda. the propagation wavelength), and the resultant inter-element phase differences, of which there are at least two sets, are digitally measured. A phase difference converter circuit receives the digital signals representing the inter-element phase differences and processes them and generates an output signal that varies monotonically as the incident angle of the radio signal incident on the antenna array varies.

Abstract: Beer is brewed by a process which comprises mixing a high-gravity liquor comprising a fermenting wort of an original gravity of 14 to 21 degrees of plato after the high kraeusen period and a low-gravity liquor comprising a fermenting wort or wort of an original gravity of 3 to 6 degrees of plato and subjecting the resulting mixture to fermentation thereby to obtain a beer of an original gravity of 6 to 9 degrees of plato.