Chihiro Masuda

Laser diode interferometer for vibration and sound pressure measurements

A laser-diode interferometer for vibration measurement was constructed using two acoustooptical tunable filters (AOTFS) with slightly different frequencies of the diffracted light. A sound pressure measurement of a condenser microphone using a combination of a polarization-maintaining fiber and the laser-diode interferometer was demonstrated. The advantages of this interferometer are the ability to use various laser beams in the 0.4-1.2- mu m wavelength region by varying only the acoustic frequency of the OTF, and the ability to use remote measuring equipment for the sound pressure by using a polarization-maintaining fiber. >

Optical two-way TV transmission.

We performed a basic experiment on the optical transmission of two-way TV signals, utilizing a single optical fiber and two sources of light of the same wavelength. In our experiment, crosstalk caused by optical reflection at the fiber end face was canceled by electrical forward feed. The advantage of this method is that the wavelength of the light source can be selected arbitrarily without the help of an interference filter. In addition, the crosstalk can be canceled by a simple electronic circuit.

An application for optical measurements using a rotating linearly polarized light source

The apparatus of a linearly polarized light source that rotates at arbitrary high frequencies was constructed using an acoustooptic tunable filter employing a TeO2 crystal. The characteristics of optical devices, such as birefringence of optical fiber, transmissivity of half mirror, angle of rotation of optical isolator, and film thickness and refractive index of optical thin-film, were measured using this apparatus. The advantages of this apparatus are its simple construction, ability to produce high rotating frequencies, and ability to use various laser beams.

A 3-D display using a laser and moving screens

A method of displaying 3-D images using a laser is reported. A real 3-D image in space was constructed by projecting the cross-sectional images of an object on moving screens employing a laser. This method may be applied to display computer graphics or CT images.A method of displaying 3-D images using a laser is reported. A real 3-D image in space was constructed by projecting the cross-sectional images of an object on moving screens employing a laser. This method may be applied to display computer graphics or CT images.

A New Automatic Measuring Method for Optical Fibers Using an Acoustooptic Tunable Filter

This paper describes a newly developed technique for measuring various optical fibers as a function of wavelength, utilizing a combination of an Acoustooptic Tunable Filter (AOTF) employing TeO2 crystal and various incoherent light sources. Using these apparatus, loss, dispersion, and polarization properties in optical fiber can be measured very easily by varying the wavelength electronically and at high speed.

Monochromatic Light Source with Variable Wavelength using an Acoustooptic Tunable Filter and Its Applications for Spectrometry

ABSTRACT The construction of a light source with variable wavelength utilizing a combination of an Acoustooptic tunable filter employing a Te02 crystal and an incoherent white light source, of which the wavelength and intensity of the optical output is to be arbitrarily controlled, are described. As example of applications, an automatic measuring method for spectrometory are proposed. As a result, the following conclusions are obtained. (1) The optical output power of the apparatus depends on the wavelength characteristics of the feedback system. (2) The spectral reflectance characteristics can be measured automatically by using the combination of a light source with variable wavelength and a microcomputer . ( 3) The measurement time of the spectral reflectance characteristics is about 10 minutes . ( 4) The spectral sensitivity and the spectral transmittance characteristics were expressed on an oscilloscope as still picture of the periodic time T=40ms.

Radiation Characteristics of The Major Angle Corner Reflctor Antenna with a Inclined· Feeded Dipole

優角コーナーレフレクターアンテナのダイポール素子を傾けた場合の諸特性について, 理論と実験の両面から比較検討した.このアンテナは, ダイポール素子の傾むき角, 開口角を適当に調整することにより, 正面方向で任意偏波が得られることおよび, その指向性は扇形の特性を示し, 垂直, 水平の両偏波が受信可能であること等が特徴である.