International audienc

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A high-repetition-rate optical pulse generator which employs a Fabry-Perot electro-optic modulator as the output coupler of a laser resonator was constructed. Using this generator with a He–Ne 6328-Å laser tube, 21-psec optical pulses at a repetition rate of 2.7 × 109 pps were experimentally obtained with an average power level of 0.5 mW. In addition, it is demonstrated that the width of the pulses obtained from this generator can be narrowed without regard to the gain-linewidth limitation. This kind of pulse generator may be particularly useful for obtaining short optical pulses from low-gain gas lasers, and it is possible to obtain 1010-pps picosecond pulses from a He–Ne 6328-Å laser.

A novel integrated optic pressure sensor was constructed with the Mach-Zehnder interferometer structure of glass waveguides on a silicon substrate. Pressure is sensed by detecting the deformation of a thin diaphragm fabricated by using the anisotropic etching of a silicon substrate. The basic design concept of the present sensor was provided by analyzing its operation. The measurable pressure range and the sensitivity can be set by the proper selection of the diaphragm structure. A device was built and its operation performances were tested at 633 nm. For the fabricated device, the measured halfwave pressure was 0.8 x 10(5) Pa and the extinction ratio was 10 dB.

characterization of transfer efficiency in charge-coupled devices,"Abstract-A traveling-wave electrooptic phase modulator using a Tiin-diffused LiNb03 optical waveguide was designed and constructed with emphasis placed on broad-band operation. As a microwave waveguide, a coplanar parallel stripline of aluminum with characteristic impedance of 48 was fabricated on the crystal surface. The electrodes are 1.5 pm thick, 1 cm long, and 60 pm apart. The modulator was tested at 0.63 pm over a bandwidth of 75 GHz. For 250-mW drive power, the measured phase-modulation index was 1 rad up to about 3 GHz and reduced to 0.5 rad at 7.5 GHz. S