This paper clarifies received level characteristics of wide band transmission such as a TV channel by computer simulation. The results are as follows: i) Received level in wide band is not a deep depth, and has a no-Raylegh distribution. ii) Received level depth decreases with increasing number of arriving waves. iii) Envelope autocorrelation is almost independent of receiving band width. Therefore, using Yagi-receiving-antenna, a high received level can be detected by moving the antenna in a few wavelengths. iv) Frequency-envelope correlation is higher in the receiving wide band. In a TV channel with a 6MHz adjacent channel, however, the adjacent channel is not guaranteed a high level even if the present receiving level is high because of the large 6MHz separation.

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LiNbO3 optical switch is certain to play a major role in guided wave systems. Here, we present the improvement of device performance by introducing the MgO/Ti diffusion. The problem of the conventional Ti diffused waveguide and the effect of MgO diffusion are discussed. Characteristics of 1×8 optical switch is reported.

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A strictly non-block matrix switch is a basic component in photonic space-division switching system and broadcast diaital signal switching system. For practical use of these systems. polarization independency for such switches is very important. This letter reports the structure and characteristics of polarization independent LiNbO_3 matrix switches.

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The laser diodes and modules have been developed for CATV systems. The low distortion characteristics of the laser diodes was acquired by the optimization of the coupling constant. The modules using the improved LD are possessed of low distortion, low noise and flat frequency characteristics required for the system and also high reliability.

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Described is a new optical wavelength division multiplexed system for trans mitting squarewave frequency-modulated audio, video, and data signals operating at wavelengths of 850 nm and 1300 nm. The distortion of the demodulated audio signal was 0.6% at 1 kHz with an SNR of 70 dB, and the freoquency response was flat with a variation of less than 3 dB over the frequency range from 30 Hz to 20 kHz. The DP and DG of the video output signal were 2 degrees and 3% with an SNR of 60 dB, respectively. For the telephone voice signal, the frequency response was flat over the frequencies of 0.3 kHz to 3.6 kHz, where the SNR was 59 dB. This system can also transmit data at a speed of 64 kbits/s, and it can transmit the high-quality TV program and audio signal simultaneously to a remote location at a distance of 2 km when the transmitter output optical power is -19 dBm and the receiver sensitivity is -23 dBm.

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