Bidirectional transmission of analog/digital data and video signal via optical fiber for use in reliability test

This paper describes a simple version of the full duplex optical fiber transmission system and its application to vibration measurement. An optical circuit configuration of this transmission system is simplified using a laser diode package with a built-in photodiode for monitoring the laser output power. This transmission system can simultaneously transmit digital data of up to 9600 bps in one direction, and analog data of DC to 100 kHz and an NTSC color video signal in the opposite direction through an optical fiber. This transmission system was applied for vibration measurement. While digital control data was transmitted from the monitoring room to the testing room, analog vibration data and a video signal were transmitted from the testing room to the monitoring room through the transmission system. Digital control data was used to determine the sensing position for the vibration sensor. Analog vibration data was obtained from the vibration sensor. A video signal was used to specify the measuring point. Vibration of components was three-dimensionally read from the vibration sensor.