Basic Concept

Within this project, a data transmission segment will be set-up with a total fibre length of 5 km and the transmission of video and audio signals are studied. The project starts with the connection of the fibres to the transmitter and receiver. In the next step, the electronic connections are done. The set-up can operate with a colour CCD video camera, a CD-player as an audio source, a TV screen as a monitor as well as serial RS232 data devices. This project demonstrates in an impressive way the new exiting telecommunication via optical glass fibre.

Experimental Set-up

The set-up consists of the base unit housing which provides all further slot-in modules with the required electrical power. The data transmission line consists of 5 segments of optical single mode fibres each having a length of 1 km. The electronic signal (video, audio or data) are fed into the optical transmitter where the conversion to laser light takes place. The optical output of the transmitter with a wavelength of 1.3 µm is connected via a fibre patch cable to the desired glass fibre segment. Depending on the goal of the investigation, the 5 fibre segments can be inter-connected also via fibre patch cables. A maximum distance of 5 km is achieved when all segments are connected in series which each other. The end of the fibre line is either patched to the provided InGaAs fibre coupled photodetector (PD) in order to measure or monitor the optical signal or it is connected to the optical receiver. The back conversion to electronic signals takes place there and the individual video, data or audio signal can be connected to a monitor, computer or audio system.
Due to the fact that a combination of 5 different lengths of the fibre line is available, reliable measurements of the attenuation can be carried out. For this purpose, the use of the frequency generator is recommended for a steady signal.