Optical fiber multifrequency SWFM transmission system for sending low-speed parallel data

Presented is a new type of optical fiber parallel data transmission system utilizing the multifrequency parallel signals. The multifrequency parallel signals are used to modulate the squarewave carrier by squarewave frequency modulation (SWFM) scheme, and then transmitted through a single optical fiber. The system can send 8-bit parallel data with a low speed of 5 kbps, but in a long distance of 2 km through a multi-mode optical fiber. In addition, because of the excellent stability against EMI, the proposed system can be used in inferior environment to transmit the statuses or the manual control signals between sensors and monitors in both directions for various industrial uses.<<ETX>>