Optical multiplex communication system

In an optical multiplex communication system for transmitting n kinds of digital signals from a transmitting end to a receiving end by the use of a single digital-link optical fiber line, the improvement wherein:

• said transmitting end includes means for generating said digital signals so that only one of said digital signals goes true at a time, and two or more digital signals never go true simultaneously;
• clock pulse generating means for generating n kinds of carrier clock signals having different pulse frequencies, one for each of said digital signals of said digital signals and a respective one of said carrier clock signals when said digital signal goes true, to produce a logical product output, whereby said logical circuit means produces n logical product outputs;
• means for producing a logical sum output of said n logical product outputs;
• and digital optical transmitter means for converting the logical sum output of said logical circuit means to a light signal and delivering the same onto said optical fiber line;
• and
• said receiving end includes digital light receiver means for receiving said light signal from said optical fiber line and converting the same to an electric signal output;
• n band-pass filter means each having a pulse frequency pass band corresponding to the frequency of a respective one of the pulse frequencies of said carrier clock signals, so as to extract from the electric signal output of said digital light receiver means a signal having said one pulse frequency and passing said extracted signal;
• and detection circuit means for detecting the extracted signal passed by each of said filter means and generating signals corresponding to respective ones of said digital signals, thereby restoring corresponding ones of said digital signals.