The Use of an Optical Power Combiner for Multiplexing Multiple Television Sources in Single-Fiber Optical Systems

A theoretical analysis is made of the maximum allowable transmission loss for frequency division multiplexed optical transmission of TV signals using an optical power combiner and intensity modulated multiple light sources. A PIN photodiode detector is assumed and the performance of a configuration using multiple light sources and an optical power combiner is compared to the performance of an electronic power combiner with a single light source. The results show that the maximum allowable transmission loss for 10 TV channels is greater than 25 dB if the modulation factor is 0.8 and the power supplied to the power combiner is 3 mW per light source. Practical optical fiber transmission systems carrying 10 TV channels over distances greater than 5 km therefore appear possible in the not-too-distant future if optical fiber cable with a loss of 5 dB/km is used.