PASSIVE LIGHT NETWORK WITH AMPLIFIED LED TRANSMITTER

PROBLEM TO BE SOLVED: To overcome an optical beat interference problem by a light source provided with sufficiently strong power and wide spectra by providing the passive optical network with a light transmitter connected to a light distribution system and including an amplified light-emitting diode(LED) and a light receiver which is photocoupled with the light distribution system. SOLUTION: Light from a laser 70 is passed through a variable light attenuator 73, before being coupled with coherent optical signals outputted from a laser 71 and an amplifier LED 72. The attenuator 73 is used for the relative intensity control of signals and interference channels. The coupled optical signal is passed through a variable attenuator 74 before arriving at the light receiver 75. The electric signal obtained is an amplified downstream of the receiver 75 and filtered by a filter 76 to select a signal channel. At this time, the signal is demodulated by an FM discriminator 77. Since low-pass filters 78 to 90 are used for the array, nearby channel interference can be avoided, and the transmission RF bandwidth of each channel is limited. Thus wide channel space of 12 MHz can be used.