Laser audio transmission experiment

A wireless laser audio transmission system is designed.In the emission part,the 90 MHz carrier wave is modulated by frequency,then the intensity of the output light of a semiconductor laser is modulated.In the receiving part,optical signal is changed into electrical signal by optical-to-electrical transducer,then the electrical signal is demodulated to the original signal.The system's amplitude-frequency characteristics,dynamic characteristics and delay characteristics are measured.The experimental results indicate that the system can resist interference and receive very weak single signal using twice modulation method.