A hybrid analogue/digital optical fiber transmission system using pulse width and amplitude modulation

We present the principle and design of a cost-effective optical fiber communication system to support hybrid digital and analogue signal transmissions, by simultaneously using pulse width modulation (PWM) for the analogue signal and 2-level pulse amplitude modulation for the digital signal. A transmission system using the proposed pulse width and amplitude modulation (PWAM) essentially requires the same channel bandwidth as a conventional analogue PWM system. Moreover, we analyze the performance of PWAM optical fiber systems by considering the signal-to-noise ratio of 50 dB for video communications and the bit error rate of 10/sup -9/ for digital communications.