Research On The Optical Orthogonal Frequency-division Multiplexing Technique-based Video Transmission Systems

Orthogonal frequency division multiplexing(OFDM)is a special class of MCM system.OFDM has triumphed in a broad range of applications in the RF domain(802.11 a,et al)and traditional wired network system(ADSL,et al).OFDM modulation and demodulation techniques greatly improve the system spectrum efficiency which makes it shine in band-limited system.Optical OFDM technique can combat chromatic dispersion and first-order polarization mode dispersion(PMD)thus is suitable for long-haul transmission without compensation in optical domain.Passive optical network(PON)based on optical OFDM technique supports flexible dynamic bandwidth allocation and smaller bandwidth granularity for future optical access network.In this paper,we begin with a quick look back at the history of OFDM and provide a comprehensive view of the existing research in Optical OFDM technique.The drawbacks of current optical OFDM implementation based on off-line processing is presented and we further stress the importance of real-time optical OFDM system based on hardware platform.According to the principle of optical OFDM,we divided our work into three parts:Firstly,a digital base-band OFDM transmitter based on field programmable gate array(FPGA)and high-speed digital-to-analog converter(DAC)is developed and verified.Secondly,a digital base-band OFDM transmitter based on field programmable gate array(FPGA)and high-speed analog-to-digital converter(DAC)is developed to correctly recover the 1.485 Gb/s 720 p high-resolution video signal,we also verified its performance.Finally,we built an optical fiber transmission platform based on OFDM transceiver to successfully transmit 1.485 Gb/s high-resolution video signal in 20 km standard signal mode fiber(SSMF)without optical amplifier.Ex perimental results show that the receiver performs error-free recovery of original video signal after fiber transmission even without Forward Error Correction(FEC)technique which further verified the performance of optical OFDM technique.