No abstract

No abstract

An optical 32QAM-OFDM-PON system with different numbers of sub-carriers using discrete multitone (DMT) modulation and demodulation is designed and demonstrated by experiment. Electron-optic generation, directly photoelectric detection, and electrical self-mixing reception of 32QAM-OFDM downstream signals are achieved. 5Gb/s 32QAM-OFDM downlink signals with different numbers of sub-carriers are successfully transmitted over 42 km SMF-28. Peak-to average power ratio (PAPR) characteristic, computational complexity and bit error rate (BER) performance are analyzed. The results show that the sub-carriers numbers of 32QAM-OFDM downlink signals should be carefully selected according to the actual requirements, if spectral efficiency, PAPR characteristic, computational complexity and receiver sensitivity are considered.

Abstract. In this letter, a novel scheme which can realize high-speed optical signals transmission and reception by using 4-pulsed amplitude (4-PAM) modulation and demodulation in 10 Gb/s free-space optical (FSO) systems. In this scheme, one PAM sequence generator module, one M-element pulse generator (MPG) module and one Mach-Zehnder Modulator are used to generate 10Gb/s 4-PAM optical signals. And then, the generated optical signal is transmitted in free space. Finally, it is directly detected and demodulated (IM/DD). We measure time-domain sequential waveform curves, optical spectrum curves, eye diagrams, and analyze the reception performance of 10Gb/s 4-PAM signals before and after transmission.

Reliability is one of the key issues in widely application of real-time video transmission. The fault-tolerant mechanisms of 1394b optical bus protocol are investigated for 1394b optical bus-based real-time video. In addition, a method of hardware redundancy fault-tolerant is proposed. The hardware topology is built with embedded video function nodes, and fault-tolerant control software is realized on VC platform. Furthermore, the 1394b optical bus-based video transmission is demonstrated by experiment, due to which, performances of fault-tolerant for the transmission is evaluated.