提出了一个完整的高灵敏度光正交频分复用(OOFDM)系统,以实现高速长距离传输。实验中,将10Gbit/s的4QAM调制OOFDM信号在光纤中传输了50km,直接探测后得到的星座图和误码率都达到了良好的效果。在此基础上,对比了采用雪崩二极管(APD)和传统的光电二极管(PIN)两种不同的探测方式,结果发现,使用APD探测使得OOFDM系统接收的灵敏度提升了5.2dB。
A complete optical orthogonal frequency division multiplexing(OOFDM) system is presented in this paper,which is employed to achieve long distance transmission with high efficiency.The OOFDM signal in 4-quadrature amplitude modulation(QAM) with the code rate of 10 Gb/s is transmitted 50 km in the fiber,and the constellation diagram and error rate obtained through direct detection show good performance.Two detection fashions that use avalanche photodiode(APD) and traditional photodiode(PIN) respectively is compared.The results show that the sensitivity of the OOFDM system receiver using APD for detection is enhanced by 5.2 dB.