聚合物光纤中的模式耦合及其对带宽的提高

光在聚合物光纤(POF)中传输时存在较强的模式耦合,由于模式耦合的影响,聚合物光纤的传输带宽得以提高。根据能流方程对阶跃型聚合物光纤光传输中的模式耦合进行了研究,从实验上测量了聚合物光纤的模式耦合系数,测量得到的模式耦合系数为7.61×10-4rad2/m。用测得的模式耦合系数对聚合物光纤中的模式耦合进行数值模拟,得到聚合物光纤的模式耦合长度约为20 m。由模式耦合长度可以得到聚合物光纤的真正带宽,其在150 m传输距离的带宽约为130 Mbit/s。为了验证这一结论,进行了125 Mbit/s.150 m的局域网(LAN)通信实验,通过对发射、接收波形及通信眼图的分析表明,由于模式耦合提高了聚合物光纤的传输带宽,使其可以在150 m的距离上进行百兆速率的通信传输。

Mode Coupling in Polymer Optical Fiber and Its Enhancement to Transmission Bandwidth

There existed strong mode coupling when light traveling in the polymer optical fiber (POF). Due to the mode coupling , the transmission bandwidth of POF was enhanced. The mode coupling of POF was studied based on the power-flow equation. The mode coupling coefficient of POF was measured experimentally, the measured coupling coefficient was 7.61×10-4 rad2/m. The mode coupling process in POF was simulated numerically using measured coupling coefficient; a coupling length of 20 m was obtained. The real bandwidth of POF was revealed from the coupling length. The transmission bandwidth of POF was about 130 Mbit/s over 150 m. To testify the result, a 125 Mbit/s·150 m local area network (LAN) POF communication experiment was carried out, the transmission waveform and communication eye diagram were analyzed. The experiment results showed that the transmission bandwidth of POF was enhanced by mode coupling, the transmission distance of POF could reach 150 m at data rate 125 Mbit/s.