【作者】 夏长超；

【导师】 李淳飞；

【作者基本信息】 哈尔滨工业大学 ， 光学， 2007， 硕士

【摘要】 随着光纤通信网络的迅速发展,在现有的光网络中,光信号的交换所用的仍然是电子的交换器,电子开关器件制约了光纤通信系统对信息数据处理速率的进一步提高,严重阻碍了光网络的发展,成为所谓“电子瓶颈”。解决“电子瓶颈”的有效途径是采用全光开关在光域上实现传输和交换。全光开关具有高速、大容量、高可靠性和无需光电转换等优点,对宽带多媒体通信的实现和降低成本都具有重大意义。由两个光纤耦合器制成的环型谐振腔全光开关具有结构简单易于集成、容易与光纤传输网耦合、插入损耗小等优点。加上它在其它应用方面的巨大潜力,目前已成为光开关研究的热点。本文主要研究含有掺铒光纤放大器的光纤环共振腔全光开关,详细分析了这种全光开关的原理。利用光纤弱耦合模理论,分析了掺铒光纤放大器的作用。在理论上先后计算和分析了无损耗和有损耗情况下环腔的开关特性。有损耗时很难实现全光开关。当我们在环腔中加入掺铒光纤放大器后不仅会大幅降低开关功率,还能够提高开关的比率,但开关时间也随着增加了。我们可以通过控制放大器的增益和耦合器的反射率等参数,来适当增加开关功率,或减小开关时间。开关阈值功率可以低达几毫瓦,开关时间可短至几百纳秒。在此理论研究的基础上,我们进行了实验研究,对理论进行验证。将实验中实测的环共振腔参数代入理论公式计算,得到的开关阈值功率可达百微瓦量级。最后,介绍了一种可行性更强的开关实验方案,当环腔处于非谐振状态下,通过调制掺铒光纤放大器的泵浦光功率来实现全光开关,可以得到百分之七十左右的开关现象。我们还实验研究并讨论了耦合器的分光比、入射光功率等因素对开关特性的影响。更多还原

【Abstract】 With the rapid development of the network of optical fiber communication, In the present optical network, the switching between optical signals still use the electronic devices, which has a slow speed. It restricts the further enhancement of data processing speed and extremely blocks the development of optical network. It is so called "electronics bottleneck". Using all-optical switches in optical network is an effective way to solve the problem of "electronics bottleneck". All-optical switches have many advantages: high speed, huge capacity, high reliability and without O-E-O conversion. All-optical switches can be used in broadband multimedia communication, and for reducing the cost of network.The structure of the double fiber coupler ring resonator all-optical switch is simple, it can be integrated easily; it can also be easily coupled with fiber network, and the insertion loss of it is quite small. Owing to the great potential of the double fiber coupler ring resonator all-optical switch, it becomes one of the hot research subjects.In this thesis, we mainly study on the double fiber coupler ring resonator all-optical switch containing an EDFA, and analyze this kind optical switch principle in details. By using the fiber weak coupled-mode theory, we also analyze what a role the EDFA plays. We calculated and analyzed the switching properties of the ring switches in the cases without loss and with loss. We find that it is hard to realize the switching in the device with loss in the ring. When we insert an EDFA in the ring, the switching power can be reduced rapidly and the switching rate can be increased, however, the switching time will be increased at the same time. By controlling the gain of the EDFA, the reflectivity of couplers or other parameters, we can make a tradeoff between the switching power and the switching time to obtain the desired switching parameters. For example, we can obtain the switching power down to several mW, the switching time can be controlled below several hundred ns.Based on the theoretical works, we made the experiments for proving the theory. When inserting the experimental data into the theoretical formula to calculate the switching power, we can get the switching power is several hundred μW only.Finally, we introduce a feasible experiment. The switching can be realized by controlling the pump power of the EDFA, while the ring is not at the resonance. We can obtain the switching rate about seventy percentage. We also discussed that the influence of the output power ratio of the fiber coupler and the input power etc. to the switching properties.更多还原