【作者】 吴燕；

【导师】 詹黎；

【作者基本信息】 上海交通大学 ， 光学， 2012， 硕士

【摘要】 光纤中可控快慢光技术研究具有十分重要的意义。因为快光和慢光极有可能运用于发展快速存储器及光学控制延迟线这两个方面，这对实现全光通信有着重要的实用价值。在过往的研究中，控制脉冲展宽也会限制其延迟时间，因此人们花了大量的经历在这方面的研究。本文主要研究了如何控制脉冲宽度同时又能保有一定可观的延迟时间。我们已经知道，脉冲的展宽主要由两个因素所影响，增益展宽和色散展宽。我们主要通过利用慢光过程中的脉冲展宽和快光过程中的脉冲压缩相互抵消，来获得一个经过光纤传输零色散展宽的脉冲。我们从理论上做了这样的分析，由于在布里渊散射产生的快光是发生在反常色散区，而慢光是发生在正常色散区，对于这两者的GVD参量的符号是相反的，由此引发思考，通过两者相抵，来获得一个脉冲在经历减慢过程时宽度放大，而经历加快时宽度缩小来得到一个色散展宽为零的脉冲。当然这里一定要提到的是，单是无啁啾的脉冲是实现不了的，只有带有啁啾的脉冲才有可能在一定的条件下发生脉冲宽度的缩小。同时，我们进一步通过理论数据上的分析，布里渊散射产生快光是通过布里渊衰减得到的，产生慢光是布里渊增益得到的，在这两个过程中，其脉冲宽度的变化也是相反的，在这样的条件下，我们同样将因布里渊增益所产生的脉冲展宽部分压缩，虽然并没有得到一个零增益展宽的脉冲，但相比起单泵浦系统而言已经有很大的提升了。同时我们考虑到三阶色散的影响等其他非线性效应的影响，考虑用均方根宽度（RMs）来描述脉冲的宽度，这是一个较为理想的改进。相比其他方法，我们的理论可以用于各种慢光系统同时可以运用于10Gb/s和2．5Gb/s的通信系统。本文的另一个主要内容是受激布里渊散射产生快光的过程和实验操作。鉴于快光的产生是由于布里渊损益，所以快光在传输过程中往往被吸收了，而无法较长距离的传输，在这一点上我们也加以研究。通过光纤环可以加大其脉冲的加快时间避免损耗。更多还原

【Abstract】 The study of controllable pulse delaying and advancement in an optical fiber is very necessary because it can be potentially used for the development of fast-access memories and optically-controlled delay lines which plays an important role in the realization of all-optical communication system. Now the main problems are to increase the pulse delay and reduce the pulse width.Usually, the broadening of a pulse is due to two factors: SBS gain broadening and dispersion broadening which includes GVD and TOD, and thus it is impossible to get a zero-broadening pulse for an original un-chirped pulse in a linear slow-light system. We show in theory that the two GVD parameters in the normal and anomalous dispersion regions can be modulated to counteract so that we can get a zero-GVD-broadening pulse by using two broadband pumps with different powers and spectral widths. Using the method of dispersion compensation, the third-order dispersion (TOD) effect can also be canceled out simultaneously.Besides, the pulse compression occurs in the anomalous dispersion region also. The gain broadening in the first slow-light stage can also be compressed in the second stage. Thus we can get a nearly zero-broadening pulse, which remains the time delay. We calculate the root-mean-square (RMS) width of the pulse in our paper to avoid some ignorance of the sub-pulses.We also studied SBS fast light and its experimental setup. We know, owing to the effect of gain saturation, the fast light experience strong loss and cannot have long distance propagation. Here we make SBS fast light propagate in the fiber ring cavity in order to get an advanced pulse.Through the theory we shown and the experimental setup of SBS slow light and fast light, it is possible to get a delay pulse with low distortion. We believe the method will be useful for further study. Our process is linear and it can be replaced by almost all the achieved method for slow-light system and different pump beam spectrum.更多还原