Study On Typical Applications Of Stimulated Brillouin Scattering In Optical Fibers

Slow light technology can greatly improve the performance of the communication, radar, measuring and testing systems as well as provide an access to get a deeper understanding of the interaction essence between light and matter for human. Therefore, the research on slow light technology is of considerable theoretical significance and practical value. Slow light based on stimulated Brillouin scattering has already been one of the hottest topics recently in slow light delay technology field owing to its advantages such as compatibility with fiber systems, flexibility of wavelength, controllability of delay and room-temperature operation.Two methods are used to realize slow light based on stimulated Brillouin scattering. The first one to slow down the propagation velocity of optical pulses is using larger group refractive index within Brillouin gain spectrum, which has its limitation because the gain spectrum bandwidth is limited as well as the effect of high-order dispersion. So it is usually difficult to obtain a large time delay, and also results in a large distortion. The other method is the optical buffer based on acoustic storage, where in a large delay-bandwidth product can be obtained. But the storage time is limited by the phonon lifetime and a higher peak power of control pulse is require. The topics of how to reduce signal distortion and to enhance delay-bandwidth product are investigated in this dissertation, in these two methods of slow light technology based on stimulated Brillouin scattering. The main contents of the dissertation are as follows:1. The influence of parameters such as the shape of pump light, pump power, the effective mode area, Brillouin gain coefficient and gain bandwidth on time delay and pulse broadening are comprehensively analyzed. The following conclusions are obtained:Firstly, larger pump power and effective mode area make the Stokes pulse reach larger time delay and pulse broadening while smaller gain coefficient and gain bandwidth can make the same results under the condition of small signal. Secondly, the time delay and pulse broadening decrease faster with the gain increasing if larger pump power, gain coefficient and gain bandwidth as well as smaller effective mode area are provided after gain saturation. Finally, the continuous pump light with the slowly rising edge can increase the fractional delay to0.433for a120ns long Gaussian-shaped stokes against3.20for a20ns short Gaussian-shaped stokes pulse. In addition, it also reduce the pulse broadening for long Gaussian-shaped stokes pulse.2. For the slow light technology based on acoustic storage. Firstly, the relationship between the control pulse and the performance characteristics such as pulse distortion, readout efficiency and output SNR with Gaussian and rectangular pulse as data pulse has been discussed. Then, the influence of the edge sharpness of injected Super-Gaussian pulse as well as the chirp parameter of control pulse on pulse width and readout efficiency of retrieved data pulse are investigated. Finally, storage effects of super-Gaussian pulse in the As2Se3fiber are analyzed. The following conclusions are obtained:Compared with Gaussian pulse with the same width, rectangular control pulse can improve readout efficiency and output SNR of retrieved data pulse and compress its pulse width for its wider spectrum. The width of retrieved data pulse is compressed when the order of super-Gaussian pulse is no less than2. The width of retrieved data pulse becomes narrower with the increasing order. Larger chirp parameter and power of control pulse can compress the width and improve the readout efficiency of retrieved data pulse. Zero-broadening of Super-Gaussian pulse with different edge sharpness can be obtained by optimizing the chirp parameter of control pulse. And, storage media with longer phonon lifetime, larger coupling coefficient and Brillouin gain coefficient can improve the storage performance.