Bandwidth Reduction of Stimulated Brillouin Scattering and Applications in Optical Communication - Stefan Preussler - Bog

Stimulated Brillouin scattering is the most dominant nonlinear effect in single mode optical fibers. Its unique spectral characteristics, especially the narrow bandwidth of 20 - 30 MHz enable numerous applications, including optical spectrum analysis, delay and storage of light, distributed sensing and optical signal processing. Most of them would benefit from a reduction of the Brillouin gain bandwidth.This dissertation demonstrates several methods for significant reduction of the Brillouin gain bandwidth, including a multi-stage system, the superposition of the gain with two losses as well as the utilization of a frequency domain aperture. Thereby the Brillouin gain bandwidth can be reduced significantly down to 3 MHz, which equals 15% of the normal bandwidth.Furthermore, the reduced Brillouin gain bandwidth is employed for various applications. First, the resolution and the dynamic range of a Brillouin based optical spectrum analyzer are enhanced significantly. Second, a new technique for the storage of optical data packets, called Quasi-Light-Storage, is introduced and the maximum storage time is increased to 160 ns for 8 bit data packets. Finally, Brillouin scattering is used for the processing of optical frequency combs, leading to the generation high quality of mm- and THz-waves, as well as almost ideal sinc-shaped Nyquist pulse sequences.