Bandwidth reduction of stimulated Brillouin scattering and applications in optical communication

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.