Polarization-assisted stimulated Brillouin scattering-based optical signal processing
Abstract: Microwave photonics (MWP) processing provides numerous advantages over electrical domain techniques, such as broad bandwidth, long reach and immunity against electro-magnetic interference. An important application of MWP is the transmission of RF signals over long distances using optical fibers, or radio-over-fiber (RoF). Many RoF systems are based on the multiplexing of densely packed subcarrier tones. The monitoring of such transmission requires optical spectrum analyzers (OSAs) with high resolution, on the order of MHz. The required resolution is two orders of magnitude higher than that of standard equipment. In this work, I demonstrate and employ an OSA with 10 MHz resolution, that is based on the nonlinear optical propagation phenomenon of stimulated Brillouin scattering (SBS) amplification in standard optical fibers. The vector attributes of SBS amplification considerably improve the dynamic range of the spectral measurements.
Many RoF applications also involve RF filtering. Many implementations of MWP filters were proposed in the literature, however the realization of sharp, tunable MWP filters remains challenging. Herein I present a significant enhancement of MWP filters that are based on the polarization attributes of SBS. The method is employed in the realization of sharp, highly-flexible MWP bandpass filters with a single passband, and tunable central transmission frequency, bandwidth and shape. The proposed selective filtering and analysis can be very instrumental in all-optical signal processing in MWP systems.
* The research presented in the seminar was carried out towards the M.Sc. degree, with the supervision of Dr. Avi Zadok