EventBilgehan Paray

Development of Fiber Optical Delay Line Based 10 Ghz Phase Noise Measurement System

Microwave  photonics  is  an  emerging  field  of  study  exploiting broadband,  low loss photonics technology for high spectral purity microwave  generation,  pro-cessing and distribution.  Fiber optical delay lines are such systems employed successfully for generation and phase

noise analysis of microwave signals highspectral  purity.   Low  loss  and  wide  bandwidth  of  the  fiber  optical  delay  line permits  much larger  delays  to  be  realized  at  a  reasonable  loss  at  microwave frequencies.  In this study, fiber optical delay line based frequency discriminator phase noise measurement system is designed and implemented to resolve ultra low phase noise spectra of optoelectronic oscillators.  System design is described in  detail  including  fiber  optical  and microwave  component  characterizations,selection  criteria,  system stabilization  against  environmental  fluctuations  and system calibration.  Phase noise measurements for various RF synthesizers available in the laboratory are conducted with the developed system and compared to spectrum analyzer phase noise measurements to validate system calibration.Finally, phase noise spectra of optoelectronic oscillators(OEO) with 1 km and 2 km delay elements are demonstrated with the developed system.  With 2 km OEO, system can resolve phase noise spectra as low as -141 dBc/Hz at 10 kHz offset from 10 GHz carrier frequency.