Photonic Generation of Microwave Frequency Shift Keying Signal Using a Polarization Maintaining FBG

A photonic generation of microwave frequency shift keying signal (FSK) with large frequency tunability is proposed and experimentally demonstrated. A polarization modulator combined with a polarization maintaining fiber Bragg grating is used to transform a carrier-suppressed double sideband signal to a wavelength-shift-keying one, which is subsequently mixed with a tunable optical source to achieve frequency modulation. A proof-of-concept experiment is demonstrated to obtain an FSK signal at 9.5/12.5 GHz. The carrier frequency has been tuned from 7.2 to 14.8 GHz by adjusting the laser wavelength. Moreover, a radio over fiber transmission link is established to investigate the transmission performance of the generated FSK signal. The bit-error-rate curve of the received FSK signal at 9.5/12.5 GHz for a 5-km single mode fiber and 2-m wireless transmission is presented.