Tunable all-optical delay structure based on stimulated Brillouin scattering slow light

An tunable all-optical delay structure using stimulated Brillouin scattering slow light process is proposed. The structure uses stimulated second-order Stokes wave as signal and stimulated first-order Stokes wave as pumping to reduce coupling mismatch of frequency and phase in gain amplifying process and simplify the structure complexity. The delay time between signal demodulated from amplified second-order and RF signal can be easily tuned by adjusting the variable optical attenuator in the system. The delay can be tuned from 13.8 ns to 22.2 ns at a power gain of 8 dB when RF frequency is set to 50 MHz.