We demonstrate an all-optical reconfigurable logic gate based on dominant nonlinear polarization rotation accompanied with cross-gain modulation effect in a single semiconductor optical amplifier (SOA).Five logic functions,including NOT,OR,NOR,AND,and NAND,are realized using 10-Gb/s on-off keying signals with flexible wavelength tunability.The operation principle is explained in detail.By adjusting polarization controllers,multiple logic functions corresponding to different input polarization states are separately achieved using a single SOA with high flexibility.
We propose and experimentally demonstrate mutual optical format conversion between signals characterized as 10-Gb/s nonreturn-to-zero on-of-keying(NRZ-OOK)and NRZ binary phase-shift keying(BPSK)types.The conversion is based on stimulated Brillouin scattering(SBS)in a single-mode optical fber.An OOK signal is converted into a BPSK signal through optical carrier absorption,for which a SBS loss of30 MHz is used in long-haul transmission.The converted BPSK signal is reverted to an OOK signal with a corresponding SBS gain of 30 MHz for direct detection.The proposed OOK-to-BPSK and BPSK-to-OOK format conversions can be implemented in transmitter and receiver nodes by using a laser source as the Brillouin pump.
We propose a stable multi-longitudinal Brillouin/semiconductor fiber laser(BSFL) as the upstream source in a bidirectional single-fiber wavelength-division multiplexing-passive optical network(WDM-PON).The downstream wavelength serves as the pump of the BSFL.Brillouin-frequency-shifted(～10.8 GHz) upstream carrier is generated to suppress the Rayleigh backscattering and back reflection-induced crosstalk.The stable multi-longitudinal operation of the BSFL,attributed to the four-wave mixing(FWM) effect in the semiconductor optical amplifier(SOA) reduces the difficulty of generating a stable single-longitudinal fiber laser-based upstream carrier.Bidirectional symmetric transmission at 10 Gb/s over a 12.5-km single mode fiber with less than 2-dB power penalty is demonstrated.
