Photonics-Based Microwave Switching Using Optical Single Sideband Wavelength Conversion in a Semiconductor Optical Amplifier

Photonics-based microwave switching using optical single sideband (OSSB) wavelength conversion in a semiconductor optical amplifier (SOA) is proposed and demonstrated. By using the joint four-wave mixing and self-phase modulation effects in the SOA, the scheme can simultaneously realize the OSSB signal generation and photonic microwave switching, which can minimize the switching crosstalk, since the OSSB signal occupies the least optical bandwidth. This method is also simple as only a single SOA is required. Photonic switching of a 200-Mb/s 16-QAM signal centered at 20 GHz is performed. The signal after switching is an OSSB signal, which has a 22.65- or 17.85-dB sideband suppression ratio for switching based on wavelength down- or up-conversion, respectively. An investigation with the switched signals to combat the dispersion-induced power fading effect for radio over fiber application is also taken. Performance dependence of the optical pump and probe powers, the optical probe-pump power ratio, the modulation depth of the probe signal, and the SOA bias current are also investigated and analyzed.