All-optical harmonic frequency up-conversion for a WDM radio over fiber system

All-optical harmonic frequency up-conversion into millimeter wave frequency over WDM radio over fiber application is demonstrated by using a semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI), which is based on cross phased modulation (XPM) effect in the SOA. Maximum frequency conversion efficiencies from f/sub IF/ to f/sub LO/ /spl plusmn/ f/sub IF/ and 2f/sub LO/ /spl plusmn/ f/sub IF/ are 13.2 dB and 3.1 dB, respectively. The efficiency of 2nd harmonic frequency up-conversion is positive for the IF signal wavelength between 1547.22 nm and 1560.61 nm. The phase noise of the up-converted signal at 2f/sub LO/ /spl plusmn/ f/sub IF/ is -80.0 DBc/Hz with 1 kHz offset frequency, which is limited by that of the LO source.