A 60-GHz optoelectronic mixing scheme of high image and carrier rejection ratios with an integrated optical single-sideband modulator employed

We report on the first implementation and performance investigation of a 60-GHz-band optoelectronic image rejection mixing scheme based on a broad-band integrated optical single-sideband modulator. We have confirmed a few advantageous features over electrical image rejection mixers, arising from its nature of being free from electrical phase control of millimeter-wave signals. We obtained at the IF frequency of 800 MHz rejection ratios of >40 dB for the image signal and of >20 dB for the local oscillator (LO) signal in the LO frequency range of 55-65 GHz. The LO bandwidth can be extended further. The IF bandwidth with an image rejection ratio of >20 dB was also confirmed to be as broad as 550 MHz, which is limited not by the configuration but by the bandwidth of the 90° hybrid used in this experiment. Furthermore, fiber-optic transmission of a 155.52-Mb/s-DPSK 59.8-GHz optical millimeter-wave signal was successfully demonstrated for a 20-km standard single-mode fiber. A bit error rate of <10^-9 was achieved at the received optical power of -18 dBm with a negligible dispersion penalty