Linearized Photonic Microwave and mm-Wave Mixer With Dispersion-Induced Power Fading Compensation

A novel photonic microwave and millimeter-wave (mm-wave) mixer with simultaneous third-order intermodulation distortion (IMD3) suppression and dispersion-induced power fading compensation is proposed and experimentally demonstrated. In our proposed scheme, a dual-polarization quadrature phase shift-keying (DP-QPSK) modulator is used to modulate RF/IF and LO signals. The bias voltages of the main modulators are adjusted to compensate dispersion-induced power fading. When the polarization state of the modulated signal and the attenuation of the RF signal are properly adjusted, IMD3 distortion can be suppressed. In the experiment, relatively flat microwave and mm-wave signals from 11 to 35 GHz are obtained through 4- and 50-km fiber transmission, while the measured spurious free dynamic range (SFDR) is 112.9 dB center dot Hz4/5. In addition, an upconverted 16 quadrature amplitude modulation (16 QAM) vector signal with a carrier frequency of 19.3 GHz is obtained and the measured constellation diagrams and error vector magnitudes are given after transmission over different fiber lengths (back to back, 4 and 50 km).