Photonic Microwave Generation With Frequency Octupling Based on a DP-QPSK Modulator

A photonic microwave signal generation scheme with frequency octupling is proposed and experimentally demonstrated using a dual-polarization quadrature phase shift keying modulator. By properly setting the phase difference between the two drive signals, the working points of the modulator, and the polarization state of the light wave after the modulator, an optical signal with only +/- 4th order sidebands is generated. A pure 24-GHz microwave signal with low-phase noise is experimentally obtained using a 3-GHz local oscillator signal. The proposed photonic frequency octupling system also exhibits good frequency tunability as no electrical or optical filter is used.