A Photonic Microwave Frequency Quadrupler With Decoupled Bandwidth and Carrier Frequency for Multi-Octave LFM Signal Generation

A photonic microwave frequency quadrupler with decoupled bandwidth and carrier frequency for multi-octave linear frequency modulated (LFM) signal generation is proposed and experimentally demonstrated. The frequency quadrupler contains two phase-correlated photonic mixers incorporated in a single hardware, which has four input ports and an output port. An intermediate frequency (IF) LFM signal, is frequency doubled and up-converted to a radio frequency (RF) LFM signal which has a flipped frequency slope and doubled bandwidth in one photonic mixer. Then the generated RF LFM is heterodyned with the IF LFM in the other photonic mixer. At the output port, a frequency-quadrupled LFM signal, of which the carrier frequency is independent of the IF LFM and tunable, is obtained. Since the bandwidth and the center frequency of the generated signal are decoupled, a multi-octave signal is generated from a sub-octave signal with the proposed photonic-assisted frequency quadrupler.