Generation of Multi-Format Linearly Chirped Microwave Waveform Based on Dual-Domain Mode-Locked Optoelectronic Oscillator

The generation of multi-format linearly chirped microwave waveforms (LCMW) based on dual-domain mode-locked optoelectronic oscillator (DDML OEO) is numerically and experimentally demonstrated. In the DDML OEO, the frequency domain mode locking (FDML) can be implemented using a frequency-scanning microwave photonic filter (MPF), which is realized based on a chirped laser diode (LD). The time domain mode locking (TDML) is realized by the period loop loss modulation via the intensity modulation of a dual-drive Mach-Zehnder modulator (DDMZM). The phase domain mode locking can be achieved using the phase modulation in the DDMZM. Controlling the OEO working at a time-frequency domain mode-locking (TFDML) state, pulsed LCMW or multi-band pulsed LCMW signals are generated when fundamental or ultra-high-order harmonic TDML is implemented. Controlling the OEO working as a phase-frequency mode locking (PFDML) state, a phase-coded LCMW signal is generated. In the experiment, a pulsed LCMW signal with a bandwidth of 8 GHz, a pulse width of 7.5 μs, and a repetition period of 12.3 μs is generated. A five-band pulsed LCMW signal is generated, and each band has a bandwidth of 1.3 GHz and a pulse repetition period of 0.41 ns. A phase-coded LCMW signal with a phase coding rate of about 50 Mb/s, a bandwidth of 2.3 GHz, and a repetition period of 12.3 μs is generated.