Sinusoidal Frequency-Modulated Waveforms Generated by a Phase-Modulated Frequency-Shifting Loop

We theoretically and experimentally investigate a phase-modulated frequency-shifting loop (PM-FSL) that includes an electro-optic phase modulator (EOPM) gain element, is seeded by single-frequency laser. By slightly detuning the modulation frequency of EOPM off integer multiple fundamental frequency, we generate output waveform exhibits series pulse doublets modulated at radio (RF). prove consists sinusoidal frequency-modulated (SFM) whose repetition rate bandwidth are easily reconfigurable. report generation SFM waveforms with above 7 GHz (limited detection bandwidth) simply tuning input RF tone over span few kHz in vicinity 14.58 MHz (the round-trip frequency). The system modeled using time-delayed interference model accounts for function EOPM, delay time, parameter. explains formation effectively reproduces all experimental waveforms. This well-defined may find applications RF-optical signal processing radar systems.