Actively mode-locked fiber optical parametric oscillator based on feedback idler

We report an actively mode-locked fiber optical parametric oscillator (FOPO) based on feedback idler which is reflected by a fiber Bragg grating (FBG). The idler-resonant FOPO, configured in ring cavity, is based on high nonlinear fiber (HNLF) and the feedback idler which is modulated by a phase modulator (PM) is poured into the ring cavity via a 3-dB coupler pumped by a continuous wave (CW). With the PM activated and the cavity length synchronized, a stable train of 50 ps pulses can be obtained at a repetition rate of 10 GHz.