Using multiple mutually incoherent fiber lasers to pump a coherent signal beam in an optical parametric oscillator

We use three-dimensional numerical modeling to show that multiple mutually incoherent lasers can be used to pump a single resonated coherent signal beam in an optical parametric oscillator (OPO). We consider as an example an OPO based on periodically poled lithium niobate pumped noncollinearly by CW Yb-doped fiber lasers. Our modeling, which neglects thermal lensing, is appropriate when the average power is kept low by chopping or pulsing the pump beams at a low duty cycle. We find that a signal beam can be produced with near-diffraction-limited beam quality and power considerably exceeding that of a single pump laser.