High-power, narrow-bandwidth, 800-950  nm wavelength-tunable fiber optical parametric oscillator pumped by a spectrally managed Yb-doped fiber laser.

Fiber optical parametric oscillators (FOPOs) offer coherent laser outputs with broad wavelength tunability, high conversion efficiency, and stable operation, which are widely applied in biomedical imaging and wavelength conversion. Here, we report on a high-power, narrow-bandwidth, 800-950 nm FOPO pumped by a picosecond spectrally managed Yb-doped fiber laser. The home-built polarization-maintaining (PM) fiber seed laser was mode-locking based on the nonlinear amplifying loop mirror (NALM). The narrow-bandwidth, high-power fiber pump laser for the FOPO was realized by utilizing the extra-cavity amplified spectral filter consisting of the 4-f spectral filter and the double-pass fiber amplifier. Numerical simulations of the employed four-wave mixing (FWM) process were performed and validated experimentally. The FOPO dynamics governed by the FWM parametric gain were analyzed. The realized FOPO source can deliver a signal laser with central wavelength tuning from 800 to 950 nm, with <1-nm optical spectral bandwidth and >100-mW optical average power. The Yb-doped fiber pump laser can deliver 1040-1060 nm tunable picosecond pulses with watt-level average power and ∼1-nm spectral bandwidth. This compact, robust FOPO laser source fulfills the key requirements for biomedical imaging and nonlinear frequency conversion.