Tunable CW all-fiber optical parametric oscillator operating below 1 μm

Area of Science:

• Optics and Photonics
• Fiber Lasers
• Nonlinear Optics

Background:

• Continuous-wave (CW) all-fiber optical parametric oscillators (FOPOs) are crucial for generating tunable light sources.
• Birefringent photonic crystal fibers offer unique nonlinear properties for parametric processes.

Purpose of the Study:

• To demonstrate a CW all-fiber optical parametric oscillator (FOPO) using birefringent photonic crystal fiber.
• To investigate the tuning range, efficiency, and output power of the developed FOPO.
• To analyze the impact of pump spectrum narrowing on FOPO performance.

Main Methods:

• Utilized an Ytterbium-doped fiber laser (YDFL) as the pump source near 1 μm.
• Employed a birefringent photonic crystal fiber within the FOPO cavity.
• Investigated pump spectrum narrowing to 40 pm to enhance efficiency.

Main Results:

• Achieved a tuning range from 950 to 1010 nm.
• Obtained CW parametric generation with a spectral linewidth of 3.7 nm at 972 nm.
• Demonstrated a slope efficiency of 9.4% and output power up to 460 mW.
• Observed a FOPO slope efficiency of 25% with narrowed pump spectrum, exceeding 1 W output power.
• Noted modulation in generated radiation (48 ns period, 50% duty factor) at higher efficiencies, likely due to stimulated Brillouin back scattering.

Conclusions:

• Successfully demonstrated a tunable CW all-fiber optical parametric oscillator.
• Highlighted the significant efficiency enhancement achievable through pump spectrum narrowing.
• Identified stimulated Brillouin back scattering as a potential limiting factor for high-power, high-efficiency operation.