All-fiber fourth and fifth harmonic generation from a single source.

Area of Science:

• Photonics
• Nonlinear Optics
• Fiber Optics

Background:

• Efficient generation of higher-order harmonics is crucial for various photonic applications.
• All-fiber systems offer advantages in stability, compactness, and cost-effectiveness compared to bulk optics.

Purpose of the Study:

• To demonstrate and theoretically analyze all-fiber fourth and fifth harmonic generation from a single source.
• To investigate the feasibility of using optical microfibers for generating third and fourth harmonics via four-wave mixing (FWM).

Main Methods:

• Utilizing a high-power master oscillator power amplifier (MOPA) fiber laser system.
• Employing a periodically poled silica fiber for second harmonic generation (SHG).
• Using two distinct optical microfibers for third and fourth harmonic generation through phase-matched FWM.

Main Results:

• Successful experimental demonstration of all-fiber fourth and fifth harmonic generation.
• Achieved phase-matched FWM in microfibers with wide fabrication tolerances (+/-5 nm) for various pump wavelengths.
• Theoretical simulations predict achievable conversion efficiencies exceeding 25% for fourth harmonic generation with optimization.

Conclusions:

• The proposed all-fiber approach provides a robust and efficient method for generating multiple harmonic frequencies.
• The use of optical microfibers offers a scalable platform for nonlinear frequency conversion.
• This work lays the foundation for developing compact and versatile fiber-based light sources for advanced applications.