Optical clock division based on dual-wavelength mode-locked semiconductor fiber ring laser

Area of Science:

• Photonics and Optical Engineering
• Laser Physics
• Fiber Optic Communications

Background:

• Mode-locked fiber lasers are crucial for generating high-frequency optical clock signals.
• Achieving stable optical clock division is essential for advanced timing and signal processing applications.
• Semiconductor optical amplifiers (SOAs) offer a compact and efficient gain mechanism for fiber lasers.

Purpose of the Study:

• To investigate and demonstrate stable optical clock division using an injected mode-locked fiber ring laser.
• To analyze the underlying mechanism of clock division, focusing on modulation competition between wavelength components.
• To achieve and verify stable second, third, and fourth order clock divisions.

Main Methods:

• Utilized a mode-locked fiber ring laser incorporating semiconductor optical amplifiers (SOAs) and dispersion compensation fiber (DCF).
• Injected a 10-GHz clock signal into the laser cavity.
• Adjusted polarization controllers to manage modulation competition between two wavelength components.
• Analyzed the output using radio-frequency (RF) spectra to confirm clock division quality.

Main Results:

• Successfully achieved stable second, third, and fourth order optical clock divisions.
• Demonstrated that clock division arises from modulation competition between two wavelength components satisfying harmonic mode-locking conditions.
• RF spectra confirmed the high quality and stability of the generated clock division trains.

Conclusions:

• The proposed method using an injected mode-locked fiber ring laser with SOAs provides a robust technique for optical clock division.
• Modulation competition between distinct wavelength components is the key mechanism enabling stable frequency division.
• This approach offers a promising solution for generating precise sub-harmonic optical clock signals for various applications.