Evolution between bright and dark pulses in a MoxW_1-xTe₂ based fiber laser

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Mode-locked fiber lasers are crucial for various applications.
• Developing novel saturable absorbers is key to controlling laser output characteristics.

Purpose of the Study:

• To introduce a Mo_xW_1-xTe₂-based nonlinear optical modulator for an erbium-doped fiber laser.
• To investigate the laser's capability to generate diverse pulse formats, particularly dark pulses.

Main Methods:

• Fabrication of a Mo_xW_1-xTe₂ saturable absorber.
• Integration of the absorber into an erbium-doped fiber laser cavity.
• Adjustment of output coupling ratio and polarization controller to observe different mode-locking states.

Main Results:

• The Mo_xW_1-xTe₂ modulator exhibited a modulation depth of 7.8% and saturation intensity of 8.6 MW/cm².
• The laser successfully generated bright pulses, bright-dark pulse pairs, dark pulses, bright-dark-bright pulses, and dark-dark-bright pulses.
• Dual-wavelength domain-wall dark pulses were observed at a high output coupling ratio (70%).

Conclusions:

• Mo_xW_1-xTe₂ is a promising material for saturable absorbers in fiber lasers.
• Increasing output energy ratio enhances the generation of dark pulses.
• The developed fiber laser offers versatile pulse generation capabilities, especially for dark pulses.