Few-mode polymer waveguide amplifier with a dual-layer coronal refractive index profile.

Area of Science:

• Optoelectronics
• Waveguide Engineering
• Materials Science

Background:

• Few-mode fiber amplifiers are crucial for optical communication systems.
• Equalizing modal gains is essential for high-performance amplification.
• Polymer materials offer advantages in processing and refractive index tuning.

Purpose of the Study:

• To propose and demonstrate a novel few-mode waveguide amplifier with a dual-layer coronal core.
• To equalize modal gains using refractive index profile reconfiguration.
• To investigate the performance of the amplifier with different pumping schemes and powers.

Main Methods:

• Utilizing a polymer with advantageous processing and refractive index properties.
• Optimizing the waveguide design using a genetic algorithm.
• Fabricating the waveguide with accurate alignment mask and characterizing modal profiles and crosstalk.

Main Results:

• Achieved an average gain of 11.84 dB per mode.
• Obtained an ultralow differential modal gain of 0.36 dB.
• Demonstrated effective modal gain equalization through refractive index profile reconfiguration.

Conclusions:

• The proposed dual-layer coronal core few-mode waveguide amplifier is a novel and effective solution for optical amplification.
• The use of polymer and genetic algorithm optimization enables efficient design and fabrication.
• Backward pumping schemes show promising results for high-performance few-mode amplification.