Microlens for coupling a semiconductor laser to a single-mode fiber

Area of Science:

• Optoelectronics
• Fiber Optics
• Materials Science

Background:

• Efficient coupling between laser diodes and single-mode fibers is crucial for optical communication systems.
• Traditional coupling methods often suffer from significant losses and misalignment sensitivity.

Purpose of the Study:

• To develop and evaluate a simple method for fabricating conical microlenses on single-mode fibers.
• To enhance the coupling efficiency between laser diodes and single-mode fibers.
• To investigate the impact of lateral misalignment on coupling loss.

Main Methods:

• Fabrication of simple conical microlenses on the end of vapor-axial-deposition single-mode fibers.
• Utilizing a 1.3-microm indium gallium arsenide phosphide (InGaAsP) buried-heterostructure laser diode.
• Experimental measurement of coupling efficiency and loss penalty due to lateral misalignment.

Main Results:

• Achieved a lowest coupling loss of 3 dB.
• Demonstrated the effectiveness of conical microlenses in improving laser-to-fiber coupling.
• Quantified the loss penalty associated with lateral misalignment.

Conclusions:

• Simple conical microlenses offer an effective and reproducible solution for increasing laser diode to single-mode fiber coupling efficiency.
• The fabricated microlenses are easy to manufacture, presenting a practical approach for optical system integration.