Tunable single-mode fiber-VCSEL using an intracavity polymer microlens

Area of Science:

• Photonics and Optics
• Semiconductor Lasers
• Fiber Optic Technology

Background:

• Vertical Cavity Surface-Emitting Lasers (VCSELs) are crucial for various applications but often face limitations in power scaling and fiber coupling.
• Existing VCSEL designs may not be optimal for operation in isolated environments or integration with optical fibers.

Purpose of the Study:

• To report a novel, tunable, single-mode VCSEL format designed for array operation, power scaling, and efficient fiber coupling.
• To demonstrate the feasibility of fiber VCSELs for applications requiring operation in isolated environments, such as atom optics.

Main Methods:

• Fabrication of fiber VCSELs comprising a semiconductor gain and mirror structure separated from a mirror-coated optical fiber by an air/vacuum gap.
• Integration of polymer microlenses onto the VCSEL gain structure to focus the oscillating mode onto cavity mirrors.
• Characterization of device performance in continuous-wave operation.

Main Results:

• Demonstration of fiber VCSELs operating at 1.03 microm at room temperature.
• Achieved a single-mode tuning range of 13 nm.
• Observed a low laser threshold of 2.5 mW and a maximum fiber-coupled output power of 10 mW.
• Confirmed stable fundamental mode emission and high fiber coupling efficiency due to integrated microlenses.

Conclusions:

• The developed fiber VCSEL format is suitable for array operation, power scaling, and efficient fiber coupling.
• These devices offer a promising solution for applications requiring stable, tunable, and high-power laser sources in isolated environments.
• The integrated microlenses are key to achieving stable fundamental mode emission and high coupling efficiency.