Dual-wavelength switchable, mid-infrared quantum cascade laser with two shallow-etched distributed Bragg reflectors

Area of Science:

• Optics and Photonics
• Semiconductor Devices
• Laser Technology

Background:

• Quantum cascade lasers (QCLs) are crucial for mid-infrared (MIR) applications.
• Developing compact, multi-wavelength laser sources is essential for advanced sensing.
• Existing QCLs often lack the flexibility for multi-species detection.

Purpose of the Study:

• To design and fabricate a novel dual-wavelength quantum cascade laser (QCL).
• To achieve independent control over two distinct emission wavelengths within a single device.
• To demonstrate high optical power output for practical applications.

Main Methods:

• Heterogeneous active region design within a single waveguide.
• Integration of two shallow-etched distributed Bragg reflectors.
• Selective current injection for independent wavelength control.
• Fabrication and characterization of the dual-wavelength QCL device.

Main Results:

• Single-mode emission achieved at 7.6μm and 8.2μm.
• Independent wavelength switching demonstrated via selective current injection.
• High room-temperature optical powers of ~275mW (7.6μm) and ~218mW (8.2μm) obtained.
• Successful demonstration of a dual-wavelength, switchable, high-power mid-infrared QCL.

Conclusions:

• The developed dual-wavelength QCL design enables flexible and efficient MIR light generation.
• This technology is significant for developing miniaturized, multi-species gas detection systems.
• The device's performance highlights its potential for various spectroscopic applications.