Watt-Level Continuous-Wave Emission from a Bifunctional Quantum Cascade Laser/Detector.

Area of Science:

• Photonics and Optoelectronics
• Mid-Infrared Technologies
• Integrated Optics

Background:

• Bifunctional active regions enable integrated photonics for sensing by performing both light generation and detection at the same wavelength.
• Mid-infrared (mid-IR) photonics is crucial for various sensing applications.
• Realizing bifunctional devices at longer wavelengths presents significant challenges in wavelength matching.

Purpose of the Study:

• To present a high-performance bifunctional device for mid-infrared sensing applications operating at 8 micrometers.
• To demonstrate the feasibility of bifunctional operation at longer wavelengths with negligible performance loss.
• To enable sensing techniques requiring continuous wave (CW) operation, such as heterodyne detection, on a monolithic platform.

Main Methods:

• Development and characterization of a novel bifunctional semiconductor device.
• Testing of the device's performance in continuous wave (CW) laser emission at 8 micrometers.
• Evaluation of the device's efficiency and comparison with existing Quantum Cascade Lasers (QCLs).

Main Results:

• Achieved 1 W single facet CW emission at 15 °C for the bifunctional device operating at 8 micrometers.
• Demonstrated that bifunctional operation is feasible at longer wavelengths without significant performance degradation.
• The device exhibits comparable or higher efficiency than state-of-the-art lattice-matched QCLs lacking detection capabilities.

Conclusions:

• The developed bifunctional device offers a promising solution for integrated mid-infrared photonics and sensing.
• The device's performance supports the realization of advanced sensing techniques like heterodyne detection on a monolithic platform.
• This work validates the potential of bifunctional devices for longer wavelength applications, overcoming previous limitations.