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THz quantum cascade lasers with wafer bonded active regions.
M Brandstetter1, C Deutsch, A Benz
1Photonics Institute and Center for Micro- and Nanostructures, Vienna University of Technology, Gusshausstrasse 29, A-1040 Vienna, Austria. martin.brandstetter@tuwien.ac.at
Optics Express
|November 29, 2012
Summary
We developed thicker terahertz quantum-cascade lasers (TQCLs) using wafer bonding. This significantly boosts optical power output by over 2x without impacting performance, enhancing TQCL applications.
Area of Science:
- Physics
- Electrical Engineering
- Materials Science
Background:
- Terahertz quantum-cascade lasers (TQCLs) are crucial for various applications.
- Improving TQCL performance, such as output power, is an ongoing research area.
- Waveguide design significantly influences TQCL efficiency and output characteristics.
Purpose of the Study:
- To investigate the impact of increased active region thickness on TQCL performance.
- To demonstrate a fabrication method for thicker TQCL active regions.
- To enhance optical power generation and reduce losses in TQCLs.
Main Methods:
- Fabrication of TQCLs with a 30 μm thick double-metal waveguide.
- Utilizing a wafer bonding process to stack two 15 μm thick active regions.
- Characterization of optical power, threshold current, and operating temperature.
Main Results:
- Achieved a significant increase in output power (more than a factor of 2).
- Demonstrated reduced waveguide losses due to increased active region thickness.
- Observed improved far-field characteristics owing to a larger facet aperture.
- Maintained maximum operating temperature and threshold current levels.
Conclusions:
- Increasing active region thickness via wafer bonding is an effective strategy for enhancing TQCL output power.
- The demonstrated approach offers a pathway to higher-performance TQCLs without compromising operational parameters.
- This advancement has implications for developing more powerful terahertz sources.
