High Frequency Mid-infrared Quantum Cascade Laser Integrated with Grounded Coplanar Waveguide Transmission Line

In this letter, we proposed a kind of high-bandwidth directly modulated quantum cascade laser (QCL) at ~8.5 μm by optoelectronic fusion integration technology. Multi-physics collaborative buried heterojunction (BH) QCL with a tri-terminal coplanar electrode is monolithically integrated with a grounded coplanar waveguide (GCPW) transmission line. Through precise control of each parasitic parameter, has enabled our 2-mm-long and 7.8-μm-wide QCL to achieve an impressive -3 dB electrical modulation bandwidth of 16.5 GHz in a microwave rectification scheme. Simultaneously, it maintains a continuous wave (CW) output power of 91 mW at room temperature. Additionally, for a 2-mm-long and 11.5-μm-wide QCL, we reach a -3 dB electrical modulation bandwidth up to 23.9 GHz and a cutoff frequency exceeding 30 GHz. These promising results indicate that the device has the potential to be a valuable candidate for applications in mid-wave infrared (MWIR) free-space optical communication (FSOC), among others.