High-frequency operation of a mid-infrared interband cascade system at room temperature

The high-frequency operation of a mid-infrared interband cascade system that consists of a type-I interband cascade laser and an uncooled interband cascade infrared photodetector (ICIP) is demonstrated at room temperature. The 3-dB bandwidth of this system under direct frequency modulation was ∼850 MHz. A circuit model was developed to analyze the high-frequency characteristics. The extracted 3-dB bandwidth for an uncooled ICIP was ∼1.3 GHz, signifying the great potential of interband cascade structures for high-speed applications. The normalized Johnson-noise-limited detectivity of these ICIPs exceeded 109 cm Hz1/2/W at 300 K. These results validate the advantage of ICIPs to achieve both high speed and high sensitivity at high temperatures.