Intensity noise of mid-infrared semiconductor cascade lasers: exploring shot-noise-limited operation

In many precision sensing applications, the final detection sensitivity is tightly related to the intensity noise of the laser source, which might represent the ultimate limit to the sensor performance. In this framework, we present here the intensity noise characterization of three different mid-infrared semiconductor devices (two quantum cascade lasers and one interband cascade laser). A fast homemade balanced detection system is used to measure the intensity noise of the emitted radiation over a broad Fourier-frequency range, facilitating the observation of shot-noise-limited radiation under specific measurement conditions and detection efficiency. This study allows for a direct performance comparison of the most widespread laser sources in mid-infrared sensing systems.