Free-space communications and quantum photonics: advancements in mid-infrared interband cascade lasers

In the dynamic field of quantum photonics, our research explores the promising convergence with interband cascade lasers (ICLs), focusing on their applications in free-space communications and quantum photonics. The pressing need for space-to-ground high-speed transmission in the global broadband network development aligns seamlessly with the unique advantages of mid-infrared wavelengths. From minimal atmospheric attenuation to eye-safe operation and resilience against bad weather conditions, mid-infrared wavelengths are expected to provide a robust foundation for these systems. Our work shows that the utilization of interband cascade technology is very much promising for high-speed transmission at a wavelength of 4.2 μm. The low power consumption of both the laser and the detector, combined with a substantial modulation bandwidth and good output power, positions this technology as an ideal solution for free-space optical communications hence enabling multigigabit data rate operations. Concurrently, our research also explores the potential of harnessing squeezed light using high quantum efficiency ICLs. Through a stochastic model approach, we demonstrate that these midinfrared semiconductor devices can exhibit significant amplitude squeezing across a broad bandwidth of several gigahertz when powered by low-noise constant current sources. These collective efforts pave the way for accelerated advancements in mid-infrared ICLs, encompassing both quantum photonics and future free-space laser communication systems include novel quantum key distribution protocols.