High-capacity free-space optical link in the midinfrared thermal atmospheric windows using unipolar quantum devices

Abstract

. Free-space optical communication is a very promising alternative to fiber communication systems, in terms of ease of deployment and costs. Midinfrared light has several features of utter relevance for free-space applications: low absorption when propagating in the atmosphere even under adverse conditions, robustness of the wavefront during long-distance propagation, and absence of regulations and restrictions for this range of wavelengths. A proof-of-concept of high-speed transmission taking advantage of intersubband devices has recently been demonstrated, but this effort was limited by the short-distance optical path (up to 1 m). In this work, we study the possibility of building a long-range link using unipolar quantum optoelectronics. Two different detectors are used: an uncooled quantum cascade detector and a nitrogen-cooled quantum well-infrared photodetector. We evaluate the maximum data rate of our link in a back-to-back configuration before adding a Herriott cell to increase the length of the light path up to 31 m. By using pulse shaping, pre- and post-processing, we reach a record bitrate of 30 Gbit s − 1 for both two-level (OOK) and four-level (PAM-4) modulation schemes for a 31-m propagation link and a bit error rate compatible with error-correction codes.

Novel coding schemes for dual wavelength quantum cascade laser‐based free space optical links

“…The entire study is done with this condition so that an upper hand on the losses and other parameters is derived from this study. More insights on the effect of atmospheric turbulence on the performance of FSO links is reported in detail in References 41–46. Aerosols are tiny solid or liquid particles suspended in the air, such as dust, smoke, fog, or haze.…”

Generation of broadband optical chaos at mid-infrared wavelength with an interband cascade laser

“…Our analysis was indeed partially limited by our (yet very sensitive) HgCdTe detector whose frequency cutoff is below 1 GHz. In the near future, we expect that free-space communication and nonlinear pattern generation in the mid-infrared will greatly benefit from the next generation of detectors based on either frequency-conversion technology, 61 unipolar quantum optoelectronics, 62 or resonant cavities, 63 those already being able to operate at frequencies !5 GHz. In addition, upcoming efforts will study techniques to broaden the mid-infrared chaos bandwidth beyond the GHz range, for instance, by implementing strong optical injection schemes 64 or by filtering and reinjecting residual optical side modes.…”

Advancing LWIR FSO Communication through High-Speed Multilevel Signals and Directly Modulated Quantum Cascade Lasers

“…Due to their longer wavelengths, MWIR and LWIR exhibit elevated resistance against atmospheric turbulence scintillation, and they adhere to a more relaxed eye-safety threshold 11 . Semiconductor optoelectronic components that emit MIR directly offer an alternative for reduced footprint, less energy consumption, and enhanced integrability [12][13] . Recent advancements in quantum optoelectronic devices, like quantum cascade lasers (QCLs), with features such as continuous-wave operation at room temperature, high output power, and broad modulation bandwidth, show capacity for MIR FSO transceiver development 14 .…”