Effect of the Aperture Averaging Technique on Multiple Input Multiple Output (MIMO)-based Mid-wave Infrared (MWIR) and Short-wave Infrared (SWIR) Free Space Optics (FSO) Link in the Presence of Scintillation and Different Visibility Circumstances
S. Mukherjee, S. Paul and S. Mazumdar
The atmospheric scintillation effect on free space optics (FSO) communication link is very detrimental and the bit error rate (BER) reliability of the FSO link has suffered for it. However, by applying the aperture averaging scheme, the detrimental effect of the scintillation is reduced and the performance of BER is improved significantly. In this letter, a higher order multiple input multiple output (MIMO)-based mid-wave infrared (MWIR) (4000 nm) and short-wave infrared (SWIR) (1550 nm) FSO communication wavelengths, the link distance is 5 km and modulation technique, on-off keying (OOK), have been considered. For applying the aperture averaging technique, different diameter aperture size has been considered like 10 cm., 15 cm., and 20 cm. As the aperture size is increased, as a result, the system performance in terms of BER is improved irrespective of different diversity MIMO scheme. In the very clear visibility, clear visibility, and haze weather conditions, the MWIR FSO link shows the better BER performance, whereas, in case of foggy weather condition, the MWIR link works properly but SWIR wavelength link fails in the same visibility condition, same link distance, signal-to-noise ratio (SNR), aperture diameters and MIMO diversity schemes.
Keywords: Interband cascade laser (ICL), quantum cascade laser (QCL), aperture averaging, free space optics (FSO), multiple input multiple output (MIMO), mid-wave infrared (MWIR), short-wave infrared (SWIR), on-off keying (OOK), turbulence, visibility