Image intensity recovery with mitigation in the presence of gamma–gamma atmospheric turbulence using encrypted chaos

Abstract

Mitigation of image distortion under modified von Karman-type phase turbulence has been examined by using acousto-optic (A-O) chaos waves generated via feedback in a Bragg cell. The chaos wave transferred to the optical carrier either over an image-bearing transparency (with the image reconstructed with appropriate lensing), or alternatively the two-dimensional image (both static as well as dynamic) is embedded in the chaos wave and propagated over the turbulent layer. These investigations demonstrate that the properties of chaos waves including relative immunity from variations in the propagation path enable reduction or mitigation of the image distortion under turbulent conditions. Mitigation of image distortion is explored using propagation through a turbulent atmospheric layer characterized by gamma-gamma type intensity fluctuations. Standard weak, moderate, and strong turbulence conditions are applied for the numerical analysis based on the corresponding structure parameters. Following standard approach, the relevant probability density functions are generated using small-and large-scale eddies (α and β numbers) incorporated into the turbulence model. In addition, mitigation of image distortion due to gamma-gamma turbulence is examined for propagation along a low-altitude slanted path with a fixed slope and different elevation angles using A-O chaos along with the Huffnagel-Valley model. Stationary images are transmitted under nonchaotic and chaotic conditions, and the corresponding distortions in the received images are measured using the conventional metric of bit error rates. The system performances under nonchaotic and chaotic transmissions are compared with the intent to establish that packaging a signal within a chaos wave offers a degree of distortion mitigation.

A Secure Optical Body Area Network Based on Free Space Optics and Time-Delayed 2D-Spectral/Spatial Optical CDMA

“…Various hardware based techniques were reported exploiting optical chaos, pulse position modulation (PPM), quantum communication, and OCDMA for security of data in OBANs from interception by eavesdropers. Past works based on optical chaos [14][15][16][17], PPM [11], quantum communication [18,19], and OCDMA [2,20,21] were proposed. Optical chaos, quantum communication, and PPM based encryption technologies usually provide good data privacy but face the issues of chaos synchronization, quantum entanglement, and requirement of synchronizing pulses to operate the timing circuits in the receiver, respectively [22].…”

A Secure Optical Body Area Network Based on Free Space Optics and Time-Delayed 2D-Spectral/Spatial Optical CDMA

“…Various hardware based techniques have been reported exploiting optical chaos, pulse position modulation (PPM), quantum communication, and OCDMA for data security in OBANs from interception. Past works have proposed approaches on optical chaos [22][23][24][25], PPM [19], quantum communication [26,27], and OCDMA [2,28,29]. Encryption technologies based on optical chaos, quantum communication, and PPM usually provide good data security; however, they face issues around chaos synchronization, quantum entanglement, and the need to synchronize pulses in order to operate the timing circuits in the receiver, respectively [30].…”