In this letter, we present a non-mechanical 2D beam-steering system suitable for optical wireless communication. Steering is achieved using polarization gratings combined with nematic liquid crystal cells operating as voltage-controlled shifters. These steering elements are holographic diffuser matched to the discrete angles of grating, enabling continuous angular coverage. Beam-steering also u...

The use of optical clocks or oscillators in future ultraprecise navigation, gravitational sensing, coherent arrays, and relativity experiments will require time comparison and synchronization over terrestrial or satellite free-space links. Here, we demonstrate full unambiguous synchronization of two optical time scales across a free-space link. The time deviation between synchronized time scale...

Currently, the modulation performances of underwater wireless optical communication are analyzed in horizontal optical transmission link. However, the methods cannot be used in vertical optical transmission link. In order to solve the problem a model of sea attenuation coefficient is proposed. The model is based on the Gaussian distribution model of chlorophyll concentration and the “seawater s...

Underwater wireless optical communication (UWOC) systems have been identified as a suitable replacement technology with high data rates over relatively medium transmission ranges for underwater communication. In the research, we propose new hybrid modulation format carrying letters system. This combines pulse position (PPM) digital interval (DPIM) to increase transporting speed. The proposed UW...

Deflection routing is one of the promising approaches to resolve contention in the optical burst switching networks. In the conventional deflection routing scheme, optical bursts may be unable to traverse the route evaluated to select an outgoing link because of the contention at succeeding downstream transit nodes. As a result, the optical bursts may traverse a different route resulting in a l...

In space, radio frequencies (RFs) are usually used for long-distance linkage. However, recent progress in optics and laser technologies, especially in fiber optics, is ushering in an era of inter-orbit communications using laser beams. Both RFs and optical waves are electromagnetic waves, but optical waves offer many advantages in space, including reduced mass, power, and volume of equipment, h...