The first hybrid-integrated optical phase-lock loop (OPLL) for use in high spectral purity photonic terahertz sources was presented. We have achieved the necessary short loop delay to lock a 1-MHz linewidth slave laser. The laser and photodetectors are InP-based and flip chip bonded to silicon daughter boards, which are in turn attached to the motherboard. Delay between the slave laser and photodiode was approximately 50 ps. The mixing product between slave and master sources has a linewidth of less than 1 kHz and achieved phase noise less than -80 dBc/Hz at an offset of 10 kHz. This integrated OPLL circuit was used with an optical comb source to generate high spectral purity signals at frequencies up to 300 GHz with linewidths less than 1 kHz.
COBISS.SI-ID: 8260948
A classical hierarchical menu structure of MS Word application was presented with multiple simultaneous sounds. In the user study with blind and visually impaired users we evaluated the efficiency of various numbers of simultaneous sounds as well as their spatial distribution (horizontal and vertical). The results demonstrated that the use of multiple simultaneous sounds increases the information flow between user and a computer and improves the navigation but decreases the speed of interaction due to very high cognitive workload.
COBISS.SI-ID: 8085332
The paper presents an analytic derivation of the axis and angle of the single rotation equivalent to three simultaneous rotations around orthogonal axes when the measured angular velocities or their proportions are approximately constant. Based on the resulting expressions, a vector called the simultaneous orthogonal rotations angle (SORA) is defined, with components equal to the angles of three simultaneous rotations around coordinate system axes. The orientation and magnitude of this vector are equal to the equivalent single rotation axis and angle, respectively. As long as the orientation of the actual rotation axis is constant, given the SORA, the angular orientation of a rigid body can be calculated in a single step, thus making it possible to avoid computing the iterative infinitesimal rotation approximation.
COBISS.SI-ID: 8574804