4 results about "Free space propagation" patented technology

An interface device for performing off-chip coupling in optical waveguides includes an optical waveguide core for propagating light of a particular wavelength or a plurality of wavelengths and an array of radiative elements configured to change the propagation direction of the light. The optical waveguide core is configured to control the effective refractive index of the propagation mode of the light. The device can thus serve as an optical antenna for coupling between a waveguide mode and a free-space propagating beam or a plurality of free-space propagating beams in an arrayed configuration.

This invention discloses a small airborne laser communication terminal based on single-mode transmission and multi-mode reception, including a signal transmission and beacon transmission module and a signal reception and beacon reception module. The beacon light in the signal transmission and beacon transmission module is emitted at a specific half-divergence angle, and the signal light is also emitted at a specific half-divergence angle. After propagating a certain distance in free space, the signal light and beacon light are received by the receiving telescope, which focuses the beacon light onto the camera target surface. The pointing angle of the three-axis gimbal is driven based on the position error signal of the beacon light spot, completing the bidirectional alignment of the telescope. This invention employs a small and lightweight laser communication system, which improves fiber coupling efficiency, reduces signal light link loss, and has better robustness to atmospheric turbulence and platform vibration, making it suitable for use on UAVs for free-space optical communication experiments.

This invention discloses a method for active interference signal-to-interference ratio (SIR) analysis of aircraft radio communications. The method includes: acquiring aircraft track data, ground station coordinate data, and interference source coordinate data, and mapping them uniformly to a three-dimensional coordinate system; obtaining the interference limit of the interference source at a reference distance and obtaining the reference interference field strength at the reference distance through correction processing; constructing a free-space propagation model of the active interference source, calculating the minimum distance between the aircraft's track point and the interference source, and obtaining the interference signal strength at the track point from the free-space propagation model; calculating the signal strength between the ground station and the aircraft at the track point, and calculating the SIR in decibels at the aircraft's airborne receiver at the track point. This invention can quickly generate SIR curves for interference assessment analysis of different interference sources on aircraft at different flight segments or different locations, significantly improving the accuracy and comprehensiveness of active interference analysis for airborne equipment.

This invention relates to the field of waveguide laser technology, comprising a pair of parallel, oppositely arranged electrode plates, spaced apart to form a waveguide gap; resonant cavities are provided at both ends of the two electrode plates along their length; an insulating coating is provided on the inner surface of at least one electrode plate corresponding to the beam waist region of the resonant cavity; the insulating coating is used to locally weaken the constraint of the electric field on this region by utilizing the difference in conductivity between itself and the electrode plates, forming a free-space-like propagation region with an electric field strength lower than the surrounding region, thereby preferentially selecting the lowest-order waveguide mode for propagation. This invention significantly improves the suppression capability of higher-order modes, avoids the processing difficulty and loss problems caused by excessively small gaps, significantly improves the long-term operational stability of the device, increases the laser damage resistance threshold by approximately 40%, and improves surface thermal conductivity by approximately 25%, thereby effectively extending the device's lifespan.