We describe the rigorous results of a wide-angle laser beam scanner, obtained with the help of the vector refraction theory. Using the rigorous results, the distortion of the beam shape is discussed. The distortion to the beam varies with the different relative angles of double prisms. The scanner expands the beam in some directions while it contracts the beam in other directions. According to the conservation of energy, the distribution of the laser intensity is changed as well.
As a step towards the development of a full scale intersatellite laser communication system, the on-ground simulation experiments and performances validation are necessary in the beginning. In this paper, we designed an optical simulator for on-ground communication performances validation of the free-space laser communication system. The simulator basically consists of a Four-transform lens of big aperture and long focal length and following three optical imaging amplifiers. It becomes possible to evaluate communication-performances of optical terminals by distance transform and background noise simulated. System analysis and simulated experiments show that the simulator is feasible and has the great potential for wide applications.
It is required for the laser communication that laser beam transmitted from the optical terminal must be highly parallel. Optical diffraction limit angle is the minimum divergence the beam can obtain while limited by the definite aperture under ideal conditions, here wavefront still has an error of 0.3 wave. This paper introduces a new method for wavefront analysis. In this method a circular aperture diaphragm used to sample the tested wavefront, a focusing lens, a microscope objective and a fiber optic probe are arranged coaxial. Axial intensity profile behind the focusing lens is plotted by registering the positions of the microscope objective on the axis and the readings of the radiometer. The sampled wavefront height is estimated from the distance between two symmetrical positions along the axis where the intensity is zero. The tested wavefront height is calculated from the sampled wavefront height. The theory and the simulation results are given. It can be applied in coarse measurement of any wavelength laser wavefront. Due to simplicity of the method and its low cost, it is a promising method for checking the collimation of a laser beam.
This paper gives the general formula of modulation transfer function for the CCD pixels with arbitrary geometric shape. Based on the formula the modulation transfer functions of CCD are compared between the square and trapezoid pixels with square sampling array. The results show that the modulation transfer function of the square pixel is better than the one of trapezoid pixel.
This paper studied the image-forming characteristic of a CCD and discussed the influence of the carrier diffusion on the single pixel and whole array of CCD. Other factors have also been studied such as quantum efficiency, charge transfer, different kinds of CCD channels and the phase match between input signal and CCD pixel. Basing on above works the comprehensive model has been proposed for modulation transfer function of non-ideal CCD.