Tip-Tilt Mirror Control Based on FPGA for an Adaptive Optics System

Abstract

the most logical solution. However, when heavy data This paper describes the development of the tip-tilt mirror processing is needed, some doubts arise about the FPGAs control for an adaptive optics system based on the use of capabilities. Our experience is that for applications such as FPGA technology instead of using the traditional approach adaptive optics, where a lot of parallel processing is needed, with DSP or microprocessor. the use of FPGAs becomes a very attractive alternative,The aim of this work is to show that for this kind of capable of carrying out all the processing and even application the FPGA technology is not only a viable outperforming the DSP behavior when the amount of data solution but probably also the best one in some situations, increases in an important way. The FPGAs allow us to especially when a huge amount of parallel data processing reach the best trade-off for a particular application between is needed. This will probably be the case of adaptive optics more parallel processing and chip area, i.e., we can increase systemsfor verylarge telescopes (1).the level of parallelism at the expense of more FPGA A brief description of the whole adaptive optics system resources.will be given although the paper will focus especially on the One of the drawbacks argued by some people against tip-tilt mirror control and its implementation with FPGAs.

Intensity feedback-based beam wandering mitigation in free-space optical communication using neural control technique

“…ChipScope tools are used to avail the auxiliary modules in the FPGA. The entire control setup is assembled on the optical breadboard inside the laboratory and the experiment is conducted [12]. Digital architectures developed in the FPGA for optical wavefront correction are described by K. Kepa et al The design of the low-cost adaptive optics control system architecture is explained and the results are presented and analyzed.…”

“…These are all the general problems that require attenuation to be dealt with. The major effects due to the random fluctuations of the atmospheric turbulence are (i) optical scattering and observation (characterized by atmospheric attenuation); (ii) random optical power fluctuation (characterized by scintillation index); (iii) beam wandering, i.e., beam surface global (temporal) tilt due to beam centroid displacement on the detector plane (characterized by effective scintillation index); and (iv) wavefront distortions, i.e., beam surface (spatial) local tilt (characterized by the Zernike polynomials) [10][11][12]. The conventional data coding and/or modulation techniques can be used to equalize/compromise the first two effects with respect to weather conditions at a given instant of time [13,14].…”

“…The existence of a perfect LoS and continuous beam alignment between the communicating optical antennas is one of the key requirements for a successful installation of an FSOC system. To ensure an uninterrupted data flow, auto-alignment transmitter and receiver modules are necessary [12,17,18]. The data loss due to weak scintillation effects can be recovered using various data coding techniques developed for wire-and fiber-based communication systems [13,14].…”

“…The data loss due to weak scintillation effects can be recovered using various data coding techniques developed for wire-and fiber-based communication systems [13,14]. In contest, beam wandering and deep signal fading (wavefront distortions) represent unique and significantly more challenging problems, which cannot be resolved using conventional data coding techniques, and a major incentive for the incorporation of adaptive optics technology (beam wandering mitigation and wavefront corrections) into the FSOC architecture is an active prevention of long-term data loss [12,15,16]. The first and most important requirement for the successful installation of FSOC is beam steering (reduction of focal spot wander) that mitigates the beam wandering (temporal distortions) [1,[16][17][18] which is the research component and main contribution in this work.…”

Design of Cognitive Decision Making Controller for Autonomous Online Adaptive Beam Steering in Free Space Optical Communication System

“…Existence of LoS and continuous alignment between the communicating antennas is one of the key requirements for successful implementation of FSOC system. To ensure uninterrupted data flow, autoalignment transmitter and receiver modules are necessary [7,8]. The data loss due to weak scintillation effects can be recovered using various data coding techniques developed for wire and fiber based communication system.…”