Experimental studies of a deformable-mirror adaptive optical system*

Pearson, James E.; Hansen, S.

doi:10.1364/josa.67.000325

Cited by 64 publications

(18 citation statements)

References 7 publications

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“…The ratio of these two deflections is defined as the actuator coupling and a 5-12% actuator coupling offers the best correction capability. 18 The above parameters are determined by both the structural design and the fabrication process. Therefore, in this design section, these parameters are considered as a basis for the structural design.…”

Section: Designmentioning

confidence: 99%

A 45-element continuous facesheet surface micromachined deformable mirror for optical aberration correction

Wang

et al. 2014

AIP Advances

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A 45-element continuous facesheet surface micromachined deformable mirror (DM) is presented and is fabricated using the PolyMUMPs multi-user micro-electro-mechanical system processes. The effects of the structural parameters on the characteristics of the DM, such as its stroke, frequency and actuator coupling, are analyzed. In addition, the DM design has also been verified through experimental testing. This DM prototype has a surface figure of 0.5 μm and a fill factor of 95%. The DM can provide a 0.6 μm stroke with 5.9% actuator coupling. A static aberration correction based on this DM is also demonstrated, which acts as a reference for the potential adaptive optics (AO) applications of the device.

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Section: Designmentioning

confidence: 99%

A 45-element continuous facesheet surface micromachined deformable mirror for optical aberration correction

Wang

et al. 2014

AIP Advances

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“…1b). Although this concept of wave-front control without wave-front measurements has been known since the early stages of AO technology development [8][9][10], it was largely disregarded because estimation techniques for the gradient of the metric (cost function) in respect to the control signals imposed limitations for the control bandwidth [11,12].…”

Section: Adaptive Optics Architectures For Free-space Optical Communimentioning

confidence: 99%

Free-space laser communications with adaptive optics: Atmospheric compensation experiments

Weyrauch

Vorontsov

2004

J Optic Comm Rep

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Refractive index inhomogeneities of the turbulent air cause wave-front distortions of optical waves propagating through the atmosphere, leading to such effects as beam spreading, beam wander, and intensity fluctuations (scintillations). These distortions are responsible for severe signal fading in free-space optical communications systems and therefore compromise link reliability. Wave-front distortions can be mitigated, in principle, with adaptive optics, i.e., real-time wave-front control, reducing the likeliness of signal fading. However, adaptive optics technology, currently primarily used in astronomical imaging, needs to be adapted to the requirements of free-space optical communication systems and their specific challenges.In this chapter we discuss a non-conventional adaptive optics approach that has certain advantages with respect to its incorporation into free-space optical communication terminals. The technique does not require wave-front measurements, which are difficult under the strong scintillation conditions typical for communication scenarios, but is based on the direct optimization of a performance quality metric, e.g., the communication signal strength, with a stochastic parallel gradient descent (SPGD) algorithm.We describe an experimental adaptive optics system that consists of a beamsteering and a higher-resolution wave-front correction unit with a 132-actuator MEMS piston-type deformable mirror controlled by a VLSI system implementing the SPGD algorithm. The system optimizes the optical signal that could be coupled into a single-356 Thomas Weyrauch and Mikhail A. Vorontsov mode fiber after propagating along a 2.3-km near-horizontal atmospheric path. We investigate characteristics of the performance metric under different atmospheric conditions and evaluate the effect of the adaptive system. Experiments performed under strong scintillation conditions with beam-steering only as well as with higherresolution wave-front control demonstrate the mitigation of wave-front distortions and the reduction of signal fading.

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“…However, Bushnell [7] characterizes some of these (e.g. [12,13]) as displacement actuators because they are stiff enough to enforce prescribed displacements. Another variation of the force actuator in a truss structure is one which changes the length of a member by reeling a cable in or out or by using a screw mechanism.…”

Section: List Of Symbolsmentioning

confidence: 99%

Effect of sensor and actuator errors on static shape control for large space structures

Haftka

Adelman

1987

AIAA Journal

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This paper is concerned with quantifying the effect of sensor and actuator errors on the ability of thermal control actuators to correct static shape distortion of orbiting spacecraft such as large space antennas.Expressions for the statistical properties of the control effectiveness are derived based on the assumption of normally distributed errors.An example of a 55m space-truss parabolic antenna distorted by orbitalheating is used to demonstrate the effect of sensor and actuator error. It is found that in the case of even moderately large errors, increasing the number of actuators does not always enhance shape control. LIST OF SYMBOLS

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Experimental studies of a deformable-mirror adaptive optical system*

Cited by 64 publications

References 7 publications

A 45-element continuous facesheet surface micromachined deformable mirror for optical aberration correction

A 45-element continuous facesheet surface micromachined deformable mirror for optical aberration correction

Free-space laser communications with adaptive optics: Atmospheric compensation experiments

Effect of sensor and actuator errors on static shape control for large space structures

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