Free-space optical communication systems always require a precise focusing at the receiver. Unfortunately, when the transmitted beam passes through the atmosphere the wavefront is distorted by the time variant inhomogeneity of the refractive index, causing strong fluctuations in the power coupled into single-mode fiber at the receiver. We present an optical transmission system with a Multi-Actuator Lens (MAL) capable to increase the fiber coupling efficiency from about 5% in absence of correction to the 20%. The measurements have been performed indoor with artificially generated aberrations and outdoor in a 100m horizontal link at 1550nm.
Free-space optical communication systems always require a precise focusing on the receiver to maximize the fiber coupling efficiency. Unfortunately, atmospheric turbulence causes scintillation at the receiver. Ground to ground receivers over short distances (up to 500m) have usually small aperture (about 50mm). In this case the main aberration is tip/tilt and its correction is of fundamental importance for high bandwidth data transmission. We present a new concept of Fast Steering Prism (FSP) for the correction of tilt, suitable for optical communication and optical tracking. The system consists in the use of a novel design of a tunable prism with a variable angle based on the usage of piezoelectric actuators. A system with a FSP has the advantage to be more compact and simpler with respect to the one with a fast-steering mirror. The entire setup has been tested in a 200m outdoor transmission with promising results.
Free-space optical communication systems always require a precise focusing on the receiver to maximize the fiber coupling efficiency. Unfortunately, atmospheric turbulence causes scintillation at the receiver. Ground to ground receivers over short distances (up to 500m) have usually small aperture (about 50mm). In this case the main aberration is tip/tilt and its correction is of fundamental importance for high bandwidth data transmission.
We present a new concept of Fast Steering Prism (FSP) for the correction of tilt, suitable for optical communication and optical tracking. The system consists in the use of a novel design of a tunable prism with a variable angle based on the usage of piezoelectric actuators. A system with a FSP has the advantage to be more compact and simpler with respect to the one with a fast-steering mirror. The entire setup has been tested in a 200m outdoor transmission with promising results.
Long distance imaging and free space optical communications are largely affected by atmospheric turbulence. To attenuate turbulence effects, Adaptive Optics (AO) has been the main answer and, in the case of large FOV Multi Conjugate AO (MCAO) using two deformable mirrors (DM) has been proven to be an effective solution. We present a study and some preliminary results on the use of a stack of Adaptive Lenses (AL) in a MCAO setup with the main advantage of compactness end easiness of installation.
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