Satellite constellations, whether for high-speed Internet access or for Earth observation using high-resolution imagery, are leading to a sharp increase in the volume of data to be brought back to Earth. To meet the needs of these very high-speed communication links, from 10 Gbps to 1 Tbps, optical technologies are becoming essential. Radio frequency technologies currently in use can no longer cope with such data rates without threatening the allocation of frequencies on Earth (5G-6G) or in space. However, to work at high debit rates, broadband optical communication systems require small detectors, high performance amplifiers or coherent modulation schemes needing high efficiency coupling into SMFs, which is subject to atmospheric turbulence. Using Cailabs' core technology, Multi-Plane Light Conversion (MPLC), followed by a photonic integrated chip optical recombiner, we have developed and qualified a unique component for turbulence compensation. This architecture provides high-speed turbulence mitigation at several kHz with the advantage of a single SMF output. In this paper, we investigate the fading improvement provided by this system over direct single mode fiber coupling under various environmental conditions and technical implementations. This system is tested on a km-long test link at Cailabs at up to 10 Gbps under appropriate environmental conditions and at higher debit rates on a turbulence emulation bench. Several configurations are evaluated, including several levels of turbulence. Meanwhile, Cailabs is building its first optical ground station for the LEO-ground optical link. We will present the first experimental results obtained and the roadmap for satellite-ground communication.
Laser Beam Welding (LBW) of complex materials, such as ferritic and austenitic steel, is challenging. An appropriate beam shape improves the process by stabilizing the keyhole.
A methodology for tailoring the beam shape has been developed. The appropriate shape for LBW of 1mm thick steel is an inner intense spot and a background top-hat shape.
A dynamic beam shaper based on Multi-Plane Light Conversion has been developed: the ratio between the shapes and the back shape dimensions can be adjusted. The optical performance and the impact on the quality of the process with a 8kW 1.07µm laser are described.
Space-to-ground laser communication is booming thanks to high throughput, stealth communication without frequency allocation. However, lasercom becomes really competitive beyond 10 Gbps. At this rate, fiber components, requiring SMF coupling, and thus turbulence mitigation become necessary.
Based on Cailabs' core technology, Multi-Plane Light Conversion (MPLC) followed by photonic integrated chip, Cailabs develops a turbulence mitigation product entirely dedicated to lasercom. Previous work showed proof of concept for the 8-mode version. In this article we investigate last results obtained with the system including 100 Gbps communication and present the new 45-modes turbulence mitigation version.
We demonstrate turbulence mitigation in a free-space optical link without adaptive optics. A module consisting of an 8-mode Multi-Plane Light Conversion (MPLC) device connected to a photonic integrated chip (PIC) collects a perturbed beam and converts it into a fundamental mode propagating in a standard single-mode fiber (SMF). Module is tested on a 200-meter optical link at 1550 nm under different D/r0 conditions. Results are compared to simulations and laboratory experiments using calibrated turbulent phase plates. We show increased coupling efficiency and lower fading compared to SMF coupling, demonstrating that MPLC and PIC are a viable turbulence mitigation option.
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