Transportable optical ground station for QKD using adaptive optics with a plenoptic wavefront sensor
Jorge Socas, Joan Torras, Luis Fernando Rodriguez +8 more
The Institute of Astrophysics of the Canary Islands, IAC, and specifically its technology transfer division IACTEC, has a long history of participation in free-space optical communications projects (FSOC). These activities are nowadays being pushed forward to achieve practical applications of quantum key distribution, leveraging its facilities and experience in the FSOC field and its “know-how” in Adaptive Optics. A Free-Space Communications Laboratory has been installed at IACTEC clean rooms, intended to be used as a permanent facility where specific equipment for optical communications, quantum and classical, is available to our research and development group and its collaborators. Single photon detectors and sources, including both avalanche and superconducting nanowires(SNSPD), 16 GHz oscilloscope, FPGA-based time to digital converter, and many optical and electronic general-purpose building blocks are examples of the items existing at the facility, which should become a complement of the existing OGS telescope located at the Observatorio del Teide. The main objective of the group is to make extensive use of the well-known adaptive optics techniques for the compensation of the aberrations introduced in the communications channel by the atmospheric turbulence. Specifically, a Transportable Optical Ground Station (TOGS) with adaptive optics will be presented, designed with the aim to provide efficient transmission of quantum keys between islands or from a LEO satellite. The efficiency of coupling the received signal to a Single Mode Fibre is vital when using a SNSPD because they are commonly used as input to the cryostat, in order to minimize dark counts. When the communication optical link is expected to suffer atmospheric turbulence during its free-space path, being able to compensate them using adaptive optics could improve the coupling efficiency by a factor of 25 for a 1-meter telescope, as has been obtained in simulations carried out by our group. Our group has also found in simulations that an adaptive optics system based on the plenoptic camera will behave especially well in the situation of high turbulence, as it can be expected for sea-level communications. An optical design based in the use of the plenoptic camera as wavefront sensor for the TOGS will be presented.
International Conference on Space Optics (ICSO)•Jul 12, 2023•0 citations