The purpose of GAOM is to design, manufacture and test a generic adaptive optics system prototype, modular in design, compatible with different hosting telescopes and largely based on off-the-shelf components, that can cut recurrent costs.
The key concepts of GAOM are a) to manage both quantum and optical laser communication signals, b) to establish modularity so to accommodate scalable user needs.
The project aims to revisit the generic design of an adaptive optics bench bringing in the concept of scalability and modularity. The final goal is to realize a bench that can manage both optical laser communication signals in up- and downlink as well as quantum communication signals while enabling compensation of atmospheric perturbation for improved fiber coupling. The prototype targets the application on the ESA’s IZN-1 Tenerife station, but one of the objectives is to deliver a concept design that can serve Optical Ground Stations of different sizes and layouts, depending on targeted performances.
Laser and Quantum Communication space assets are increasingly becoming of strategic relevance to guarantee secure communication across the globe.
The development of commercially viable Optical Ground Station solutions is one of the key enablers for this segment in the upcoming years, and reliable, cost effective, commercial adaptive optics modules represent a cornerstone of such development. The objective of GAOM project is to respond to these market challenges by developing such subsystem with a specific focus on Quantum Key Distribution applications.
The challenges of GAOM are the challenges of quantum communication terminals: how to maximize rates for both optical and quantum communication in a broad range of turbulence conditions, meeting high channel isolation, enabling polarization control, with a low SWaP optical layout. In addition, from the view of the OGS operator, one of the challenges is maximizing usability, operability while minimizing maintenance.
The system will enable the supply of classical and QKD optical communication services via the implementation of high efficiency single mode fiber coupling, which will enable daytime QKD operation, translating into higher availability of service. Finally, its high flexibility and modularity and the use of COTS components will guarantee maximum compatibility with existing facilities, which will translate into lower customer lead times and a faster deployment of a widespread global optical and QKD ground station network.
GAOM operates as a bidirectional optical breadboard, thus enabling reception of quantum and classical light from space and transmission of classical beams towards the counterpart satellite. It is designed to be able to interface with a plurality of telescopes with different optical and mechanical configurations and apertures ranging from 600 to 1500 mm.
On the transmitter side, GAOM is designed to launch up to 2 independent beams with optical power of 15W each, with transmitted beam diameters larger than 100mm.
On the receiver side, GAOM routes the incoming beams from the satellites towards single-mode fibers, and employs adaptive optics to correct the incoming wavefront and optimize fiber coupling thus allowing daylight QKD, which is a key feature of the envisaged system.
A critical aspect of the breadboard is related to the optimization of performance of the AO system, which shall cover a broad set of turbulence conditions (up to Fried parameters of 3cm), thus guaranteeing the operation of the OGS with high availability.
Finally, GAOM targets the realization of a modular architecture, which can be configured to comply with missions having different wavelength plans. To this end, GAOM supports QKD operation in three spectral bands (785-815nm, 1530-1537 nm 1567-1570 nm) and Tx transmission and reception compatible with CCSDS standard. All in all, considering both interface and wavelength flexibility, GAOM represents a platform in which system configuration and performances can be adjusted in view of the specific customer needs.
GAOM’s architecture starting point is based on the diagram above, retrieved from SoW. It includes multiple subsystems, which operate together to achieve the final functionalities. Namely, the system is composed by:
Collimator, which receives light from the telescope and creates a pupil, which is further relayed throughout the optical path;
PAT (Pointing Acquisition and Tracking) and AO (Adaptive Optics) subsystem, which senses and corrects the incoming wavefront, and also performs the splitting between different channels;
Tx module, which transmits two separate beams from ground to space.
Fiber coupling subsystem for coupling of classical and quantum signals in the single-mode fiber.
Subsystem controller, managing the operation of the system and interfacing with the OGS controller.
The project follows a traditional development sequence, starting from refinement of specifications and product concept, moving onto product preliminary and detailed design, MAIT and testing.
The project timeline is reported in the bar chart here below.
The following project milestones are planned:
MS 1: Preliminary Design Review (PDR), Q2 2023
MS 2: Critical Design Review (CDR), Q4 2023
MS 3: Factory Acceptance Test / Test Readiness Review (FAT / TRR), Q2 2024
MS 4: Final Settlement, Q4 2024
The project kicked off on October 2022.
Work currently in progress.