A photonic lantern developed by the Instituto de Astrofísica de Andalucía (IAA-CSIC) combines light from seven optical fibers into one multimode output. Laboratory tests reported efficiency above 90%. In an October 28, 2026, release, IAA-CSIC said integration into MARCOT Pathfinder and testing with light from astronomical objects were the next steps.
Seven fibers feed one multimode output
A multimode fiber carries light in multiple optical modes. The Optics Letters paper describes a multimode-to-multimode lantern: it combines several multimode fiber inputs into one multimode waveguide. IAA-CSIC specifies seven inputs for the device.
A 2024 NASA Glenn technical presentation describes a receiver arrangement in which one multimode input transitions to multiple smaller-core fibers. The lantern described by IAA-CSIC instead brings light from several fibers together in one output.
| Architecture | Input | Output | Optical path |
| Receiver arrangement described by NASA Glenn | One multimode fiber | Multiple smaller-core fibers | Incoming light transitions to several output fibers, which can feed detectors or instruments |
| Lantern described by IAA-CSIC | Seven optical fibers | One multimode waveguide | Combines light from the fiber inputs |
What the above-90% result measures
The above-90% figure describes the lantern’s laboratory efficiency. The paper reports measurements after characterizing devices at multiple wavelengths; IAA-CSIC says its laboratory tests retained more than 90% of the light. A component-efficiency measurement describes light passing through the lantern. Telescope sensitivity and resolution are system-level outcomes.
The paper, published in Optics Letters on September 2, 2026, presents the design as a step toward scalable modular telescopes. Its abstract says the architecture does not require diffraction-limited injection, or input light delivered at the telescope’s diffraction limit.
Why multimode light matters for ground-based telescopes
Earth’s atmosphere can alter starlight before it reaches a telescope. IAA-CSIC says multimode fibers can carry that light after atmospheric turbulence has affected it, giving the lantern a way to combine signals from several telescopes without requiring diffraction-limited injection.
Photonic E-MARCOT is developing a modular telescope concept, and MARCOT Pathfinder is its seven-unit demonstrator at Calar Alto Observatory in Almería. The project says Pathfinder commissioning was completed in February 2023, after which it entered routine on-sky operations.
In its October 28 release, IAA-CSIC described integrating this lantern into MARCOT Pathfinder and testing it with light from real astronomical objects as the next steps.
