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Telescopes and Adaptive Optics

Review of optical interferometry J.Monnier et al 2023

Fiber coupling Seeing-limited Coupling of Starlight into Single-mode Fiber with a Small Telescope

Photonic Lanterns

The photonic lantern

T. A. Birks, I. Gris-Sánchez, S. Yerolatsitis, S. G. Leon-Saval, and R. R. Thomson, Adv. Opt. Photon. 7, 107-167 (2015)

Photonic lanterns are made by adiabatically merging several single-mode cores into one multimode core. They provide low-loss interfaces between single-mode and multimode systems, where the precise optical mapping between cores and individual modes is unimportant.


Photonic Lanterns

Leon-Saval, Sergio G.,  Nanophotonics, vol. 2, no. 5-6, 2013, pp. 429-440.

Multimode optical fibers have been primarily (and almost solely) used as “light pipes” in short distance telecommunications and in remote and astronomical spectroscopy. The modal properties of the multimode waveguides are rarely exploited and mostly discussed in the context of guiding light. Until recently, most photonic applications in the applied sciences have arisen from developments in telecommunications. However, the photonic lantern is one of several devices that arose to solve problems in astrophotonics and space photonics. Interestingly, these devices are now being explored for use in telecommunications and are likely to find commercial use in the next few years, particularly in the development of compact spectrographs. Photonic lanterns allow for a low-loss transformation of a multimode waveguide into a discrete number of single-mode waveguides and vice versa, thus enabling the use of single-mode photonic technologies in multimode systems. In this review, we will discuss the theory and function of the photonic lantern, along with several different variants of the technology. We will also discuss some of its applications in more detail. Furthermore, we foreshadow future applications of this technology to the field of nanophotonics.


Free-space to single-mode collection efficiency enhancement using photonic lanterns

Ibrahim Ozdur, Paul Toliver, Anjali Agarwal, and T. K. Woodward, Opt. Lett. 38, 3554-3557 (2013)

We demonstrate single-mode collection efficiency enhancement for free space optical systems using a photonic lantern to collect scattered infrared light from diffuse objects at far- and near-field distances. A single-mode collection efficiency improvement of ∼8  dB
 is demonstrated in the near-field region relative to standard single-mode fiber. The insertion loss properties of the photonic lantern are also analyzed, and an additional insertion loss penalty is observed for near-field distances when the transmitted beam is collimated. The photonic lantern can be used for coherent detection systems such as light detection and ranging and free-space optical communication with improved collection efficiency and nearly perfect mode matching.


Demonstration of high-efficiency photonic lantern couplers for PolyOculus

Christina D. Moraitis, Juan Carlos Alvarado-Zacarias, Rodrigo Amezcua-Correa, Sarik Jeram, and Stephen S. Eikenberry, Appl. Opt. 60, D93-D99 (2021)

The PolyOculus technology produces large-area-equivalent telescopes by using fiber optics to link modules of multiple semi-autonomous, small, inexpensive, commercial-off-the-shelf telescopes. Crucially, this scalable design has construction costs that are >10× lower than equivalent traditional large-area telescopes. We have developed a novel, to the best of our knowledge, photonic lantern approach for the PolyOculus fiber optic linkages that potentially offers substantial advantages over previously considered free-space optical linkages, including much higher coupling efficiencies. We have carried out the first laboratory tests of a photonic lantern prototype developed for PolyOculus, and demonstrated broadband efficiencies of ∼91%, confirming the outstanding performance of this technology.


Photonic Lanterns as Wavefront Sensors

S. G. Leon-Saval,  Technical Digest Series (Optica Publishing Group, 2022), paper Th1E.1

Photonic lanterns are low-loss mode convertors easily integrated with optical fiber technologies. We present the proof of concept of a focal plane low-order wavefront sensor based on a 19-core multicore photonic lantern and deep learning.