Physics-informed modeling of photonic lantern collection gain and diversity in free-space optical reception
Results in Optics, cilt.25, 2026 (ESCI, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 25
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.rio.2026.101173
- Dergi Adı: Results in Optics
- Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI), Scopus
- Anahtar Kelimeler: Coupling efficiency, Free-space optical communication, Optical diversity reception, Photonic lantern, Physics-informed modeling, Speckle
- Abdullah Gül Üniversitesi Adresli: Evet
Özet
Photonic lanterns interface distorted free-space optical fields with coherent single-mode receivers by converting a multimode field into multiple single-mode branches that can be coherently combined. Recent measurements report a pronounced near-field collection gain for photonic-lantern-assisted reception under collimated coupling, yet the physical mechanism and its impact on statistical reliability require clarification. Here we develop a physics-informed numerical model that captures (i) near-field growth of the coupled spot relative to the single-mode fiber mode, together with residual wavefront curvature, (ii) lantern transition loss driven by an explicitly defined effective number of excited spatial modes, and (iii) distance-dependent correlation among lantern branches. The lantern is described by its physical parameters (19 ports, 50 μm multimode core, NA = 0.22, 1.3 dB insertion loss), and the transition loss follows from a mode-overflow argument with a single fitted coefficient. Calibrated to two experimentally reported reference points, the model reproduces a near-field collection gain of 7.9 dB at 0.5 m and near-unity gain in the far field (0.23 dB at 10 m). A mechanism-decomposition study shows that this gain originates almost entirely from spot-size mismatch of the collimated beam, which collapses single-mode coupling while the multimode aperture still collects efficiently; residual curvature contributes a few tenths of a decibel. All model components are verified against closed-form analytical results, and a concrete measurement protocol with falsifiable predictions is outlined for experimental validation. Under maximum-ratio combining, lanterns reduce deep-fade probability by orders of magnitude and compress fading about fivefold even when the average power gain vanishes.