2020/07/14 by Szu-Yu Lee, Vicente J. Parot, Brett E. Bouma +1
Engineering · Physics and Astronomy · #Multi-mode optical fiber #Optical fiber #Orbital Angular Momentum in Optics #Photonic Crystal and Fiber Optics #Photonics #Polarization (electrochemistry) #Random lasers and scattering media #Reciprocal #Reciprocity (cultural anthropology) #Symmetry (geometry) #Transmission (telecommunications) #physics.optics
paper · pdf · doi:10.1063/5.0021285
published as APL Photonics 5(10), 2020 · 11 pages, 6 figures, under review
arxiv created 2020/07/14 · openalex created_date 2020/07/23 · openalex publication_date 2020/10/01 · arxiv updated 2020/10/08 · openalex updated_date 2026/08/05
Reciprocity is a fundamental principle of wave physics and directly relates to the symmetry in the transmission through a system when interchanging the input and output. The coherent transmission matrix (TM) is a convenient method to characterize wave transmission through general media. Here, we demonstrate the optical reciprocal nature of complex media by exploring their TM properties. We measured phase-corrected TMs of forward and round-trip propagation in a single polarization state through a looped 1 m-long step-index optical multimode fiber (MMF) to experimentally verify a transpose relationship between the forward and backward transmission. This symmetry impedes straightforward MMF calibration from proximal measurements of the round-trip TM. Furthermore, we show how focusing through the MMF with digital optical phase conjugation is compromised by system loss since time reversibility relies on power conservation. These insights may inform the development of new imaging techniques through complex media and coherent control of waves in photonic systems.