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Fiber-to-chip couplers play a crucial role in interfacing on-chip photonic circuits with other optical systems or off-chip devices. Downsizing the couplers via topology optimization addresses the demand for high-density integration and…

This paper presents an innovative set of tools to support a methodology for the multichannel interpolation (MCI) of a discrete signal. It is shown that a bandlimited signal $f$ can be exactly reconstructed from finite samples of $g_k$…

Information Theory · Computer Science 2019-04-12 Dong Cheng , Kit Ian Kou

There is considerable interest in the combined use of millimeter-wave (mmwave) frequencies and arrays of massive numbers of antennas (massive MIMO) for next-generation wireless communications systems. A symbiotic relationship exists between…

Information Theory · Computer Science 2017-12-19 Amine Mezghani , A. Lee Swindlehurst

Photonic Lanterns (PLs) are tapered waveguides that gradually transition from a multi-mode fiber geometry to a bundle of single-mode fibers (SMFs). They can efficiently couple multi-mode telescope light into a multi-mode fiber entrance at…

Instrumentation and Methods for Astrophysics · Physics 2024-02-14 Yoo Jung Kim , Michael P. Fitzgerald , Jonathan Lin , Steph Sallum , Yinzi Xin , Nemanja Jovanovic , Sergio Leon-Saval

Solid-state Spatial Light Modulators (SLMs) are fundamentally limited in their ability to achieve high spatial complexity and high temporal bandwidth simultaneously. High-speed, low-energy modulation requires sub-wavelength active mode…

Optics · Physics 2026-05-15 Virat Tara , Anna Wirth-Singh , Johannes E. Fröch , Arka Majumdar

Distributed microphone arrays composed of multiple subarrays enable blind source separation over a wide spatial area. Directly applying fast multichannel nonnegative matrix factorization (FastMNMF) to all subarrays can exploit observations…

Audio and Speech Processing · Electrical Eng. & Systems 2026-05-20 Hirotaka Nishikori , Nobutaka Ito , Kouei Yamaoka , Norihiro Takamune , Hiroshi Saruwatari

We propose to use slot micro/nano-fiber (SMNF) to enhance the second-harmonic generation based on surface dipole nonlinearity. The slot structure is simple and promising to manufacture with high accuracy and reliability by mature…

Optics · Physics 2015-06-12 Wei Luo , Fei Xu , Yan-qing Lu

Enabling efficient injection of light into single-mode fibers (SMFs) is a key requirement in realizing diffraction-limited astronomical spectroscopy on ground-based telescopes. SMF-fed spectrographs, facilitated by the use of adaptive…

Atmospheric turbulence severely limits the coupling of received optical wavefronts into single-mode fibers in satellite-to-ground free-space optical links. Spatial demultiplexing receivers address this challenge by distributing the incoming…

Optics · Physics 2026-03-20 Nicolas Barré

Optical fibres are the primary medium for optical signal transmission, and their guided modes provide a high-dimensional basis for modal-domain information encoding. However, conventional demultiplexing approaches typically convert fibre…

Optics · Physics 2026-05-29 Rundong Fan , Yamin Zheng , Pei Li , Xixiao Cao , Haoyang Wu , Zheng Cai , Lei Huang

We report the spatial beam self-cleaning in bi-tapered conventional multimode fibers (MMFs) with different tapered lengths. Through the introduction of the bi-tapered structure in MMFs, the input beam with poor beam quality from a…

In this paper, we explore the integration of low-power, low-cost stacked intelligent metasurfaces (SIM) into cell-free (CF) massive multiple-input multiple-output (mMIMO) systems to enhance access point (AP) capabilities and address high…

Information Theory · Computer Science 2024-09-20 Enyu Shi , Jiayi Zhang , Yiyang Zhu , Jiancheng An , Chau Yuen , Bo Ai

High-speed optical wireless communication can address the exponential growth in data traffic. Adaptive beamforming customized for the target location is crucial, but existing solutions such as liquidcrystal spatial light modulators and…

Networking and Internet Architecture · Computer Science 2023-04-27 Chao Li , Yiwen Zhang , Xinda Yan , Yuzhe Wang , Xuebing Zhang , Jian Cui , Lei Zhu , Juhao Li , Zilun Li , Shaohua Yu , Zizheng Cao , A. M. J. Koonen , Chia Wei Hsu

In this paper, we consider a two-hop one-way relay network for multigroup multicast transmission between long-distance users, in which the relay is equipped with multiple antennas, while the transmitters and receivers are all with a single…

Information Theory · Computer Science 2016-03-18 Sissi Xiaoxiao Wu , Qiang Li , Anthony Man-Cho So , Wing-Kin Ma

Super-resolution microscopy normally requiring complex and cumbersome optics is not applicable for in situ imaging through a narrow channel. Here, we demonstrate single hair-thin multimode fiber (MMF) endoscope (less than 250 ${\mu}m$) for…

We develop an improved phase calibration method of a reflective spatial light modulator (SLM) using interferometry by employing novel phase masks. We generate the optimised phase masks by using Iterative Fourier Transform Algorithm (IFTA)…

Optics · Physics 2022-04-26 Amar Deo Chandra , Ayan Banerjee

We present a theoretical and experimental investigation of the emission characteristics and the flux of photon pairs generated by spontaneous parametric downconversion in quasi-phase matched bulk crystals for the use in quantum…

Quantum Physics · Physics 2007-05-23 Daniel Ljunggren , Maria Tengner

We consider a practical cell-free massive multiple-input-multiple-output (MIMO) system with multi-antenna access points (APs) and spatially correlated Rician fading channels. The significant phase-shift of the line-of-sight component…

Information Theory · Computer Science 2021-10-13 Zhe Wang , Jiayi Zhang , Emil Björnson , Bo Ai

Many quantum computation and communication schemes require, or would significantly benefit from, true sources of single photon on-demand (SPOD). Unfortunately, such sources do not exist. It is becoming increasingly clear that coupling…

Quantum Physics · Physics 2009-11-10 Stefania Castelletto , I. P. Degiovanni , Michael Ware , Alan Migdall

We report on the development of a compact (volume $\approx$ 100\:cm$^3$), multimode diffraction-limited Raman spectrograph and probe designed to be compact as possible. The spectrograph uses `off the shelf' optics, a custom 3D-printed…

Instrumentation and Detectors · Physics 2020-03-04 Christopher H. Betters , Joss Bland-Hawthorn , Salah Sukkarieh , Itandehui Gris-Sanchez , Sergio G. Leon-Saval