Showing papers by "Yuki Yoshida published in 2020"

A Phase-Retrieving Coherent Receiver Based on Two-Dimensional Photodetector Array

Abstract: To achieve an ultra-compact and flexible coherent transceiver solution, a carrier-less coherent detection technique using a two-dimensional (2-D) photodetector array (PDA) is proposed based on the idea of phase retrieval (PR). In the proposed PR-based coherent receiver, the optical phase information is digitally reconstructed from multiple intensity-only measurements acquired by arrayed photodetectors; neither local light sources, optical hybrids, nor spatial demultiplexers are needed. We develop a robust and low-complexity PR algorithm, which exploits prior knowledge on the optical modulation format, for the proposed PR receiver. As a proof-of-concept, the coherent detection of 10-Gbaud optical phase-modulated signals, including QPSK, 16-QAM, coherent optical OFDM, and polarization-multiplexed QPSK signals, using only a 2-D PDA is demonstrated experimentally.

Self-organized micro-light-emitting diode structure for high-speed solar-blind optical wireless communications

Abstract: The origin of the fast modulation characteristics of deep ultraviolet (DUV) AlGaN light-emitting diodes (LEDs) grown on AlN/sapphire templates with vicinal off-angles is reported by employing time-resolved electroluminescence (EL) and micro-imaging experiments. The LEDs have recently demonstrated Gbps-class optical wireless communication (OWC) under both room-lighting and direct-sun. The frequency response (f3dB) of the LED reached 184 MHz, which is far beyond expectations by considering the size of the LEDs. Since self-organized micro-LED structures with a low electric capacitance (C) are observed by the EL experiments, the compatibility of high efficiency and fast modulation nature of the AlGaN LEDs is explained. Our approach can overcome the dilemma, where micro-LEDs can be modulated fast but have low power, and therefore, the self-organized micro-LED structure is an ideal solution to realize practical DUV OWCs.

First Demonstration of Autonomous TSN-based Beyond-Best-Effort Networking for 5G NR Fronthauls and 1,000+ Massive IoT Traffic

Abstract: We propose and demonstrate a beyond-5G x-haul platform with autonomous time aware shaper and adaptive mobile fronthaul compression, which simultaneously accommodates real-time 5G NR-class fronthauls (2*29.49-Gbps CPRI-equivalent-rate) and 1,000+ massive IoT live backhaul traffic through a 10GbE interface while keeping $ end-to-end fronthaul latency.

Demodulation of Eigenvalue Modulated Signal Based on Eigenvalue-Domain Neural Network

Abstract: A demodulation scheme for an eigenvalue modulated signal based on an eigenvalue-domain neural network is demonstrated experimentally. Successful demodulation is demonstrated at 2.5 Gb/s over a transmission distance of up to 3,000 km.

Characterization of a Self-Organized Deep-Ultraviolet Micro-Light-Emitting Diode Structure for High-Speed Solar-Blind Optical Wireless Communications

Abstract: Time- and spatio-resolved electroluminescence spectroscopy was performed to characterize a self-organized micro-structure in the AlGaN LEDs, which have realized gigabit-class solar-blind optical wireless communication.

<500ns Latency Overhead Analog-to-Digital-Compression Radio-Over-Fiber (ADX-RoF) Transport of 16-Channel MIMO, 1024QAM Signals with 5G NR Bandwidth

Abstract: Real-time analog-to-digital-compression radio-over-fiber (ADX-RoF) transport with <500ns processing latency overhead is demonstrated by using a single-chip programmable radio platform. 16-channel 61.44MHz 1024QAM-OFDM signals of 5G NR-class is delivered with ∼4-Gb/s optical OOK interface, maintaining EVM<1.4%.

High Speed 2D-PDA FSO Receiver for High Optical Alignment Robustness with Space Diversity

Abstract: We present a free space optics receiver with high robustness for optical alignment using a large active area, high-speed 2D-PDA, and its demonstration of 40-Gbps (PAM4) signal detection using a space diversity technique in DSP.

On the Sample Complexity of Phase-Retrieval Receiver Based on 2-D Arrayed Photodetectors

Abstract: Sample complexity, or equivalently the required number of photodetectors, of a carrier-less phase-retrieving coherent receiver is investigated numerically based on the experimental data; it can achieve comparable complexity to conventional coherent receivers.

Up-to 292-Mbps Deep-UV Communication over a Diffuse-Line-of-Sight Link Based on Silicon Photo Multiplier Array

Abstract: Towards a Gbps-class outdoor mobile optical wireless communication (OWC), we experimentally investigate an up-to 292-Mbps diffuse-line-of-sight OWC in the solar-blind band based on an AIGaN-LED and a Silicon photo multiplier array under a typical indoor illumination condition.

Single-Pixel IQ Monitor via Computational Coherent Reception with Widely Linear Phase Retrieval

Abstract: For in-service and in-field monitoring of frequency-dependent IQ imbalance in optical IQ modulators, we propose a low-complexity IQ monitor using a single photodetector based on phase retrieval. The feasibility of the proposed single-pixel IQ monitor was demonstrated experimentally with a 63.25-Gbaud 16QAM signal.

2-D photodetector array for high-data-rate spatial sampling

Abstract: In this paper, we report on a newly developed 2D-PDA device, and its applications for carrier-less, phase retrieval coherent detection, and space diversity signal detection in free-space optical communications.

Artificial Neural Network-Based-Receiver for Eigenvalue-Modulated Signal in Presence of Optical CFO

Abstract: We demonstrate the demodulation of an eigenvalue-modulated signal combining an artificial neural network with a CFO compensation. The proposed demodulator achieves successful demodulation with power penalty < 1 dB in the presence of CFO within 1 GHz at 2.5 Gb/s in experiments.

High Temperature Operation of Quantum Dot Semiconductor Optical Amplifier for Uncooled 80 Gbps Data Transmission

Abstract: The amplification of 80 Gbps non-return to zero signal and error-free operation within the FEC limit were demonstrated in online data transmission measurements at over 60°C using quantum dot SOA.

Demonstration of Indoor 5G Fronthaul over Legacy Multimode Fiber Enabled by Real-time Analog-to-digital Compression (ADX)

Abstract: An analog-to-digital-compression radio-over-multimode-fiber (ADX-RoMMF) scheme is proposed and experimentally demonstrated for high-fidelity, cost-effective indoor 5G-and-beyond access. Real-time fronthauling of 16-channel MIMO, 5G NR-bandwidth 1024QAM signals verify more than 4-fold MMF reach extension compared with conventional scheme, while maintaining 500ns one-way ADX latency.

Generalization Performance of Artificial Neural Network Based-Demodulator for Eigenvalue Modulated Signal

Abstract: The generalization performance of an artificial neural network-based demodulator for an eigenvalue modulated signal is investigated. Successful demodulation for transmission distances from zero to 3,000 km and carrier frequency offset within 1 GHz is demonstrated.

Phase-Retrieving Coherent Reception and its Sample Complexity

Abstract: Low-complexity coherent receivers based on direct detection are revisited from the viewpoint of sample complexity, number of magnitude samples per symbol in phase retrieval (PR). Recent experimental results on the carrier-less PR receiver by using a 2-D photodetector array are also reported.