Photonic generation of Terahertz (THz) carriers displays high potential for THz communications with a large tunable range and high modulation bandwidth. While many photonics-based THz generations have recently been demonstrated with discrete bulky components, their practical applications are significantly hindered by the large footprint and high energy consumption. Herein, we present an injection-locked heterodyne source based on generic foundry-fabricated photonic integrated circuits (PIC) attached to a uni-traveling carrier photodiode generating high-purity THz carriers. The generated THz carrier is tunable within the range of 0-1.4 THz, determined by the wavelength spacing between the two monolithically integrated distributed feedback (DFB) lasers. This scheme generates and transmits a 131 Gbits(-1) net rate signal over a 10.7-m distance with -24 dBm emitted power at 0.4 THz. This monolithic dual-DFB PIC-based THz generation approach is a significant step towards fully integrated, cost-effective, and energy-efficient THz transmitters. A photonic Terahertz source based on injection-locking an integrated dual-laser chip generates and transmits a 131 Gbps THz signal over 10.7-m distance, showing great potential towards fully integrated and energy-efficient THz transmitters for 6G.

Quantum key distribution (QKD) networks are potential to be widely deployed in the immediate future to provide long-term security for data communications. Given the high price and complexity, multi-tenancy has become a cost-effective pattern for QKD network operations. In this work, we concentrate on addressing the online multi-tenant provisioning (On-MTP) problem for QKD networks, where multiple tenant requests (TRs) arrive dynamically. On-MTP involves scheduling multiple TRs and assigning non-reusable secret keys derived from a QKD network to multiple TRs, where each TR can be regarded as a high-security-demand organization with the dedicated secret-key demand. The quantum key pools (QKPs) are constructed over QKD network infrastructure to improve management efficiency for secret keys. We model the secret-key resources for QKPs and the secret-key demands of TRs using distinct images. To realize efficient On-MTP, we perform a comparative study of heuristics and reinforcement learning (RL) based On-MTP solutions, where three heuristics (i.e., random, fit, and best-fit based On-MTP algorithms) are presented and a RL framework is introduced to realize automatic training of an On-MTP algorithm. The comparative results indicate that with sufficient training iterations the RL-based On-MTP algorithm significantly outperforms the presented heuristics in terms of tenant-request blocking probability and secret-key resource utilization.

We show 100 Gbaud PAM4 400 meters link with performance below the 7% HD-FEC limit of 5x10-3 without optical amplification and post-equalization. We also show 300 Gbps PAM8 line rate transmission over 400 meters of SSMF in C-band. 

107.1 and 93.9-Gbps net-rate (gross-rate 133.9 and 101.3-Gbps) OFDM transmission on a 408-GHz carrier frequency is experimentally demonstrated over a joint fibre-wireless link, 51-km single-mode fibre and 10.7-m free-space, with bit-error-rates below the 20% soft- and 7% hard-decision FEC thresholds of 2.7×10-2 and 3.8×10-3, respectively.

We report on an ON OFF keying intensity-modulation and direct-detection C-band optical transceiver capable of addressing all datacenter interconnect environments at well beyond 100 Gbaud. For this, the transmitter makes the use of two key InP technologies: a 2:1 double heterojunction bipolar transistor selector multiplexer and a monolithically integrated distributed feedback laser traveling-wave electro-absorption modulator, both exceeding 100-GHz of 3-dB analog bandwidth. A preamplified 110-Gaz PIN photodiode prior to a 100-CHs analog-to-digital converter complete the ultrahigh bandwidth transceiver module; the device under study. In the experimental work, which discriminates between intra- and inter-data center scenarios (dispersion unmanaged 120, 560, and 960 m; and dispersion-managed 10 and 80 km of standard single-mode fiber), we evaluate the bit-error rate evolution against the received optical power at 140, 180, and 204 Gbaud ON OFF keying for different equalization configurations (adaptive linear filter with and without the help of short-memory sequence estimation) and forward error correction schemes (hard-decision codes with 7% and 20% overhead); drawing conclusions from the observed system-level limitations of the respective environments at this ultrahigh baudrate, as well as from the operation margins and sensitivity metrics. From the demonstration, we highlight three results: successful operation with >6-dB sensitivity margin below the 7% error-correction at 140 Gbaud over the entire 100 m-80 km range with only linear feed-forward equalization. Then, the transmission of a 180-Gbaud ON OFF keying carrier over 80 km considering 20% error-correction overhead. Finally, a 10-km communication at 204 (Maud ON OFF keying with up to 6 dB sensitivity margin, and regular 7% overhead error-correction.

We demonstrate 50-Gb/s DMT signal transmission over 20-km SMF by using a 10G-class 1.55-mu m DML without optical dispersion compensation. Injection locking technique is introduced, which doubles system bandwidth and greatly suppresses DML chirp.

This paper summarizes recent research on 5G transport networks addressing challenges on capacity, service migration and techno-economics that are brought by 5G new attributes, e.g., cloud radio access networks, diverse usage scenarios and heterogeneous deployments.

A point-wise reinforcement learning (PWRL) algorithm is proposed for a multi-detector based visible light positioning system. Experimental results demonstrate that the average positioning error is reduced up to 70% by employing the proposed PWRL.

A point-wise reinforcement learning (PWRL) algorithm is proposed for a multi-detector based visible light positioning system. Experimental results demonstrate that the average positioning error is reduced up to 70% by employing the proposed PWRL. 

All parts of an IM/DD system are being stretched to the limit as the single lane data rate approaches 200 Gbps and beyond. We report the recent developments on the key enablers conquering this target.