Abstracts
STREAM 6: Telecommunications Wednesday 13:30 -15:00
STREAM 7: Photonic Components Wednesday 15:30 -17:00
Session Chair: Mingming Tan, Research Fellow, Aston Institute of Photonic Technologies, Aston University
Session Chair: SweZin Oo, Design Engineer & Technical Lead, Chip R&D department, Lumentum
Scalable Optical Access Architectures in 6G Front-Haul Alexandros Stavdas OpenLight Comm Ltd The role of fiber optic connectivity in access is
TILBA-ATMO: Enhancing Leo-To-Ground Downloads with 45-mode Turbulence Mitigation Jean Menguy, Cailabs
indispensable to support the emerging 6G applications and services. This assertion is supported by a number of techno-economic factors, such as the fact that there are multiple 6G functional splits available with dissimilar transportation line-rate and processing trade-offs, while
The rapid proliferation of Low Earth Orbit (LEO) satellite networks and the subsequent requirement for higher debit rates necessitates the development of efficient high-throughput communication technologies. This can be achieved using free-space optical (FSO)
the higher the RF bandwidths in FR2 deployments, the shorter the distance between small cells. In a landscape where the connectivity technologies are converging, there are many interdependent issues that must be resolved via co-design, ranging from the eventual small-cell densification to the possibility of fiber exhaustion in the trunk and distribution segments. In this work, we present scalable optical access architectures, and we assess how these can accommodate different 6G functional splits. Moreover, we present the results of a network dimensioning studies, and we quantify how these architectures address the challenges associated with 6G small cell deployments. Co-authored by: Alexandros Stavdas, Evangelos Kosmatos, Christos Matrakidis, and Ian Cooper; OpenLightComm Ltd. Advanced Characterization of Optical Modulators and Coherent Receivers for Multi-Band Transmission Systems Beyond C- and L-Band Robert Emmerich, HHI We present a comprehensive review of the components for prototype development aimed at efficient and sustainable capacity enhancement of already deployed single-mode fibre links. Our analysis includes measurements of individual components while focusing on their key performance indicators as a function of wavelength. Key findings of this investigation at the transmitter end include the identification of LiNbO3 and TFLN modulators as promising candidates for these systems, while InP modulators suffer from strong and undesirable wavelength dependencies. On the receiver side, discrete coherent receivers based on free-space technologies enable operation over a range of 200 nm, from E- to U-band. With additional components such as lasers, filters, wavelength-selective switches, and amplifiers now readily accessible, this will further drive research into multi-band systems. performance of currently available optical dual- polarization I/Q modulators and dual-polarization coherent receivers for multi-band transmission systems. Our evaluation covers various implementations of these technologies, facilitating the selection of
communication, allowing up to 100s Gbps. FSO downlinks are limited by atmospheric turbulences which strongly deteriorate debit rates, forbidding the use of fast detectors, fiber components and modulation schemes such as EDFAs and coherent modulation/ detection. Turbulence mitigation is therefore compulsory to enable high throughput in LEO-to-ground FSO applications. Cailabs’s approach focuses on the use of its core technology: Multi-Plane Light Conversion (MPLC). MPLC allows for demultiplexing of any incoming turbulent beam into a set of single-mode fibers (SMF) followed by an active optical recombining stage. By dynamically adjusting phase shifters of the recombining stage, one can ensure that a constructive interference is generated, thus merging the demultiplexed turbulent beam into a single SMF. Earlier results demonstrated the use of an 8-mode version of TILBA-ATMO for low turbulence (D/r0 < 7) and its compatibility with high data rates modulation schemes (up to 100 Gbps DP-QPSK). Optical Ground Stations (OGS) will be equipped with large telescopes (D> 40 cm) and therefore require mitigation of stronger turbulences (D/r0 >10), which leads to the need of higher spatial modes for collection and recombining. Here we demonstrate the use of a TILBA-ATMO system, based on a 45 Hermite-Gaussian (HG) modes MPLC, for turbulence mitigation in more realistic conditions with D/ r0 > 10 and high turbulence speeds. Experimental results of the system will be showcased for different turbulence conditions and performed in a variety of environments, from lab tests to outdoor tests.
CMOS-compatible process for fabricating high speed moduators in BTO Steven Tan, Rapid Photonics BB
Rapid Photonics is a startup company based in Amsterdam the Netherlands. It’s our mission to bring thin film Barium titanate (BTO) as a next-generation material for ultra-high-speed modulators in photonic integrated circuits (PICs) to the telecom and datacom market.
End-to-End Learning based Probabilistic Constellation Shaping in High-Capacity Optical Fibre Communication Systems Tianhua Xu, University of Warwick
BTO PIC modulators have been demonstrated with remarkable performance in terms of speed and energy efficiency. However, such BTO PIC modulators have not been used in optical transceivers due to lack of scalability of production. We have developed a BTO PIC technology that is scalable and highly suited for volume production. Our patented technology is 100% silicon compatible and delivers a high yield. We have inhouse capacity to fabricate prototype PICs with a lead-time of 4 weeks and at affordable cost. Volume production can be delivered by any CMOS fab. We are currently developing reference designs for a 100GHz modulator and ultra-narrow linewidth tunable laser with fast tuning speed.
The end-to-end learning approach has shown strong potential in achieving robust constellation shaping for optical fibre communication systems. However, current end-to-end probabilistic constellation shaping (PCS) methods, which utilise binary cross-entropy combined with source entropy to estimate generalised mutual
information (GMI) as the loss function, fall short in fully realising the shaping gain. This limitation arises because, in PCS, both binary cross-entropy and source entropy are influenced by shifts in the probability distribution of square QAM constellation points, leading to a learned distribution that remains close to uniform. In response, this work introduces a novel end-to-end based PCS approach that incorporates a modified loss function, which includes an adaptive weight factor to adjust the impact of binary cross-entropy and source entropy on GMI dynamically. The GMI optimised with the proposed PCS aligns closely with the Maxwell-Boltzmann distribution for AWGN channels, for high-capacity optical fibre communication systems.
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