A 256 GSa/s SiGe 1-to-4 ADeMUX chip is shown to enable ultrahigh-speed IM/DD by demultiplexing received ultrabroadband optical signal for sampling using ADCs with only 33 GHz bandwidth. First ADeMUX-based reception of 200 GBd PAM-4 and 176 GBd PAM-8 signals is achieved, yielding record net bitrate of 464.1 Gbit/s.

We demonstrate a dynamic multi-agent system distributed over 811-km optical transport networks for cross-domain orchestration and monitoring. By selecting optimal agents based on instantaneous conditions, the system achieves greater stability and 2.9× lower latency.

We measure the impulse response of a 10-km support-tube hollow core fiber (ST-HCF) showing the effects of higher-order mode propagation and multi-path interference. A linear split-step simulation validates both the measurement and model.

We demonstrate OESCL-band same-wavelength bi-directional transmission over 60 km HCF with 42.5 THz bandwidth, achieving GMIs comparable with the highest unidirectional SMF data-rates in both directions, with an aggregate of 423.7 + 426.5 Tb/s.

We investigate optical interconnect latency effects on large language model inference under various parallelism strategies. We experimentally demonstrate distributed LLM inference over multi-core fiber for highly parallel optical interconnect in AI systems.

We experimentally study simplified multiple-input multiple-output (MIMO) processing schemes to support high-capacity space division multiplexed transmission over multiple multi-mode fibers (MMFs) with different mode counts. We exploit the mode selectivity of multi-mode fibers (MMFs) and components to implement a mode group (MG)-based transmission, and MIMO processing. We evaluate various transmission scenarios involving both a 15-mode MMF, and a 6-mode MMF, using different combinations of adjacent and non-adjacent MGs. For signal detection and recovery, we employ simplified MIMO processing approaches to reduce the complexity of the digital signal processing (DSP). We show enhanced flexibility compared to our recent work, demonstrating data recovery even in transmission scenarios with propagation of adjacent MGs, and high uncompensated inter-MG crosstalk. We achieve throughput from 70 Tb/s to 165 Tb/s by transmitting polarization-multiplexed 16-QAM signals across the C-band. We show that the transmission penalty due to uncompensated inter-MG crosstalk is limited to 1.1 bit/symbol. We also show a significant DSP simplification in all considered scenarios, with a total MIMO tap reduction between 52$\%$ and 66$\%$ compared to conventional full-MIMO processing. Our results demonstrate the capability of simplified MIMO schemes to support high-capacity transmission over heterogeneous MMFs in SDM networks.

The exponential growth of global data traffic driven by artificial intelligence and cloud computing necessitates cost-efficient, ultrahigh-capacity optical interconnects. Integrated photonic interconnect offers a promising solution but faces critical bottlenecks: integrated coherent receivers require local oscillator (LO) lasers, resulting in material incompatibility and cost challenges for monolithic integration, while integrated self-coherent schemes fundamentally suffer from nonlinear distortions induced by the nonlinear beating process between signal inputs during optical-to-electrical mapping, which limits both capacity and spectral efficiency. Here, we present an integrated LO-free homodyne detection scheme with superior linearity enabled by a micro-ring filter. The Si3N4 micro-ring resonator effectively filters out the optical carrier for homodyne detection, saving the LO in coherent receivers and eliminating the second-order nonlinear distortions commonly encountered in self-coherent schemes. Our fabricated monolithically integrated silicon photonic receiver enables single-polarization 600-Gb/s 16-ary quadrature amplitude modulated orthogonal frequency division multiplexing signal transmission over an 80-km fiber, achieving a net 480-Gb/s per polarization. This represents an 86% improvement over previous integrated self-coherent detection records and matches that of state-of-the-art integrated coherent systems. Multichannel validation across the C band further confirms the dense wavelength-division multiplexing compatibility. This work provides an Optical communication, dense wavelength division multiplexing, direct detection, integrated photonic interconnects, silicon photonicsscalable and cost-effective solution essential for future 1.6 Tb/s per lane optical interconnects.

We demonstrate continuous distributed acoustic sensing over a 4400km long undersea cable. Bi-directional operation improves the strain signal-to-noise rate by >20dB, enabling 88000 50-m-spaced measurement points at a nominal telecom launch power.

We propose using large language models (LLMs) to optimize fiber design simulations and enhance automation. Our results demonstrate that LLMs can efficiently design multimode fibers with reduced mode coupling between mode groups.

We present the design and characterization of co-planar stripline Mach-Zehnder modulators on an InP platform. The co-planar design exhibited 50 Ω impedance with velocity-matched optical and electrical signals. We investigated devices with a range of design parameters to identify optimal configurations for high bandwidths (≈80 GHz) and state-of-the-art data transmission rates (320 Gbit/s). An equivalent circuit model that enables fast and holistic design space exploration is developed and experimentally verified. The model predicts ∼120 GHz bandwidth for optimized modulator dimensions.

We detect the recent M8.8 mega-earthquake in Eastern Russia, on a 4400km long active telecom cable in the Pacific Ocean. The resolution achieved 100m represents the highest spatial resolution, the largest number of ocean-bottom sensors, and the first fiber-optic deep-ocean observation of a tsunami wave.

A new scheme for spatially resolved measurement of mode dispersion, modal birefringence and differential chromatic dispersion in few-mode fibers is presented and experimentally validated on a weakly-coupled, 4-mode-group fiber. The method relies on spectral correlation analysis between fiber's coherent Rayleigh backscattering traces generated by each of the supported mode groups, measured through optical frequency domain reflectometry. The presented technique provides a viable and effective way to measure modal and chromatic dispersion properties between arbitrary pairs of modes of the probed fiber, providing sub-picosecond delay resolution and centimeter-scale spatial resolution.

Data rates in optical networks have grown exponentially in recent decades and are expected to grow beyond the fundamental limits of current standard single-mode fiber networks. As such, novel transmission technologies are required to sustain this growth, and space-division multiplexing provides the most promising candidate to scale the capacity of optical networks in a way that is also cost-effective. For fiber fabrication and deployment, it is highly beneficial to use fibers with a standard cladding diameter. Here we demonstrate petabit-per-second-class data transmission using a space-division multiplexing fiber that approaches the limits of spatial multiplexing whilst minimizing the required signal processing complexity. This is done by designing and fabricating a low-loss 19-core multi-core fiber with randomly-coupled cores, a standard cladding diameter, and supporting a wideband wavelength-division multiplexed signal. The resulting data rate of 1.7 petabit/s is the highest reported amongst standard cladding diameter multi-core fibers and is approximately more than an order of magnitude higher than is supported by currently deployed single-mode fibers, paving the way for next-generation ultra-fast optical transmission networks.

We analyze the power conversion efficiency of cladding-pumped multi-core erbium-doped fiber amplifiers, showcasing their ability to outperform core-pumped counterparts by harnessing the superior electro-optical efficiency of multimode pump diodes. (c) 2025 The Author(s)

We propose direct pumping of multicore (MC) erbium-doped fiber amplifiers (EDFAs) using a pump diode array chip with multiplane light conversion. Experiments demonstrate compact fan-in/fan-out-free 4/7-core MC EDFAs, and a single-mode (SM) EDFA array via pump-division multiplexing, achieving SM EDFA-level efficiency while supporting scalable integration.

A novel packaged laser based on a SiN waveguide cavity is presented, which enables wide tunability (60 nm) while maintaining phase stability comparable with fixed frequency ultrastable sensing lasers. The laser enables long range full C-band OFDR characterization of a 280-km subsea span. (c) 2025 The Author(s)

We combine 6 doped-fiber amplifiers (O-(x2), E-, S-, C-, L-bands) with discrete Raman U-band amplifiers and distributed Raman-amplification to transmit in each of the low-loss transmission bands of a standard optical fiber. For transmission distances up to 100 km, we explore ultra-wideband transmission of up to 1505 x 25 GHz spaced channels covering the O-, E-, S-, C-, L- and U-bands from 1281.2 nm to 1649.9 nm. After describing the amplifier and spectrum flattening technology, we first characterize the transceiver in back-to-back configuration. Then, for 50 km transmission, we report a record aggregate transmission bandwidth of 37.6 THz with a record standard single-mode fiber transmission data-rate of 402.2 Tb/s, estimated from GMI, and 378.9 Tb/s after FEC decoding. 100 km transmission allows a 36.6 THz bandwidth with 339 Tb/s GMI estimated data-rate and 322.8 Tb/s decoded data-rate. These results show the potential of ultra-wideband transmission covering the low-loss window of silica fibers as well as the challenges of building such systems on longer fiber spans.

We evaluate the use of partial-MIMO demultiplexing using multi-mode fibers with 15 and 6 modes. We show effective signal recovery without the need for full-MIMO at the cost of throughput and evaluate the limits of the system. (c) 2025 The Authors

We use an ITU-T G.654.B/D compatible fiber to transmit 209, 3-mode, O-band signals, below the 1530 nm cut-off wavelength, and 706 single-mode, E/S/C/L-band signals, to reach a record throughput of 430.2 Tb/s (GMI)-398.6 Tb/s (decoded) with 30.1 THz bandwidth after 10 km. (c) 2025 The Author(s)