Multi-functional electro-optic (EO) logic gates are promising core building blocks for future optical programmable logic arrays (PLAs) and field-programmable gate arrays (FPGAs). However, most existing multi-functional EO logic schemes suffer from three critical bottlenecks: cumbersome multi-parameter logic switching, limited operating-point tunability, and poor cross platform universality, which severely hinder their practical deployment. To address these challenges, we propose a unified vector cascading model that enables fast single-parameter logic switching and high operating-point tunability across two typical multi-functional EO logic platforms, namely the bias-controlled (BC) and polarization-controlled (PC) platforms. Represented by a newly constructed constellation diagram, the model unifies the input logic vectors for all Boolean operations and supports continuous operating-point tuning. We further derive a mathematical transformation between the BC and PC platforms, establishing a theoretical foundation for cross-platform universality. Both simulations and experiments validate the correctness of the proposed model and the derived transformation, showing that the two platforms achieve consistent logic performance with an extinction ratio difference below 0.001 dB in simulation and 0.1 dB in experiment. By overcoming the three key limitations, this work provides a unified, scalable, and standardized solution for high-performance optical PLAs and FPGAs.
Fiber-based dual-comb interferometry enables high resolution optical metrology and Light Detection and Ranging (LiDAR) without mechanical scanning. However, practical deployment of high-precision LiDAR remains hindered by the complexity of dual-laser active stabilization, slow acquisition speeds, and environmental vulnerability of conventional point scanning architectures. To address these bottlenecks, we demonstrate a stabilization-free, single-shot line-scan three dimensional (3D) ranging system configured as a compact LiDAR prototype. Driven by a dual-wavelength single-cavity dual-comb fiber laser (SCDCFL), it leverages passive common-mode noise suppression to maintain mutual coherence. Unlike conventional time-of-flight (ToF) LiDAR, which is fundamentally constrained to millimeter-level precision, our approach integrates grating based spectral encoding with an amplitude-confidence-weighted phase extraction strategy algorithm. By extracting nanometric depth profiles from interference phases and mapping them onto high-fidelity amplitude distributions, the system achieves optimized 3D imaging without requiring temporal signal averaging. The system achieves 27 mHz passive repetition-rate difference stability and 546 μs single-shot acquisition. It demonstrates ∼70 μm lateral resolution and resolves sub micrometer features, including a ∼126 nm chromium film, under ∼2 μW echo power. This work bridges laboratory metrology and field-deployable photonic instrumentation, enabling high-speed, high-precision 3D LiDAR for industrial inspection and autonomous platforms.
A widely tunable optoelectronic oscillator (OEO) incorporating a microring-resonator (MRR)-based microwave photonic bandpass filter (MPBF) and a multi-passband sapphire resonator is proposed and experimentally demonstrated. The MRR-based MPBF realizes continuous broadband frequency tuning via adjusting the spectral detuning between the laser carrier and the MRR resonant wavelength. Meanwhile, the sapphire filter provides a series of ultra-narrow discrete passbands to accomplish high-selectivity mode selection. Once the passband of the MPBF overlaps one targeted resonant peak of the sapphire filter, the round-trip loop gain peaks at the coincident frequency and triggers single-mode microwave oscillation at the target frequency. In the proposed configuration, the MRR-based MPBF features a full width at half maximum (FWHM) bandwidth of 43.53 MHz and a tuning capability up to 20 GHz, whereas the sapphire filter yields multiple available resonant passbands across 4–20 GHz with individual bandwidths varying from hundreds of kilohertz to several megahertz. Such bandwidth discrepancy originates from frequency-dependent transmission loss and varied external coupling conditions. Experimental measurements achieve tunable oscillation from 4.52 to 19.72 GHz with adequate loop gain. The resulting microwave signal attains a single-band phase noise of −122.3 dBc/Hz at a 10-kHz offset. This hybrid filtering configuration provides a feasible and effective solution for developing low-phase-noise OEOs with broadband frequency tunability.
In this paper, we propose and implement a novel optical fiber composite overhead ground wires (OPGW) architecture integrating hollow-core anti-resonant fiber (HC-ARF) and G.652.D single mode fiber to achieve both high-speed optical communication and lightning sensing. Experimental results show that, under simulated lightning conditions with current intensity lower than actual strikes, HC-ARF supports 100G coherent signals with exceptional lightning immunity, reducing the state of polarization (SOP) variation rate by two orders of magnitude compared to G.652.D fiber. When paired with HC-ARF, the latest 100G “Pine Tree” series optical transport network (OTN) (a power-tailored 100G coherent optical transport platform developed by FiberHome, integrated with self-developed high-performance SOP tracking coherent modules, optimized for ultrafast polarization fluctuations induced by OPGW lightning strikes) nearly eliminates lightning-induced interference, while the earlier-generation FONST 5000 OTN achieves 62.9% interference suppression under the same configuration. To enable lightning localization, a simple detection system based on G.652.D fiber and polarizing beam splitter (PBS) is also implemented. This architecture enhances lightning resilience while advancing sensing–communication integration for next-generation smart grid applications.
Subsea fibre-optic cables form a critical component of global communication infrastructure but remain vulnerable to damage from maritime activities such as bottom-trawling and anchor drags. Reliable identification of physical contact events is essential for effective cable integrity monitoring, requiring robust discrimination between potentially damaging interactions and benign activity. This paper presents field observations of bottom-trawler-induced cable interactions obtained from a live subsea communication link in the North Sea. An 880 km cable was monitored using State-of-Polarisation (SoP) sensing over its full length, complemented by Automatic Identification System (AIS) vessel-tracking data and Distributed Acoustic Sensing (DAS) trawler-detection algorithms over the first 120 km. The results show that SoP measurements exhibit consistent signatures associated with physical contact events. In contrast, although DAS enables detection and localisation of approaching trawls, strong perturbations produce similar responses for physical contact and non-contact trawl crossing events, limiting reliable discrimination. These findings demonstrate that SoP sensing, particularly when combined with external data sources such as AIS, provides a practical and scalable method for subsea cable-integrity monitoring, enabling reliable identification of potentially damaging interactions with the cable.
