Optics letters最新文献

We present a method for resolving spatial mode overlaps in coupled microresonators based on Kerr and thermal cross-phase modulation. Through a pump-probe setup, we measure the experimental overlap in a three-ring resonator with good agreement with analytical theory. Our technique can be generalized for describing nonlinear interactions in more complex multi- and coupled-mode systems.

The difficulty of growing high-quality infrared-sensitive materials and their heterogeneous integration with silicon circuits has long been a key factor hindering the development of infrared detectors. In this work, we report a broadband infrared detector fabricated directly on an SOI substrate through arsenic doping. The optical absorption efficiency in the absorption region (AR) is greatly enhanced through a sophisticated photo-trapping structure design, leading to a significant improvement in quantum efficiency over the entire response range. The fabricated photo-trapping SOI:As detectors exhibit average enhancement of 346% for external quantum efficiency (EQE) and 696% for internal quantum efficiency (IQE) across the 7-22 μm range. The EQE and the IQE at the peak wavelength reach 20% and 40% with an extremely thin AR (~100 nm). This CMOS-compatible hybrid architecture provides a promising pathway toward high-performance and large-scale monolithic infrared detector arrays.

Multi-core fibers have emerged as a promising solution for high-power fiber laser systems, which allow for the simultaneous mitigation of thermal and nonlinear effects through core-count scaling. This makes them highly attractive for high-average-power applications. However, there has been no demonstration of a multi-kilowatt, multi-core fiber laser system to date. In this work, we present a Yb-doped, multi-core fiber laser system, delivering up to 3.2 kW of average power (over all cores) with excellent short- and long-term stability. The system exhibited a slope efficiency with respect to launched power of 86.3%, and the output power was limited only by the available pump power.

Artificial photoelectric synaptic devices have exhibited remarkable advantages of low power consumption and high speed for neuromorphic computing. By integrating photodetection and memory functions, these devices offer a promising framework to resolve the limitations of von Neumann architectures. Herein, transparent photoelectric synaptic devices were fabricated based on amorphous InHfZnO/Ga₂O₃ heterojunction by plasma-enhanced atomic layer deposition. The heterojunction was comprehensively characterized with various techniques. For the fabricated devices, critical synaptic characteristics, including short-term plasticity (STP), paired-pulse facilitation (PPF), and long-term plasticity (LTP), were systematically characterized and evaluated under various optical conditions and temperatures. Based on temperature-dependent performance variations, the temperature-tunable mechanism of the devices was analyzed in terms of oxygen vacancy concentration evolution.

We demonstrate a high-power InGaAs/GaAs quantum well (QW) gain chip that achieves a suppressed linewidth enhancement factor (α-factor) by utilizing the second conduction subband (E2) transition. The low α-factor is intrinsically enabled by operating the device on the E2 transition, while high-power single-mode operation is ensured by an asymmetric epitaxial waveguide and a J-shaped ridge structure. The device exhibits a gain peak shift from 1050 nm (first conduction subband (E1) transition) to 990 nm (E2 transition) at high current injection, achieving a fundamental transverse-mode output of 180.01 mW, with α-factor suppressed. Compared to the E1 transition, the E2 transition offers a sixfold reduction in α-factor and demonstrates markedly lower sensitivity to carrier fluctuations. Additionally, the E2 transition yields a higher gain than E1, enhancing the potential for high-power scaling. This work validates E2-transition engineering as an effective strategy for high-performance narrow-linewidth light sources.

This Letter investigates the phase noise estimation (PNE) problem in probabilistic shaping (PS) dual-polarization continuous spectrum nonlinear frequency division multiplexing (DP-CS-NFDM) systems. Firstly, a rigorous phase noise model in the nonlinear Fourier domain establishes the structure of intra-burst impairment, consisting of a common phase rotation on the ideal nonlinear Fourier coefficient plus an additive signal-coupled perturbation. This finding motivates a low-complexity per-burst PNE scheme. Secondly, we propose a QPSK-partitioning and decision-aided (QP-DA) scheme, which integrates QPSK-partitioning with a decision-aided mechanism to counteract the performance degradation of conventional PNE induced by PS. Finally, the experimental validations on a 40 GHz PS DP-CS-NFDM system demonstrate that the proposed QP-DA scheme achieves a 187-km extension in transmission reach and a 475-kHz improvement in laser linewidth tolerance over the blind phase search (BPS) benchmark, yielding a computational complexity of merely 8.4% relative to BPS.

This Letter proposes a physics-embedded Gaussian process regression (GPR), which is simultaneously high-fidelity and reliability-aware, for extrapolating the radar cross section (RCS) of a target under geometric scaling. Distinct from alternative RCS extrapolation models that operate in the RCS domain, we establish the model in the scattered electric-field domain rooted in the nature of the coherent superposition of electromagnetic waves. By designing a composite kernel that integrates a degree-2 generalized polynomial for scaling laws and a spectral mixture (SM) kernel for interference effects, we explicitly encode these physical priors into the GPR framework. Validated on a simple warhead model and the complex SLICY model, the proposed GPR reduces the root-mean-square extrapolation error by up to 91.5% compared to other alternative models, while providing physics-grounded uncertainty quantification for reliability assessment.

We demonstrate a novel, to the best of our knowledge, cladding-localized Rayleigh-scattering-enhanced (cl-RSE) fiber that provides broadband, low-loss self-injection feedback. Through system optimization, the reel-to-reel femtosecond-laser inscription system limits fiber jitter to <5 µm during meter-scale processing. The resulting 2-m cl-RSE fiber exhibits 10-40 dB random scattering enhancement at each point, with an overall 22 dB reflection increase and only 0.7 dB total loss. Serving as a passive external cavity for a DBR fiber laser, the cl-RSE fiber compresses the linewidth by half. Its feedback remains stable under temperature fluctuations and dynamic strain, demonstrating the practicality of cl-RSE fiber as a robust, alignment-free device for linewidth narrowing.

We present a universal framework for intra-cavity phase retrieval in nondegenerate laser systems, employing a single lossless pure-phase hologram to achieve on-demand spatial mode generation at the source. By integrating mode-reproducing dynamics into a canonical extra-cavity phase retrieval pipeline, joint optimization is enabled for the holographic patterns and loose-state phase distribution on the output coupler. Experimental results showcase the generation of arbitrary intensity profiles, including square flat-top, "X"-shaped, and club-shaped beams. Experimental analysis confirms that precise mode discrimination is achieved via distinct diffractive losses during free-space propagation, rather than local losses imposed on the hologram. Additionally, counter-propagating tailored beams are realized, and interference experiments validate their coherence.

The non-deterministic nature of photon sources poses a fundamental challenge to scaling single-photon quantum processors. While multiplexing in space, time, and frequency can enhance heralding efficiency, key bottlenecks remain in the efficiency of the on-chip resource unit and the speed of the external control system. Here, we demonstrate a high-count-rate, spatially multiplexed single-photon source on a silicon chip. By implementing a bidirectional pumping scheme, our architecture halves the number of required photon sources, creating a compact, optimized unit for future large-scale multiplexing sources. In addition, we implement a control system based on a Random-Access Memory First-In-First-Out module to improve the count rate limitation. Experimental results demonstrate a coincidence count rate gain of 1.67 under both pulsed and continuous-wave pumping regimes in our system. This work provides a scalable unit design and a robust control strategy for high-rate quantum photonic circuits.