- 标题
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- 实验方案
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Nanotube mode-locked, wavelength and pulsewidth tunable thulium fiber laser
摘要： Mode-locked oscillators with highly tunable output characteristics are desirable for a range of applications. Here, with a custom-made tunable filter, we demonstrate a carbon nanotube (CNT) mode-locked thulium fiber laser with widely tunable wavelength, spectral bandwidth, and pulse duration. The demonstrated laser’s wavelength tuning range reached 300 nm (from 1733 nm to 2033 nm), which is the widest-ever that was reported for rare-earth ion doped fiber oscillators in the near-infrared. At each wavelength, the pulse duration can be regulated by changing the filter’s bandwidth. For example, at ~1902 nm, the pulse duration can be adjusted from 0.9 ps to 6.4 ps (the corresponding output spectral bandwidth from 4.3 nm to 0.6 nm). Furthermore, we experimentally and numerically study the spectral evolution of the mode-locked laser in presence of a tunable filter, a topic that has not been thoroughly investigated for thulium-doped fiber lasers. The detailed dynamical change of the mode-locked spectra is presented and we observed gradual suppression of the Kelly sidebands as the filter’s bandwidth is reduced. Further, using the polarization-maintaiing (PM) cavity ensures that the laser is stable and the output laser’s polarization extinction ratio is measured to exceed 20 dB.
关键词： thulium fiber laser,spectral bandwidth,polarization-maintaiing cavity,Kelly sidebands,tunable wavelength,pulse duration,Mode-locked oscillators,carbon nanotube
更新于2025-11-28 14:23:57
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Single-frequency fibre laser at 1030?nm based on gain bandwidth compression
摘要： We demonstrate a single-frequency linear cavity fiber laser at 1030 nm with a distributed Bragg reflector cavity configuration. Despite the fact that the combination of the cavity length of the fiber laser and the reflection band of the output FBG cannot satisfy the condition of single-longitudinal mode oscillation, the single-frequency lasing is still realized by the proper temperature control of two FBGs to narrow the gain bandwidth. Under the respective temperature of two FBGs of 43.4 °C and 9 °C, the laser linewidth of around 9.6 kHz is achieved at a pump power of 113 mW. The relative noise intensity for frequencies of above 1.5 MHz is about ?140 dB Hz?1. The maximum output power of 126.2 mW is obtained with the slope efficiency of about 28%.
关键词： fibre laser,single-frequency,gain bandwidth compression,distributed Bragg reflector
更新于2025-11-28 14:23:57
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[Communications in Computer and Information Science] Futuristic Trends in Network and Communication Technologies Volume 958 (First International Conference, FTNCT 2018, Solan, India, February 9–10, 2018, Revised Selected Papers) || Future Perspectives in Elastic Optical Networks
摘要： The new generation Elastic Optical Networks (EONs) based on Orthogonal Frequency Division Multiplexing (OFDM) can accommodate exponentially increasing heterogeneous data traffic efficiently and economically. In EONs, the optimum channel spacing between various subcarriers is very crucial for its efficient performance. The use of Sub-Carrier Multiplexing (SCM) in EONs is visualized as an evolving field. This paper present the evaluation of SCM based EONs for both mathematical and simulative model. The designed SCM-EON network is analytically evaluated for its performance with different modulation techniques (Direct Modulation and External Modulation). The performance of system is also evaluated for amplification using Semiconductor Optical Amplifier (SOA) and Erbium Doped Fiber Amplifier (EDFA). Simulative results show that Optical Phase Modulation (OPM) along with EDFA offers enhanced performance for the proposed model. It has also been observed that OPM is a better technique for SCM and hence it can be deduced that the combination will boost EONs efficiency in handling network resources.
关键词： SCM,Elastic Optical Networks,OFDM,EDFA,OPM,Bandwidth variable-wavelength cross-connects (BV-WXC),Quadrature Amplitude Modulation (QAM),Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM),Mach-Zehnder modulator (MZM)
更新于2025-09-23 15:23:52
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Tunable Wide-Bandwidth Resonators Based on Layered Gallium Sulfide
摘要： Wide-bandwidth and high-frequency operation are the two desired properties from resonators in a wide range of applications, such as communication devices, energy harvesters, inertial sensors, and electronic components. However, achieving both of these prerequisites along with detectable vibration amplitudes is very challenging. Herein, nano-electromechanical resonators based on layered gallium sulfide (GaS) are demonstrated. These resonators show resonance frequencies in the range of 10–25 MHz under ambient conditions and a bandwidth of hundreds of kilohertz, which can be simply tuned by predetermining the dimensions of the devices. Therefore, this study emphasizes that, in addition to excellent performances in electronic and optoelectronic applications, GaS can also be implemented as a high performance core element in nanoresonator applications.
关键词： electromechanical properties,wide-bandwidth resonators,gallium sulfide,2D materials
更新于2025-09-23 15:23:52
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Analysis of the Cost and Energy Efficiency of Future Hybrid and Heterogeneous Optical Networks
摘要： Orthogonal frequency division multiplexing (OFDM) promises to provide the necessary boost in the core networks’ capacity along with the required flexibility in order to cope with the Internet’s growing heterogeneous traffic. At the same time, wavelength division multiplexing (WDM) technology remains a cost-effective and reliable solution especially for long-haul transmission. Due to the higher implementation cost of optical OFDM transmission technology, it is expected that OFDM-based bandwidth variable transponders (BVT) will co-exist with conventional WDM ones. In this paper, we provide an integer linear programming (ILP) formulation that minimizes the cost and power consumption of such hybrid architecture and then a comparison is made with a pure OFDM-based elastic optical network (EON) and a mixed line rate (MLR) WDM optical network in order to evaluate their cost and energy efficiency.
关键词： ILP,WDM,Hybrid Optical Network,Elastic Optical Network,Bandwidth Variable Transponder
更新于2025-09-23 15:23:52
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Spoof Plasmon Interconnects— Communications beyond RC Limit
摘要： T HE inception of spoof surface plasmon polariton (SSPP) mode realized in planar, patterned conductors to manage light beyond diffraction limit at a chosen frequency garnered significant attention of late. We show that, an SSPP channel can be chosen to act in two distinct ways: first, as a regular RC limited electrical interconnect at low frequencies; and second, as an exotic, beyond RC limit communication channel near its resonant frequency by binding the electromagnetic field on its surface to the elimination of capacitance C. A dynamic transformation between these two modes can constitute an energy economic, tera-scale inter-chip hybrid communication network. We have investigated theoretical limits on the information transfer capability of SSPP interconnects. We show that, a geometry dependent trade-off relation between cross-talk limited bandwidth density and information traveling length emerges in SSPP based communication networks. According to our analysis, a bandwidth density of 1 Gbps/μm is attainable in SSPP communication network with ～ 10 mm information transfer distance, where each channel can carry ～ 300 Gbps information with nominal cross-talk.
关键词： Interconnect,Spoof Plasmon,bandwidth,Terahertz,thermal noise,information capacity
更新于2025-09-23 15:23:52
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High Bandwidth Non-Resonant High Voltage Generator for X-Ray Systems
摘要： High-voltage supplies for medical X-ray systems require up to 150 kV DC at up to 100 kW to supply the tube. The challenge for the power supply however is not only to deal with the high voltage and high power demand, but also to provide short voltage rise- and fall times in the range of 100μs. A coupled interleaved circuit variant of a single active bridge concept, the coupled interleaved single active bridge converter, is demonstrated in this work providing very fast output voltage control due to its non-resonant structure. The conduction modes of the circuit are analysed in detail and compared to the uncoupled interleaved single active bridge approach, demonstrating the advantages of low inverter RMS current, zero voltage switching (or at least zero current switching) over the full operating range with constant switching frequency. Analytic expressions for the output current-duty cycle relationship are provided. Experiments on a 60 kW (low voltage equivalent) prototype show that rise times as low as five switching cycles are possible, allowing to reach the target of 100μs rise time using a switching frequency of only 50 kHz.
关键词： DC-DC power conversion,high bandwidth,high voltage generator,X-ray generator
更新于2025-09-23 15:22:29
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A Wideband Polarization-Reconfigurable Water Dielectric Resonator Antenna
摘要： A water dielectric resonator antenna (DRA) with reconfiguration and broadband characteristics is presented. By injecting pure water into various cavities of the plexiglass holder, the antenna can be switched among left hand circular polarization (LHCP), right hand circular polarization (RHCP) and linear polarization (LP) in almost the same operating frequency range. With the high relative permittivity, water acts as a dielectric resonator as well as an interface similar to electric wall to form a broad axial ratio bandwidth. Thus a broad usable bandwidth is measured to be over 22%, and the measured radiation efficiency and realized gain centralize in 60%-70% and 3-4 dBi respectively.
关键词： dielectric resonator antenna,water antenna,broad bandwidth,dielectric dense patch antenna,reconfigurability
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Austin, TX, USA (2018.9.24-2018.9.26)] 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - An Improved Random Path Length Algorithm for p-i-n and Staircase Avalanche Photodiodes
摘要： We present an improved Random Path Length algorithm to accurately and efficiently estimate the design space of heterostructure avalanche photodiodes (APDs) in terms of gain, noise and bandwidth without any need of full Monte Carlo transport simulations. The underlying nonlocal model for impact ionization goes beyond the Dead Space concept and it is suited to handle staircase structures composed by a superlattice of III-V compounds as well as thick and thin p-i-n APDs. The model parameters have been calibrated on GaAs and Al_xGa_{1-x}As p-i-n APDs in a previous work. In this work GaAs p-i-n APDs are compared to staircase structures in terms of noise and bandwidth.
关键词： Impact Ionization,Avalanche Multiplication,Random Path Length,Staircase APDs,Bandwidth,Excess Noise Factor,Simulation
更新于2025-09-23 15:22:29
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Design of a Circularly Polarized Dielectric Resonator Antenna with Wide Bandwidth and Low Axial Ratio Values
摘要： A circularly polarized (CP) dielectric resonator antenna (DRA) with wide bandwidth and low axial ratio (AR) values is presented in this communication. The antenna consists of a stacked DRA, and it is fed by a substrate integrated waveguide (SIW) coupling slot from the bottom. The stacked DRA structure, with high permittivity dielectric strips layered on low permittivity substrate, is adopted for bandwidth and gain benefits. Here, a pair of dielectric strips rather than a single one is placed above the coupling slot with 45° inclination for generating good CP radiation, and it is elaborately designed to provide three closely coupled CP modes, constituting a wide operating bandwidth. To facilitate the application in antenna array, a cavity-backed antenna design along with a 2×2 sub-array are further presented. To verify the design, a sub-array prototype is developed and tested at Ku-band for satellite applications, showing an impedance bandwidth of 25.1%, a wide 1-dB AR bandwidth of 15.6%, and a peak gain of 15.1dBi.
关键词： substrate integrated waveguide,low axial ratio values,wide bandwidth,Dielectric resonator antenna
更新于2025-09-23 15:22:29