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- 摘要
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- 实验方案
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Quantum cascade laser lives on the edge
摘要： Electromagnetic waves with frequencies in the terahertz range (300?GHz to 10?THz) have applications in many areas, from imaging and security screening to the atmospheric and biological sciences. Semiconductor devices called quantum cascade lasers (QCLs) provide the most compact and efficient way to generate terahertz radiation. In QCLs, electrons cascade down in energy through a series of discrete quantum energy levels, emitting a photon at each step1. But, as with all compact semi conducting lasers, QCLs are notoriously sensitive to fabrication imperfections, which results in device-to-device variability of the laser output frequency. Now, on page 246, Zeng et al.2 report the realization of a terahertz QCL that is insensitive to such disorder. This achievement opens the door for terahertz lasers and optoelectronics that have unprecedented stability and fabrication reproducibility.
关键词： topological protection,terahertz radiation,topological insulators,photonics,quantum cascade lasers
更新于2025-09-19 17:13:59
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Electrically pumped topological laser with valley edge modes
摘要： Quantum cascade lasers are compact, electrically pumped light sources in the technologically important mid-infrared and terahertz region of the electromagnetic spectrum1,2. Recently, the concept of topology3 has been expanded from condensed matter physics into photonics4, giving rise to a new type of lasing5–8 using topologically protected photonic modes that can efficiently bypass corners and defects4. Previous demonstrations of topological lasers have required an external laser source for optical pumping and have operated in the conventional optical frequency regime5–8. Here we demonstrate an electrically pumped terahertz quantum cascade laser based on topologically protected valley edge states9–11. Unlike topological lasers that rely on large-scale features to impart topological protection, our compact design makes use of the valley degree of freedom in photonic crystals10,11, analogous to two-dimensional gapped valleytronic materials12. Lasing with regularly spaced emission peaks occurs in a sharp-cornered triangular cavity, even if perturbations are introduced into the underlying structure, owing to the existence of topologically protected valley edge states that circulate around the cavity without experiencing localization. We probe the properties of the topological lasing modes by adding different outcouplers to the topological cavity. The laser based on valley edge states may open routes to the practical use of topological protection in electrically driven laser sources.
关键词： terahertz,topological photonics,valley edge states,Quantum cascade lasers,electrically pumped lasers
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Solution-processed ultrathin SnO <sub/>2</sub> passivation of Absorber/Buffer Heterointerface and Grain Boundaries for High Efficiency Kesterite Cu <sub/>2</sub> ZnSnS <sub/>4</sub> Solar Cells
摘要： InP-based high electron mobility transistors (InP-HEMTs) and graphene-channel FETs (G-FETs) are experimentally examined as photonic frequency converters for future broadband optical and wireless communication systems. Optoelectronic properties and three-terminal functionalities of the InP-HEMTs and G-FETs are exploited to perform single-chip photonic double-mixing operation over the 120 GHz wireless communication band. A 10 Gbit/s-class data signal on a 112.5 GHz carrier is mixed down to a 25 GHz IF band with an 87.5 GHz LO signal that is simultaneously self-generated from an optically injected photomixed beat note. The results suggest that the intrinsic channel of the G-FET can achieve a speed performance that is superior to that of an InP-HEMT having an equivalent device feature size. The reduction of the extrinsic parasitic resistances and the implementation of an efficient photo-absorption structure in the G-FET may allow a millimeter-wave and sub-THz photonic frequency conversion with a sufficiently high conversion gain for practical purposes.
关键词： millimeter wave photonics,radio access networks,graphene,FETs,HEMTs,InP,millimeter wave communication,frequency conversion
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Spectral Impacts on the Performance of mc-Si and New-Generation CdTe Photovoltaics in the Brazilian Northeast
摘要： We have developed a 5 × 5 mm2 compact silicon-photonic receiver with a 28-nm CMOS transimpedance-amplifier (TIA) chip. The receiver chip was designed using a photonics—electronics convergence design technique for the realization of high-speed and high-efficiency operation because the interfaces of the optical and electrical components greatly influence the receiver characteristics. Optical pins were used to obtain easy optical alignment between the multimode fibers and the germanium photodetectors. An aluminum stripline between the PD and the TIA enhanced the 3-dB bandwidth because its characteristic impedance is greater than the TIA input impedance. Coplanar waveguides (CPWs) on the etched SOI wafer achieved a low insertion loss because the overlap between the electric fields of the CPWs and the silicon layer was reduced. We demonstrated 25-Gb/s error-free operation at both 25 and at 85 °C. The minimum sensitivities and power consumptions of the receivers were ?11.0 dBm and 2.3 mW/Gb/s at 25 °C and ?10.2 dBm and 2.5 mW/Gb/s at 85 °C, respectively. These results show that our receiver can be applied for practical use at high temperatures.
关键词： optoelectronic integrated circuit,silicon photonics,optical interconnections,CMOS transimpedance amplifier,optical receivers,multimode fiber transmission
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE) - Aswan City, Egypt (2019.10.23-2019.10.25)] 2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE) - Analysis, Design and Simulation of a DC Photovoltaic Microgrid with Electric Vehicle Charging Capability
摘要： Optical fibre transmission has enabled greatly increased transmission rates with 10 Gb/s common in local area networks. End users find wireless access highly convenient for mobile communication. However, limited spectrum availability at microwave frequencies results in per-user transmission rates limited to much lower values, e.g., 500 Mb/s for 5-GHz band IEEE 802.11ac. Extending the high data-rate capacity of optical fiber transmission to wireless devices requires greatly increased carrier frequencies. This paper will describe how photonic techniques can enable ultrahigh capacity wireless data distribution and transmission using signals at millimeter-wave and TeraHertz (THz) frequencies.
关键词： optical heterodyne,optical mixing,optical phase lock loops,millimeter (mm)-wave generation,microwave photonics,photonic integrated circuits,Broadband communication,semiconductor lasers
更新于2025-09-19 17:13:59
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[IEEE 2019 Photonics North (PN) - Quebec City, QC, Canada (2019.5.21-2019.5.23)] 2019 Photonics North (PN) - Progress in Passively Mode-Locked 2-Micron Tm and Ho Bulk Solid-State Lasers
摘要： The increasing number of computational servers in data centers is imposing tighter constraints on the networking infrastructure. Scalable power efficient optical interconnect network becomes necessary to leverage the bandwidth capacity of current electronic switches or opto-electronic components. Hence, novel optical interconnect technology can enhance the network capacity by harnessing the feasibility of simultaneous processing of optical signal in the wavelength and time domains. In this paper, we present a four channel optical passive wavelength-striped mapping (PWSM) device, which passively time compresses/expands serial packets through optical wavelength multiplexing/demultiplexing. The PWSM device, which has a 1 × 4 channel optical wavelength demultiplexer with integrated optical delay lines, is designed in a low-loss Si3N4 (propagation loss ～3.1 dB/m) waveguide platform. The PWSM device multiplexes/demultiplexes four WDM channels and offsets in time the adjacent channels to optically serialize/deserialize data packets. In this demonstration, a 64 ns long data packet is formed at the output of the device by combining four 16 ns data segments of the packet in time domain. Incremental optical insertion loss between adjacent channels is ～9.7 dB due to the integrated passive optical delay waveguides. The data rate of the four segmented packets and the combined packet is 25 Gb/sec. We have measured a bit error rate performance below 1 ×10?9 for the 64 ns serial data packet regenerated by the PWSM device for a received optical power of –6.7 dBm.
关键词： silica and silicon nitride photonics,wavelength filtering devices,Photonic integrated circuits
更新于2025-09-19 17:13:59
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Optimal Photonic Crystal Cavities for Coupling Nanoemitters to Photonic Integrated Circuits
摘要： Photonic integrated circuits that are manufactured with mature semiconductor technology hold great promise for realizing scalable quantum technology. Efficient interfaces between quantum emitters and nanophotonic devices are crucial building blocks for such implementations on silicon chips. These interfaces can be realized as nanobeam optical cavities with high quality factors and wavelength-scale mode volumes, thus providing enhanced coupling between nano-scale quantum emitters and nanophotonic circuits. Realizing such resonant structures is particularly challenging for the visible wavelength range, where many of the currently considered quantum emitters operate, and if compatibility with modern semiconductor nanofabrication processes is desired. Here, it is shown that photonic crystal nanobeam cavities for the visible spectrum can be designed and fabricated directly on-substrate with high quality factors and small mode volumes. Designs are compared based on deterministic and mode-matching methods and the latter is found advantageous for on-substrate realizations. The results pave the way for integrating quantum emitters with nanophotonic circuits for applications in quantum technology.
关键词： CMOS compatible,photonic crystal cavities,integrated photonics,high quality factor
更新于2025-09-19 17:13:59
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[IEEE 2020 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus) - St. Petersburg and Moscow, Russia (2020.1.27-2020.1.30)] 2020 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus) - Optical Signal Propagation Simulation in Rectangular Microwaveguides
摘要： The simulation of the optical modes that propagate inside the microwaveguides of a rectangular cross-section was carried out. The impact of geometry of the microwaveguide cross-section on the group velocity of the modes is analyzed. It is demonstrated that the group velocity has a non-linear dependence on a microwaveguide core width. This dependence is determined by the energy redistribution between the core and the cladding of the microwaveguide.
关键词： group velocity,microwave photonics,integrated optics,propagation loss,optical microwaveguides
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Numerical modeling and experimental realization of wide bandgap ZnTe-based solar cells for semi-transparent PV application
摘要： InP-based high electron mobility transistors (InP-HEMTs) and graphene-channel FETs (G-FETs) are experimentally examined as photonic frequency converters for future broadband optical and wireless communication systems. Optoelectronic properties and three-terminal functionalities of the InP-HEMTs and G-FETs are exploited to perform single-chip photonic double-mixing operation over the 120 GHz wireless communication band. A 10 Gbit/s-class data signal on a 112.5 GHz carrier is mixed down to a 25 GHz IF band with an 87.5 GHz LO signal that is simultaneously self-generated from an optically injected photomixed beat note. The results suggest that the intrinsic channel of the G-FET can achieve a speed performance that is superior to that of an InP-HEMT having an equivalent device feature size. The reduction of the extrinsic parasitic resistances and the implementation of an efficient photo-absorption structure in the G-FET may allow a millimeter-wave and sub-THz photonic frequency conversion with a sufficiently high conversion gain for practical purposes.
关键词： millimeter wave photonics,radio access networks,graphene,FETs,HEMTs,InP,millimeter wave communication,frequency conversion
更新于2025-09-19 17:13:59
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A compact 120??GHz monolithic silicon-on-silica electro-optic modulator
摘要： A novel electro-optic modulator using the silicon-on-silica platform is proposed. The modulator utilizes a modified version of the gate-all-around switching mechanism which is well-known in MOSFET transistors. The waveguide silicon core is surrounded by oxide and metal to increase the effect of the applied voltage in charge depletion and accumulation and hence the optical phase shift. The modulator features a very high switching speed of 120 GHz, thanks to its very low capacitance, with a total insertion loss of 4.6 dB and a phase-shifter length of 500 μm. The proposed modulator can therefore serve in high speed applications such as the backbone circuits of the new 5G telecommunications networks.
关键词： Integrated optics,Electro-optic modulators,Silicon photonics
更新于2025-09-19 17:13:59