- 标题
- 摘要
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- 实验方案
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Regimes of bandwidth enhancement in coupled-cavity semiconductor laser using photon–photon resonance
摘要： In the last decade, different solutions were proposed to boost the transmission bitrate of semiconductor lasers. Here, we focus on applying optical feedback to a semiconductor laser from an external cavity in order to induce enhancement of the modulation bandwidth up to 50 GHz as well as resonant modulation (RM) around frequencies approaching 60 GHz. High-speed modulation up to 90 Gbps under none-return to zero operation and a 45 Gbaud using pulse amplitude modulation-4 signals are predicted. Both types of improving the modulation performance of the laser are attributed to the photon–photon resonance (PPR) effect. The regimes of the external power reflectivity that correspond to both types of modulation response are specified. Comprehensive simulations are introduced to correlate the PPR frequency to the RM frequencies of the non-modulated coupled-cavity laser. Dependencies of the enhanced BW and PPR frequency on the cavity length and bias current are elucidated.
关键词： optical feedback,photon–photon resonance,modulation bandwidth,high-speed modulation,semiconductor lasers
更新于2025-09-11 14:15:04
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Reduction of the chromatic dispersion and chirping effects by using an injection-locked and directly intensity-modulated Fabry–Pérot laser in point-to-point optical access networks
摘要： We present recent improvements achieved for two important transmission parameters—dispersion, induced by the optical fiber, and the chirp parameter of the laser source—in a directly modulated system based on an injection-locked and directly modulated Fabry–Pérot laser diode for high-speed optical access networks with a point-to-point topology. Measurements in the 20-GHz range of the frequency response for distances up to 35 km are conducted by carefully adjusting the optical power and frequency detuning of the distributed master laser in the central office, thereby overcoming the problem of chromatic dispersion in high-speed optical access. Moreover, the enhancements make it possible to increase the transmission distance when a 1550-nm Fabry–Pérot laser is used as the light source in the central office of a point-to-point optical access network by distributing the seed light into numerous downstream lasers. This improvement to the injection-locked Fabry–Pérot laser is expected to extend the length of already-built, fiber-to-the-home, point-to-point networks with a simple upgrade in the central office without prejudicing the terminal equipment.
关键词： Semiconductor lasers,Injection locking,Frequency response,Modulation
更新于2025-09-11 14:15:04
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Weyl points in systems of multiple semiconductor-superconductor quantum dots
摘要： As an analogy to the Weyl point in k-space, we search for energy levels which close at a single point as a function of a three-dimensional parameter space. Such points are topologically protected in the sense that any perturbation which acts on the two-level subsystem can be corrected by tuning the control parameters. We find that parameter-controlled Weyl points are ubiquitous in semiconductor-superconductor quantum dots and that they are deeply related to Majorana zero modes. In this paper, we present several semiconductor-superconductor quantum-dot devices which host parameter-controlled Weyl points. Furthermore, we show how these points can be observed experimentally via conductance measurements.
关键词： semiconductor-superconductor quantum dots,conductance measurements,Majorana zero modes,Weyl points
更新于2025-09-11 14:15:04
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Electron-hole superfluidity controlled by a periodic potential
摘要： We propose controlling an electron-hole super?uid in semiconductor coupled quantum wells and double layers of a two-dimensional (2D) material by an external periodic ?eld. This can be created either by the gates periodically located and attached to the quantum wells or double layers of the 2D material or by the moiré pattern of two twisted layers. The dependence of the electron-hole pairing order parameter on the temperature, the charge carrier density, and the gate parameters is obtained by minimization of the mean-?eld free energy. The second-order phase transition between super?uid and electron-hole plasma, controlled by the external periodic gate ?eld, is analyzed for different parameters.
关键词： mean-?eld free energy,semiconductor coupled quantum wells,electron-hole super?uid,phase transition,external periodic ?eld,two-dimensional material
更新于2025-09-11 14:15:04
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Integration of Mid-Infrared Light Sources on Silicon Based Waveguide Platforms in 3.5 — 4.7 μm Wavelength Range
摘要： Mid-infrared light sources are attracting attention for use in spectroscopic sensing, thermal imaging, and infrared countermeasures. Integration of these sources on Si-based waveguides allows for more functional and complex photonic circuits to be integrated on a single chip. This paper focuses on the key aspects of this integrated platform. The operation of silicon-on-insulator waveguides beyond 4.0 μm wavelength with increasing waveguide core thickness is discussed, and the effects of various cladding materials on waveguide propagation loss is demonstrated. Low loss waveguides and Mach-Zehnder interferometers in Ge-on-Si waveguide platform are discussed and beam combiners in the form of arrayed waveguide gratings are demonstrated in both the platforms. Interband cascade lasers are integrated on silicon-on-insulator waveguides with direct bonding to realize Fabry-Perot lasers. Power scaling of integrated lasers is validated by integrating quantum cascade lasers with silicon-on-insulator beam combiners. Results for the first integrated Fabry-Perot quantum cascade lasers on Ge-on-Si waveguides are discussed, together with the potential use of these waveguides to provide a better heat sink for integrated mid-infrared light sources.
关键词： Quantum Cascade Lasers,Silicon Photonics,Interband Cascade Lasers,Semiconductor Waveguides
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE 2nd Ukraine Conference on Electrical and Computer Engineering (UKRCON) - Lviv, Ukraine (2019.7.2-2019.7.6)] 2019 IEEE 2nd Ukraine Conference on Electrical and Computer Engineering (UKRCON) - Gyrotropic Semiconductor-Ferrite One Dimensional Magnetophotonic Crystals
摘要： Dispersion gyrotropic magnetophotonic one-dimensional crystal with semiconductor and ferrite layers is obtained. Analysis of the dispersion diagrams for different values of the anisotropic layers effective permittivity and permeability is carried out. Dispersion properties of the structure for surface and bulk waves TE and TM modes are analyzed for different material parameters and geometrical sizes of magnetophotonic crystals. Surface and bulk wave regimes are investigated. Polarization indifference for structure under investigation is shown.
关键词： ferrite,gyrotropic media,dispersion characteristics,one-dimensional magnetophotonic crystal,semiconductor
更新于2025-09-11 14:15:04
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Tunable Dual-Wavelength Self-injection Locked InGaN/GaN Green Laser Diode
摘要： We implemented a tunable dual-longitudinal-mode spacing InGaN/GaN green (521–528 nm) laser diode by employing a self-injection locking scheme that is based on an external cavity configuration and utilizing either a high or partial-reflecting mirror. A tunable longitudinal-mode spacing of 0.20 – 5.96 nm was accomplished, corresponding to a calculated frequency difference of 0.22–6.51 THz, as a result. The influence of operating current and temperature on the system performance was also investigated with a measured maximum side-mode-suppression ratio of 30.4 dB and minimum dual-mode peak optical power ratio of 0.03 dB. To shed light on the operation of the dual-wavelength device arising from the tunable longitudinal-mode spacing mechanism, the underlying physics is qualitatively described. To the best of our knowledge, this tunable longitudinal-mode-spacing dual-wavelength device is novel, and has potential applications as an alternative means in millimeter wave and THz generation, thus possibly addressing the terahertz technology gap. The dual-wavelength operation is also attractive for high-resolution imaging and broadband wireless communication.
关键词： InGaN/GaN visible lasers,Dual wavelength lasers,optical injection locking,semiconductor lasers
更新于2025-09-11 14:15:04
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[IEEE 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - Fukuoka, Japan (2019.7.7-2019.7.11)] 2019 24th OptoElectronics and Communications Conference (OECC) and 2019 International Conference on Photonics in Switching and Computing (PSC) - An integrated LAN-WDM 400-Gb/s (53Gbaud-PAM4) EML TOSA
摘要： We demonstrated an integrated LAN-WDM 400-Gb/s (53Gbaud-PAM4) EML TOSA. Low power consumption less than 1.3 W between -5 °C and 80 °C was obtained besides the measured TDECQs below 2.45 dB for all lanes.
关键词： Semiconductor lasers,Packaging technology of photonic devices and circuits
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Passively Mode-Locked Quantum-Well Semiconductor Laser Subject to Ultra-Short Optical Self-Feedback with Nanometric Fine-Delay
摘要： Monolithic passively mode-locked (PML) semiconductor lasers emitting at 1070 nm are promising ultra-fast sources for new prospective photonic transport systems in a 1 μm transmission window waveband [1,2]. As residual optical feedback (OFB) can deteriorate the emitted optical pulse trains, experimental studies exploring the immunity of the laser against perturbations by unintentional OFB with nanometric precision are demanded, but however yet lacking. We study experimentally the impact of sub-wavelength scale fine-delay controlled short-cavity OFB on the optical spectra, repetition rate (RR) and average optical output power of a monolithic PML semiconductor quantum-well (QW) laser. The laser emits picosecond short optical pulses at 1070 nm with a free-running RR of 13.6 GHz corresponding to an internal pulse round-trip time of 75 ps. A similar device has been investigated in [2]. OFB is provided by a free-space external cavity exhibiting a macroscopic delay length Tmac ranging from 145 ps up to 275 ps round-trip time. A wedged glass on a high-precision linear translation stage provides delay with nanometric precision. We first study the optical pulsed emission in dependence of changing Tmac from 145 ps to 275 ps. The color-coded measured nonlinear auto-correlation (AC) signals and RRs are depicted in Fig. 1(a) and Fig. 1(b), respectively.
关键词： passively mode-locked,ultra-short optical self-feedback,quantum-well semiconductor laser,nanometric fine-delay
更新于2025-09-11 14:15:04
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Development of Germanium-Based Wafer-Bonded Four-Junction Solar Cells
摘要： Multijunction solar cells with four junctions are expected to be the next-generation technology for both space and concentrator photovoltaic applications. Most commercial triple-junction solar cells are today grown on germanium, which also forms the bottom subcell. Extending this concept to four junctions with an additional ～1-eV subcell was proven to be challenging. We investigate a new cell concept, which uses direct wafer bonding to combine a metamorphic GaInAs/Ge bottom tandem solar cell with a GaInP/AlGaAs top tandem on GaAs resulting in a monolithic four-junction cell on germanium. This article summarizes results of the cell developments, which have been resulting in a four-junction concentrator cell with 42% ef?ciency. We implemented a new passivated Ge backside technology to enhance the current generation in the Ge junction, and we propose realistic steps to realize solar cells with 45% ef?ciency using this cell architecture.
关键词： photovoltaics,concentrator,photovoltaic cells,germanium,III-V semiconductor materials
更新于2025-09-11 14:15:04