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- 实验方案
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Correlation of Small-Signal Modulation with Digital Modulation Characteristics of High-Speed Semiconductor Lasers
摘要： This paper introduces correlation of the small-signal modulation characteristics with those of digital modulation of high-speed multiple-quantum-well semiconductor laser. The accuracy of applying the common small-signal approximation to calculate the modulation bandwidth is evaluated by comparing the obtained values with those calculated by the reliable technique of time-integration of the rate equations. Also, we present correlation between the maximum bit rate and the small-signal bandwidth at given bias current and modulation index. We show that the bandwidth frequencies predicted by the small-signal approximation are higher than those calculated by the time integration. The difference increases with the increase of the bias current reaching 8 GHz when the current exceeds 3.5 times the threshold current. We predict also the modulation conditions required to achieve modulation speed as high as 40 Gbps. The ratio of the maximum bit rate to the small-signal bandwidth exceeds unity and reaches 1.6 under deep modulation with modulation index equal to 0.5.
关键词： high-speed semiconductor lasers,small-signal modulation,digital modulation,modulation bandwidth,maximum bit rate
更新于2025-09-23 15:21:01
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WDM-based bidirectional chaotic communication for semiconductor lasers system with time delay concealment
摘要： In this paper, we propose a wavelength-division-multiplexing (WDM)-based chaos communication configuration allowing for the bidirectional exchange of information. In the scheme, the output of a master semiconductor laser (MSL), is injected into slave semiconductor lasers (SSLs), drives the chaotic synchronization of SSLs with optical feedback and electro-optical phase feedback. By calculating the largest Lyapunov exponent (LLE), Lempel–Ziv complexity (LZC) and permutation entropy (PE), we find that the system can generate the chaotic signal with high complexity. We also demonstrate that the chaotic signal bandwidth obtained is as high as 24.68 GHz by selecting the suitable parameters; this configuration intrinsically conceals the electro-optical phase feedback time delay signature (TDS) and optical feedback TDS in transmitted variable; this delayed chaotic dynamics are identically synchronized when the parameters of emitter are exactly matched with that of receiver; while the external and internal parameters’ mismatch between emitter and receiver can lead to the decrease of the synchronization quality. In addition, the result reveals that the channel spacing has influence on cross-correlation coefficient (XCF) quantifying synchronization quality. At last, the messages introduced at two ends of the link can be successfully encrypted and decrypted, and we quantitatively analyze the corresponding Q-factor at different transmission rates.
关键词： Semiconductor lasers,Optical chaos,Time delay signature concealment,All-optical network,bandwidth
更新于2025-09-23 15:21:01
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Characterization of a Low-Cost, Monolithically Integrated, Tunable 10G Transmitter for Wavelength Agile PONs
摘要： Dynamically reconfigurable passive optical networks (PONs) using time-division multiplexing and dense wavelength division multiplexing will require low-cost, high-performance customer premises equipment to be economically viable. In particular, substantial cost savings can be achieved through the use of efficient re-growth free, foundry-compatible fabrication techniques. Using this strategy, this paper presents the first detailed characterization of a monolithically integrated transmitter comprised of a discretely tunable slotted Fabry–Pérot ridge waveguide laser, an absorptive modulator and a semiconductor optical amplifier (SOA) produced using a standard off-the-shelf AlInGaAs/InP multiple quantum well epitaxial structure. This first generation device demonstrates a discrete single-mode tuning range of approximately 12 nm between 1551nm and 1563 nm with a side-mode suppression ratio ≥30 dB. Moreover, the integrated modulator section is shown to support transmission at 10 Gb/s using non-return to zero on-off keying with an extinction ratio in excess of 8 dB. Furthermore, using a time-resolved chirp measurement technique to examine dynamic deviations in the set carrier frequency, the modulator section exhibits a chirp contribution of <6 GHz using test patterns with high and low frequency content. In addition, the generation of optical bursts through the application of a gating function to the SOA section was found to shift the unmodulated carrier of a typical lasing mode by ≤8 GHz for gating periods comparable with a typical PON burst durations of 125 μs which are faster than the thermal response time of the transmitter material.
关键词： Optical communications,tunable semiconductor lasers,dense wavelength division multiplexing,passive optical networks,time division multiplexing,monolithic integration
更新于2025-09-23 15:21:01
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AIP Conference Proceedings [AIP Publishing THE 7TH INTERNATIONAL CONFERENCE ON APPLIED SCIENCE AND TECHNOLOGY (ICAST 2019) - Karbala City, Iraq (27–28 March 2019)] THE 7TH INTERNATIONAL CONFERENCE ON APPLIED SCIENCE AND TECHNOLOGY (ICAST 2019) - Chaos synchronization in quantum dot semiconductor lasers with negative optoelectronic feedback
摘要： Chaos synchronization is investigated in quantum dot semiconductor lasers with negative optoelectronic feedback. Depending on the coupling strength between transmitter and receiver quantum dot semiconductor Laser. Synchronization happens when the coupling strength to the receiver matches the feedback strength to the transmitter, where the receiver output reproduces the output of the transmitter regardless of the presence of channel distortion or an encoded message. when feedback strength of transmitter, receiver quantum dot semiconductor Laser and coupling feedback strength are equal (- 0.3), time delay of transmitter, receiver quantum dot semiconductor Laser and coupling are sensitive to synchronization.
关键词： Chaos synchronization,Quantum dot semiconductor lasers,Negative optoelectronic feedback
更新于2025-09-23 15:19:57
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Complexity mapping of a photonic integrated circuit laser using a correlation-dimension-based approach
摘要： Quantifying complexity from experimental time series generated by nonlinear systems, including laser systems, remains a challenge. Methods that are based on entropy, such as permutation entropy (PE), have proven to be useful tools for the relative measure of time series complexity. However, the numerical value of PE is not readily linked to a specific type of dynamical output. Thus, the quest to calculate quantitatively meaningful fractal dimension values, such as the correlation dimension (CD), from experimental signals, is still important. A protocol for calculating minimum gradient values and their spread, an integral part of CD analysis, is used here. Minimum gradient values with small spread are presented as approximate CD values. Here-in we report mapping these values, derived from analyzing experimental time series, obtained from a 4-section photonic integrated circuit laser (PICL) across a large parameter space. The PICL is an integrated form of a semiconductor laser subject to controllable optical feedback system. The minimum gradient/approximate CD mapping shows it has some qualitatively different map regions in its dynamics as compared to a free-space-based equivalent system. We show that the minimum gradient values give insight into the dynamics even when approximate CD values cannot be determined. The agreement between the qualitative features of permutation entropy mapping and minimum gradient/approximate CD value mapping provides further support for this. Regions of time series with close to periodic and quasi-periodic dynamics are identifiable using minimum gradient value maps.
关键词： semiconductor lasers,integrated optoelectronic devices,nonlinear dynamics,complex systems,Chaos,complexity
更新于2025-09-23 15:19:57
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Giant Net Modal Gain of plasmonic quantum dot nanolaser
摘要： This work studies the net modal gain from plasmonic quantum dot (QD) nanolaser. A metal/semiconductor/metal (MSM) structure was considered to attain plasmonic nanocavity with active region contains: QDs, wetting layer (WL) and barrier layers. Band alignment between layers was used to predict their parameters. Momentum matrix element for transverse magnetic (TM) mode in QD structure was formulated. Waveguide Fermi energy was introduced and formulated, for the first time, in this work to cover the waveguide contribution (Ag metal layer) in addition to the active region. Giant net modal gain was obtained when the waveguide Fermi energy was taken into account which means that the increment comes from the material gain not from the confinement factor. The change in waveguide Fermi energy in the valence band explained the high net modal gain, where the valence band QD states are fully occupied referring to an efficient hole contribution.
关键词： Plasmonics,Semiconductor lasers,Quantum-well,-wire and -dot devices
更新于2025-09-23 15:19:57
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Study on Optical Properties and Waveguide Structure Optimization of Semiconductor Lasers with InGaAs Quantum Well
摘要： InGaAs quantum wells (QWs) are grown on GaAs substrates by metal-organic chemieal vapor deposition (MOCVD). Sample grown on substrates (100) oriented 2° off towards <111> exhibits relatively high photoluminescence (PL) intensity and narrow full-width at half-maximum (FWHM). Increasing growth rate leads to the enhancement of PL intensity and decrease of FWHM. Asymmetric waveguide layers are applied to reduce the confinement factor of base mode and increase the loss of higher-order mode.
关键词： MOCVD,waveguide structure,photoluminescence,InGaAs quantum wells,semiconductor lasers
更新于2025-09-23 15:19:57
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Applicability of small-signal laser and fiber models for passive optical networks operating at the 1550??nm window
摘要： Small-signal techniques are a useful engineering tool to estimate system performance, though small-signal models need to be tested against the large-signal from which they are derived. We show that combined small-signal models for lasers and optical fiber are valid for passive optical networks employing directly modulated semiconductor lasers, provided that the modulation extinction ratios are < 4 dB and the transmission distances < 25 km. For larger extinction ratios and longer transmission distances, large-signal approaches are needed in order to investigate system capabilities. The small-signal models break down due to the increasing adiabatic chirp in semiconductor lasers with increasing modulation current. We estimate how the small-signal models can estimate for the performance of 10 Gbit/s signal from directly modulated lasers. We verify the equivalence of the small-signal and large-signal regimes and we develop a quality metric to identify the range of fiber lengths and signal extinction ratios over which the small-regime remains valid.
关键词： Frequency,Modulation,Passive Optical Networks,Semiconductor lasers,Phase,Fiber dispersion,Numerical modelling
更新于2025-09-23 15:19:57
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Effects of Power Split Ratio and Optical Delay Phase Tuning on Stabilization of Self-Mode-Locked Quantum-Dash Lasers Subject to Dual-Loop Optical Feedback
摘要： In the present work, we report a path of RF stabilization versus delay subject to self-mode-locked (SML) two-section quantum-dash (QDash) lasers emitting at ~ 1.55 μm and operating at ~ 21 GHz repetition rate using a feedback ratio controlled and optical delay phase-dependent symmetric dual-loop optical feedback. For symmetric dual-loops (equal arms of external loops), we identify the three key parameters: power-split ratio through each cavity of the external feedback loop, optical delay phase settings, and overall feedback strength back into gain section, yields jitter stabilization on integer resonance as well as on full delay range tuning. Symmetric dual-loop feedback with two optical delay phase settings (weaker cavity set to integer resonance, fine-tuning of the stronger cavity and stronger cavity set to integer resonance, fine-tuning of a weaker cavity) and four chosen combinations of feedback ratios (-19.5:-29.03 dB, -20.6:-24.3 dB, -21:-22.7 dB, -21.3:-23 dB) has been demonstrated. Based on these four chosen combinations of feedback ratios and optical delay phase settings, a path of stabilization has been identified for SML QDash lasers using symmetric dual-loop optical feedback. Our proposed dual-loop feedback schemes provide a viable path towards the stabilization of mode-locked lasers, promising for various practical applications where ultra-stable optical pulses are highly desirable.
关键词： Mode-locked lasers,Semiconductor lasers
更新于2025-09-19 17:13:59
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All Optical Integrate and Fire Neuromorphic Node based on Single Section Quantum Dot Laser
摘要： In this work we provide numerical results concerning an all-optical inhibitory integrate and fire neuron based on a single section quantum-dot InAs/GaAs laser. The numerical model employs a detailed multi-population approach that accommodates electron-hole dynamics and can efficiently describe waveband transitions from both the ground and excited energy state. The underlying physical mechanism of waveband switching in an inhibitory neuron is unveiled and is attributed to hole-electron’s transport time asymmetries. A detailed dynamical analysis allowed the identification of suitable optical injection regimes so as to trigger highly sought neuro-computational behaviors such as rate encoding and neural spikes with picosecond temporal resolution.
关键词： Cognitive computing,neural-networks,semiconductor lasers,neuromorphic,integrate-and fire neuron,quantum-dots,excitability,optical injection,photonic neuron
更新于2025-09-19 17:13:59