Quantum Dot Semiconductor Lasers Research Articles

Various nonlinear transitions of a self-assembled quantum dot (SA-QD) semiconductor laser subject to negative optoelectronic feedback

Various nonlinear transitions of a self-assembled quantum dot (SA-QD) semiconductor laser subject to negative optoelectronic feedback

Quantum dot laser dynamics and external filtered modes under the influence of double-filtered optical feedback

We study the dynamics and solution structure of a semiconductor quantum dot (QD) laser system that gets delayed FOF from two filter loops: the double-filtered optical feedback (DFOF) laser. Two filters are utilized in optical communication applications to regulate and stabilize the laser output, which served as the inspiration for this study. The entire mathematical model of the DFOF laser consists of delay differential equations for the inversion of the QD laser with the two filters. We focus on continuous-wave DFOF QD laser systems because reliable laser source operation is essential for optical communication applications. These basic responses are called external filtered modes (EFMs), and they significantly affect the stability and structure of the EFMs as well as the laser’s performance in comparison to the single FOF QD laser. The parameter C eff is a measure of the interference between the two filter fields, and it is identified as a key to the EFM structure. To analyse how the structure and stability of the EFMs depend on all the filter and feedback loop parameters, we make extensive use of the EFM surface in the (Ω(ω s), C eff , Y s )-space of frequency s, filter phase difference C eff , and population inversion Y s of the QD laser. In general, the EFM surface is the natural object that should be taken into account to comprehend the dynamical characteristics of the DFOF laser. In general, our study involved searching for regions in the QD laser output with stable amplitude and frequency. The time delay suppression is dependent on the spectral width Λ of the filter and how far it is from the solitary laser frequency, according to numerical calculations. In addition to studying the dynamic behavior using a bifurcation diagram at the filter working areas, the results showed two stages of operation due to the occurrence of phase entanglement stochastic.

Optically injected quantum dot lasers and its complex dynamics

Abstract Lasers are paradigmatic examples of nonlinear systems and have played a crucial role in developing nonlinear dynamics into an interdisciplinary topic. Indeed, a freely operating laser represents a nontrivial system, but the phenomena that occur are much more interesting when the laser is exposed to external factors such as optical feedback (OFB) and optical injection (OI). This paper deals with the analysis of the dynamic behavior of a quantum dot semiconductor laser (QDSL) model under the influence of optical injection from another laser. The proposed model was studied numerically with the help of MATLAB. A QDSL system with optical injection was proposed and studied numerically. The quantum dot (QD) laser was used, which is a quantum semiconductor laser and has strong stability without external perturbation. When it is subjected to feedback, it has a critical effect on the follower laser and changes its stable behavior before injection to a set of nonlinear dynamics. The effect of both optical feedback strength and the delay time on the performance and behavior of the bifurcation patterns in the follower laser output was studied, taking into account changing the bifurcation parameters, the injection force k, the slave laser frequency, and the slave laser delay time. The behavior of the slave was studied each time and compared with the behavior of the master. We observed the chaotic paths (essentially stable and continuous pulsating oscillations evolving into periodic and semi-periodic oscillations and then chaotic ones). The time series corresponding to the bifurcation diagrams and the probability of the time interval between spikes and attractors were studied.

Correlation coefficient of nanolaser based on quantum dot semiconductor laser through optoelectronic feedback an open-loop system

Correlation coefficient of nanolaser based on quantum dot semiconductor laser through optoelectronic feedback an open-loop system

General and Complete Synchronization of Mutual Coupling System of Quantum Dot Semiconductor Lasers With Optical Feedback

Abstract The study examines an extensive and complete synchronization of optimal feedback with quantum dot semiconductor laser mutual coupling system. This has been achieved by resolving the transmitter and receiver equations of the quantum dot lasers. Numerous crisis areas have been observed at the time of investigating the relationship between photon density and time. The authors have selected an optimal time delay for the optical feedback so as to render an appropriate situation for intermittent dynamics. The study analyses the impact created by a long external cavity of QDSL upon the synchronization process in this mutual coupling system, in the presence of the enhancement factor of (α =3).

Matching points of nanolaser based on quantum dot semiconductor laser for positive and negative optoelectronic feedback strength

Matching points of nanolaser based on quantum dot semiconductor laser for positive and negative optoelectronic feedback strength

Uniform spike trains in optically injected quantum cascade oscillators.

It has been experimentally and theoretically analyzed that noise-induced excitability in quantum well and quantum dot semiconductor laser systems usually produces sharp spike patterns of non-uniform amplitude. In this paper, we experimentally record that a quantum cascade oscillator injected externally with a monochromatic laser beam exhibits a series of highly uniform spike trains, which occur in the proximity of the saddle-node bifurcation. Theoretical analysis based on a properly designed single-mode rate equation model endowed with quantum noise reveals that this high uniformity has its primary origin in the ultrashort carrier lifetime of the quantum cascade laser gain medium that is typically close to 1 ps.

External Filtered Modes of a Quantum Dot Laser Under the Influence of Double-Filtered Optical Feedback

When semiconductor lasers SLs are exposed to filtered optical feedback (FOB), they behave in two different ways. Under weak or strong feedback, the first is a singularly stable longitudinal mode with a small linewidth. The second is the so-called coherence breakdown condition, which also includes low frequency fluctuations (LFF) and chaotic oscillations. The latter has received a lot of attention recently due to the possible uses of chaotic lasers in chaotic lidar, covert communications, and chaotic correlation time-domain optical reflectometers, while the former has received a lot of research in recent years. We investigate the behavior of a quantum dot (QD) semiconductor laser subject to FOF from two separate external cavities both, numerically and experimentally. Our findings show that the second FOF allows for rich adjustment of the laser frequency. Our analysis of double-filtered optical feedback (DFOF) lasers is on fundamental solutions, sometimes referred to as continuous waves (CW) or external filtering modes (EFM), which result in a QD laser output with constant amplitude and frequency. The time delay suppression is dependent on the spectral width of the filter and how far it is from the solitary laser frequency, according to numerical calculations.

The effect of optical polarized feedback on dynamics of quantum dot semiconductor lasers

The effect of optical polarized feedback on dynamics of quantum dot semiconductor lasers

Designing photonic crystal waveguide–based quantum dot semiconductor lasers for optical telecommunication applications

Designing photonic crystal waveguide–based quantum dot semiconductor lasers for optical telecommunication applications

Wave mixing efficiency in InAs/GaAs semiconductor quantum dot optical amplifiers and lasers

The nonlinear features of both semiconductor optical amplifiers (SOAs) and semiconductor lasers, which are made from the same InAs/GaAs quantum dot (QD) wafers, are investigated in detail. By employing pump-probe driven four-wave mixing as an experimental tool, the wave conversion process shows notably different profiles for the two types of devices. Due to the contributions of ultrafast, sub-picosecond mechanisms, such as carrier heating and spectral hole burning, the pump-probe frequency can be easily tuned to the THz range. SOAs generally benefit more from sub-picosecond carrier dynamics, hence exhibiting a higher conversion efficiency (CE) in the THz range, compared to their laser diode counterparts. The discrepancy even exceeds 10 dB. In addition, laser experiments yield some differences from the amplifier ones, hence leading to a higher nonlinear CE at small detuning ranges. These results strongly improve our insight into the fundamental nonlinear properties of InAs/GaAs QD material, and contribute to the conception of novel devices for future on-chip applications in all-optical communication networks, such as signal wavelength conversion, mode-locking, and optical frequency comb generation.

Ultrasimple and Ultrafast Method of Optical Modulation by Perovskite Quantum Dot Attachment to a Graphene Surface

Optical modulation is the process of modifying the structure and elemental composition of materials so that the main optical parameters, including amplitude, frequency, and phase, are changed. Currently, much research attention has been directed toward ultrafast dynamics, but the process of modulation is often complex. To simplify the optical modulation process and improve the optical properties of perovskites for semiconductor quantum dot (QD) lasers, the process and physical mechanism underlying graphene QD ultrafast modulation of the optical properties of perovskite CsPbBr3 QDs were investigated. The typical cubic structure and square shape of CsPbBr3 QDs were characterized by transmission electron microscopy and X-ray diffraction, respectively. A luminescent peak centered near 540 nm and Stokes shift of 21.34 nm of CsPbBr3 QDs without graphene QDs were measured by absorption and photoluminescence spectroscopy. A maximum modulation shift of 133 nm and a modulation depth of 900% were achieved in CsPbBr3 with graphene. The results indicated that graphene QDs had the best modulation effect on perovskites when the drop volume was 0.05 mL. The process of ultrafast optical modulation via graphene QDs occurring within 1 ps was confirmed by the transient absorption spectrum. The modulation mechanism of graphene to perovskites is presented for guidance. This paper can be used as a reference for the optical modulation of perovskite materials.

Effect of phase conjugate coupled on routes to chaos in incoherent optical feedback semiconductor quantum dot laser

Effect of phase conjugate coupled on routes to chaos in incoherent optical feedback semiconductor quantum dot laser

Multimode Physics in the Mode Locking of Semiconductor Quantum Dot Lasers

Quantum dot lasers are an attractive option for light sources in silicon photonic integrated circuits. Thanks to the three-dimensional charge carrier confinement in quantum dots, high material gain, low noise and large temperature stability can be achieved. This paper discusses, both theoretically and experimentally, the advantages of silicon-based quantum dot lasers for passive mode-locking applications. Using a frequency domain approach, i.e., with the laser electric field described in terms of a superposition of passive cavity eigenmodes, a precise quantitative description of the conditions for frequency comb and pulse train formation is supported, along with a concise explanation of the progression to mode locking via Adler’s equation. The path to transform-limited performance is discussed and compared to the experimental beat-note spectrum and mode-locked pulse generation. A theory/experiment comparison is also used to extract the experimental group velocity dispersion, which is a key obstacle to transform-limited performance. Finally, the linewidth enhancement contribution to the group velocity dispersion is investigated. For passively mode-locked quantum dot lasers directly grown on silicon, our experimental and theoretical investigations provide a self-consistent accounting of the multimode interactions giving rise to the locking mechanism, gain saturation, mode competition and carrier-induced refractive index.

Coherent coupling of laterally coupled quantum dot lasers

Coherent coupling between two laterally coupled quantum dot semiconductor lasers based on longitudinal modes in the weak coupling regime has been investigated. Considering the effect of homogeneous and inhomogeneous broadenings, the spectral behavior of lasing modes in the coupled lasers depends on the coupling coefficient and the frequency detuning between the lasers. For cavity lengths with a minute difference and specific homogeneous broadening, full phase-locking along with single-mode operation is guaranteed provided that the coupling coefficient reaches a critical value. This result can be generalized for various cavity lengths and homogeneous broadenings covering almost all practical temperatures in the intermediate homogeneous broadening regime. The effect of coherent coupling on the emission spectrum, especially at sufficiently low temperatures at which the lasing spectrum shows broadband emission in the absence of coupling, has also been discussed. For constant cavity lengths and relatively high temperatures, onset of full phase-locking occurs at lower values of the coupling strengths, while longer cavity lengths lead to higher critical coupling strengths at a constant temperature. From a practical view, coherent coupling based on longitudinal modes has been examined in the case of a differential bias condition, which proves the electronically controllable coherent coupling of optical output signals.

Collective Coherence Resonance in Networks of Optical Neurons

The dynamical properties of an optical neuron formed by a quantum dot semiconductor laser model subjected to optical injection and optical feedback are analyzed. The parameter space spanned by the injection strength and frequency detuning of the optical injection is systematically scanned and modulations of the bifurcation boundaries that induce complex scenarios are found, which enable new opportunities to introduce the optical setup as an optical neuron. The counterintuitive behavior of coherence resonance for different setups of a single‐driven optical neuron under optical feedback is also found. Following the results, the microscopically motivated quantum dot laser rate equation model is reduced to the normal form of a saddle‐node infinite period (SNIPER) bifurcation for low injection strengths and a network of four such SNIPER systems in a globally coupled setup is studied. A new phenomenon is observed, which is called collective coherence resonance. This novel dynamical behavior is connected to the coexistence of a network‐wide SNIPER bifurcation and a change in stability for the synchronized manifold, analyzed via the master stability function.

Fast dynamics of low-frequency fluctuations in a quantum-dot laser with optical feedback.

We experimentally investigate the complex dynamics of a multi-mode quantum-dot semiconductor laser with time-delayed optical feedback. We examine a two-dimensional bifurcation diagram of the quantum-dot laser as a comprehensive dynamical map by changing the injection current and feedback strength. We found that the bifurcation diagram contains two different parameter regions of low-frequency fluctuations. The power-dropout dynamics of the low-frequency fluctuations are observed in the sub-GHz region, which is considerably faster than the conventional low-frequency fluctuations in the MHz region. Comparing the dynamics of quantum-dot laser with those of single- and multi-mode quantum-well semiconductor lasers reveals that the fast low-frequency fluctuation dynamics are unique characteristics of quantum-dot lasers with time-delayed optical feedback.

Influence of quantum-confined device fabrication on semiconductor-laser theory

Among Professor Arthur Gossard’s many contributions to crystal growth are those resulting in important improvements in the quality and performance of quantum-well and quantum-dot semiconductor lasers. In celebration of his 85th birthday, we review the development of a semiconductor laser theory that is motivated and guided, in part, by those advances. This theory combines condensed matter theory and laser physics to provide understanding at a microscopic level, i.e., in terms of electrons and holes, and their interaction with the radiation field while influenced by the lattice.

Quantum-dot semiconductor lasers with prominent relative intensity noise and spectral characteristics.

Relative intensity noise (RIN) behavior of a quantum dot laser (QDL) at free running and under optical injection locking (OIL) has been reported in detail. Considering the mutual effects of the inhomogeneous and homogeneous broadenings, different and also non-routine RIN characteristics of a QDL at low, intermediate, and high homogeneous broadening regimes have been discussed. Results demonstrate that an injection-locked quantum dot laser exhibit enhanced characteristic over free-running operation along with low-frequency noise behavior in a wide range of homogeneous broadening values. RIN reduction of about 25, 55, and 7 dB/Hz have been achieved for low, intermediate, and high values of homogeneous broadening which implies the spontaneous emission noise suppression even at low injection power. The promising impact of the OIL on side-mode suppression for the intermediate homogeneous broadening regime has also been discussed. Our results guarantee the single-mode and low-noise operation of the OIL-QDL at any homogeneous broadening value.

ABC recombination model for quantum dot laser

In this paper, we applied the ABC model in quantum dot (QD) semiconductor laser for the first time. We used a 1000μm cavity length InAsP/GaAs quantum dot laser emitting at 761nm, which was improved at Cardiff University. The ABC model is used to estimate the carrier losses that are caused by spontaneous emission and Auger recombination in semiconductor materials. It is shown that the ABC model is applicable in such lasers. The results show that the Shockley-Read-Hall (A) is 2.03 ×l09 sec−1. The radiative coefficient (B) is 2.28 ×l0−14 cm−3 .sec−1 and the Auger recombination (C) is around 8 ×l0−37 cm−6 .sec−1. The results are very close to the actual findings as measured by several different methods. Moreover, the measurement method is feasible, which can pave the path for the use of this procedure to determine the losses mechanism in semiconductor lasers.