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III-nitride quantum dot (QD) lasers have potential applications in visible light regime, yet one of its most important dynamic parameters, the linewidth enhancement factor (LEF), has been rarely studied. We studied the LEF of InGaN QD lasers with a comprehensive theory model and found that the LEF values of InGaN QD lasers can be smaller and more robust against inhomogeneous broadening than those of InGaAs QD lasers. In addition, the LEF improvement from quantum well to QD in III-nitride semiconductors is much larger than that in III-arsenide. It is believed that the large confinement energy in III-nitrides and atomic-like density of states of QDs contribute to these advantages of III-nitride QD lasers. Our results not only reveal the advantages of using III-nitride QD for high spectral purity, low-chirp laser applications, but also provide a general guideline for designing QD lasers with lower LEF values in various semiconductor materials.

On-chip lasers are a key component for the realization of silicon photonics. The performance of silicon-based quantum dot (QD) devices is approaching equivalent QDs on native substrates. To drive forward design optimization we investigated the temperature and pressure dependence of intrinsic and modulation p-doped 1.3 μm InAs dot-in-well (DWELL) laser diodes on on-axis silicon substrates for comparison with devices on GaAs substrates. The silicon-based devices demonstrated low room temperature (RT) threshold current densities ( Jth ) of 192 Acm−2 (538 Acm−2) intrinsic (p-doped). Intrinsic devices exhibited temperature stable operation from 170–200 K. Above this, Jth increased more rapidly due to increased non-radiative recombination. P-doping increased the temperature at which Jth(T) started to increase to 300 K with a temperature insensitive region close to RT, but with a higher Jth . A strong correlation was found between the temperature dependence of gain spectrum broadening and the radiative component of threshold Jrad(T) . At low temperature this is consistent with strong inhomogeneous broadening of the carrier distribution, which is more pronounced in the p-doped devices. At higher temperatures Jth increases due to homogeneous thermal broadening coupled with non-radiative recombination. Hydrostatic pressure investigations indicate that while defect-related recombination dominates, radiative and Auger recombination also contribute to Jth .

We directly compare the performance of 1.55 $\mu \text{m}$ Fabry-Perot lasers using quantum well (QW) and quantum dash gain regions. Other than the gain medium the designs were identical, grown in the same growth system, and processed at the same time. The static laser performance (light-current and spectral) were similar for both gain materials but the intensity and phase noise characteristics of the dash based lasers were significantly better. This was attributed to the self mode-locking of the dash lasers that was not observed for the QW lasers. This reduction in noise allowed individual lasing lines from the Fabry-Perot dash lasers to be used for data transmission using high order modulation schemes, with quadrature phase-shift keying (QPSK) demonstrated at a symbol rate of 32GBaud. This performance could not be achieved using the equivalent QW based laser.

We report for the first time the direct growth of quantum dot (QD) lasers with electrical pumping on 300 mm Si wafers on both a planar template and in-pocket template for in-plane photonic integration. O-band lasers with five QD layers were grown with molecular beam epitaxy (MBE) in a 300 mm reactor and then fabricated into standard Fabry–Perot ridge waveguide cavities. Edge-emitting lasers are demonstrated with high yield and reliable results ready for commercialization and scaled production, and efforts to make monolithically integrated lasing cavities grown on silicon-on-insulator (SOI) wafers vertically aligned and coupled to SiN waveguides on the same chip show the potential for 300 mm-scale Si photonic integration with in-pocket direct MBE growth.

A self-assembled quantum dot (QD) gain medium has multiple favorable material properties over conventional quantum well (QW) structures and bulk materials, including a large tolerance for material defects, reduced reflection sensitivity, nearly zero linewidth enhancement factor, low transparency current density, high temperature operation, and ultrafast gain dynamics useful for semiconductor mode-locked lasers and amplifiers. Here, we review the recent advances in the field of QD lasers and amplifiers with a focus on the direct growth on silicon (Si). Si photonics has found widespread application, particularly for high volume applications and for co-integration with CMOS electronics.

Using quantum dot (QD) structures as active material for optoelectronics was already in focus before the development of quantum well (QW) lasers and before semiconductor lasers occupied an important place in the market. The big step in reducing laser threshold conditions by substituting bulk gain materials with QWs should find a logical continuation by further reducing the dimensionality toward full 3D carrier confinement by QDs. This was predicted by theoretical considerations at the beginning of the 1980s [1], [2]. However, no practical technologies were available at that time. Top-down approaches, as originally addressed, to produce nanoscale species on very large surfaces and interface areas resulted in the accumulation of a large defect density within the active region and the domination of nonradiative carrier recombination mechanisms. Only during the early 1990s was a major breakthrough achieved with the introduction of the bottom-up approach of strain-driven, self-organized epitaxial QD growth. The first lasers were obtained in the gallium arsenide (GaAs)-based material system [3].

Optical interconnects enabled by silicon microring-based transceivers offer great potential for short-reach data communication in future high-performance computing systems. However, microring resonators are prone to process variations that harm both the energy efficiency and the yield of the fabricated transceivers. Especially in the application scenario where a batch of transceivers are fabricated for assembling multiple optical networks, how the transceivers are mixed and matched can directly impact the average energy efficiency and the yield of the networks assembled. In this study, we propose transceiver grouping for assembling communication networks from a pool of fabricated transceivers, aiming to optimize the network energy efficiency and the yield. We evaluated our grouping algorithms by wafer-scale measurement data of microring-based transceivers, as well as synthetic data generated based on an experimentally validated variation model. Our experimental results demonstrate that optimized grouping achieves significant improvement in the network energy efficiency and the yield across a wide range of network configurations, compared to a baseline strategy that randomly groups the transceivers.

In this article, a long-wave infrared InAs/GaAs sub-monolayer quantum dot quantum cascade photodetector (SML QD-QCD) grown on GaAs substrate is demonstrated. Temperature- and excitation-dependent photoluminescence measurements are used to study the optical properties of the quantum dot active region, which reveal energetically hybrid ground states between the InAs quantum dot and InGaAs quantum well due to the possible inter-mixing of In and Ga atoms during growth process. The device covers a spectral region from 6.5 to 9 μm. At 77 K, a peak responsivity of 7.5 mA/W is found at 8.3 μm (0 V) and a zero-bias differential-resistance-area ( R0A ) product of 9008 Ω·cm2 is obtained. The white noise-limited detectivity is 6.5 × 109 cm·Hz1/2/W. These results encourage the SML QD-QCD as a strong competitor for long-wave infrared imaging applications that require normal incidence and low power dissipation.

Semiconductor nanocrystals represent a promising class of solution-processable optical-gain media that can be manipulated via inexpensive, easily scalable colloidal techniques. Due to their extremely small sizes (typically

This paper investigates the impact of dislocation density and active layer structure on the degradation mechanisms of 1.3 $\mu \text{m}$ InAs Quantum Dot (QD) lasers for silicon photonics. We analyzed the optical behavior of two sets of samples, having different dislocation densities and different number of quantum dot layers in the active region. The samples were subjected to a short-term step-stress experiment and to long-term constant current operation in order to investigate the dominant degradation processes. The results indicate that: (i) the temperature stability is much higher in the devices grown on native substrate, thanks to the lower defect density; (ii) the roll-off current is considerably higher for the devices with higher number of layers, due to the lower density of carriers in the QDs; (iii) in nominal ground-state operating regime, the degradation rate is limited by the density of dislocations, that may serve as preferential paths for the diffusion of non-radiative recombination centers; (iv) at extreme injection levels and operating temperatures, the devices exhibit a blue shift of the spectral emission; possible explanations for this process are discussed in the paper.

In this letter, we report the dynamics and performance of a 1.3- $\mu \text{m}$ InAs/GaAs directly modulated quantum-dot laser (QDL) under strong feedback. At a direct modulation speed of 10 Gbps, error-free back-to-back operation of the QDL under a feedback level of −12 dB was realized. Feedback-resistant fiber transmission over 20 km under a maximum optical feedback level of −9 dB was also demonstrated with a power penalty of less than 1 dB at a bit error ratio (BER) of 10−3. The performance of the QDL was compared with directly modulated quantum-well laser (QWL) with similar parameters, showing a clear advantage in feedback resistance of QDL.

A low phase noise millimeter-wave (MMW) signal generator is proposed and experimentally demonstrated with a C-band passively Fabry-Perot (F-P) quantum dot mode-locked laser. A novel method is proposed to generate low phase noise MMW signal, which is simply based on a commercial off-the-shelf dual-driven LiNbO3 Mach-Zehnder modulator and a passively F-P quantum dot mode-locked laser. MMW signal with the frequency of 30 GHz, 45 GHz and 90 GHz respectively is obtained experimentally. Single-sideband phase noise of the 30 GHz and 45 GHz MMW signal is −112 dBc/Hz and −106 dBc/Hz at an offset of 1 kHz, respectively. The linewidth of the 30 GHz and 45 GHz MMW signal is about from 225 Hz and 239 Hz. This is considered a very simple MMW generator with a quasi-tunable broadband and ultra-low phase noise.

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.

In this work, we present an approach to modelling III-V lasers on silicon based on a travelling-wave rate equation model with sub-micrometer resolution. By allowing spatially resolved inclusion of individual dislocations along the laser cavity, our simulation results offer new insights into the physical mechanisms behind the characteristics of 980 nm In(Ga)As/GaAs quantum well (QW) and 1.3 mu quantum dot (QD) lasers grown on silicon. We identify two effects with particular importance for practical applications from studying the reduction of the local gain in carrier-depleted regions around dislocation locations and the resulting impact on threshold current increase and slope efficiency at high dislocation densities. First, a large minority carrier diffusion length is a key parameter inhibiting laser operation by enabling carrier migration into dislocations over larger areas, and secondly, increased gain in dislocation-free regions compensating for gain dips around dislocations may contribute to gain compression effects observed in directly modulated silicon-based QD lasers. We believe that this work is an important contribution in creating a better understanding of the processes limiting the capabilities of III-V lasers on silicon in order to explore suitable materials and designs for monolithic light sources for silicon photonics.

In this article, we report the demonstration of directly modulated grating-assisted microcylinder surface-emitting lasers (GAMSELs) with low threshold. Two second-order gratings are added onto the side and top of the microcylinder cavity to select a single mode with a radially polarized emission pattern and efficiently emit the mode vertically, respectively. Laser with cavity radius of 6.05 μm is demonstrated with continuous-wave lasing ranging from 1 °C to 50 °C. This radius is approaching the theoretically smallest radius for the microcylinder laser to work at O band. A low threshold of 3.6 mA at 15 °C is obtained for the GAMSEL laser. Single-mode lasing with side-mode suppression-ratio (SMSR) larger than 40 dB is also shown here. GAMSELs with different cavity radii are demonstrated as laser arrays. 3 dB direct modulation bandwidth of 12 and 14 GHz of GAMSELs with radius of about 8 and 10 μm are obtained, respectively. Besides, effects of the duty cycle of the top and side gratings, scattering losses of the cavity, gain peak of the epitaxial wafer and ion implantation are experimentally investigated.

In this study, the research on the nonlinear dynamics of semiconductor quantum dot laser with two time-delayed optical feedbacks is numerically investigated. Results show that the nonlinear dynamics behaviors of the laser are very sensitive to the rich system parameters in which both feedback strength and bias current are easily controlled to significantly influence the nonlinear dynamics including the periodic state and chaotic state. By judiciously adjusting the bias current of the laser or the feedback strength in the external cavity, period one, period doubling, quasi-period, and chaos are achieved. The feedback level-related bifurcation diagrams are analyzed in detail while fixing another feedback level at a constant or varying the bias current. In addition, the translation variables of the 0–1 test method that are clearly bounded for regular behavior and exhibit the Brownian motion for irregular phenomenon are adopted to further evaluate the periodic state and the chaotic state. These results can give insight into the quantum dot laser–based applications in various optical technologies.

Optical connectivity, which has been widely deployed in today's datacenters and high-performance computing (HPC) systems, is a disruptive technological revolution to the IT industry in the new Millennium. In our journey to debut an Exascale supercomputer, a completely new computing concept, called memory-driven computing, was innovated recently. This new computing architecture brings challenges and opportunities for novel optical interconnect solutions. Here, we first discuss our strategy to develop appropriate optical link solutions for different data traffic scenarios in memory-driven HPCs. Then, we present detailed review on recent work to demonstrate fully photonics-electronics-integrated single- and multi-wavelength directly modulated laser (DML) transmitters on silicon for the first time. Compact heterogeneous microring lasers and laser arrays were fabricated as photonic engines to work with a customized complementary metal-oxide semiconductor (CMOS) driver circuit. Microring lasers based on conventional quantum well and new quantum dot lasing medium were compared in the experiment. Thermal shunt and MOS capacitor structures were integrated into the lasers for effective thermal management and ultra low-energy tuning. It enables a controllable dense wavelength division multiplexing (DWDM) link architecture in an HPC environment. An equivalent microring laser circuit model was constructed to allow photonics-electronics co-simulation. Equalization functionality in the CMOS driver circuit proved to be critical to achieve up to 14 Gb/s direct modulation with 6 dB extinction ratio. Finally, the on-going and future work is discussed towards more robust, higher speed, and more energy efficient DML transmitters.

Photonic integrated circuits (PICs) have enabled numerous high performance, energy efficient, and compact technologies for optical communications, sensing, and metrology. One of the biggest challenges in scaling PICs comes from the parasitic reflections that feed light back into the laser source. These reflections increase noise and may cause laser destabilization. To avoid parasitic reflections, expensive and bulky optical isolators have been placed between the laser and the rest of the PIC leading to large increases in device footprint for on-chip integration schemes and significant increases in packaging complexity and cost for lasers co-packaged with passive PICs. This review article reports new findings on epitaxial quantum dot lasers on silicon and studies both theoretically and experimentally the connection between the material properties and the ultra-low reflection sensitivity that is achieved. Our results show that such quantum dot lasers on silicon exhibit much lower linewidth enhancement factors than any quantum well lasers. Together with the large damping factor, we show that the quantum dot gain medium is fundamentally dependent on dot uniformity, but through careful optimization, even epitaxial lasers on silicon can operate without an optical isolator, which is of paramount importance for the future high-speed silicon photonic systems.

We measure the FM noise power spectral density of quantum-dot mode-locked lasers (QD-MLLs) and compare this to their measured linewidths as predictors of performance in a digital coherent system. We explain our observations in terms of the non-Lorentzian line shape of the source wherein linewidth is determined by the low frequency part of its FM noise. Investigation of system performance with simulations based on the measured phase sequences and back-to-back coherent transmission experiments show that QD-MLLs with linewidths of several megahertz can have comparable performance to that of a laser with only a few hundreds of kilohertz of Lorentzian linewidth, due to the non-white part of their FM noise. We show that spectral linewidths of lasers with similar spectral properties can underestimate their performance in coherent systems, regardless of the linewidth measurement technique used. We propose a “ Lorentzian-equivalent linewidth ” measure to characterize lasers with non-white FM noise and to estimate their impact in digital coherent optical systems. This measure is obtained from phase variations at frequencies higher than typical frequencies often used to characterize lasers with white FM noise and comparable to the system baud. The proposed measure is shown to be a better predictor of system performance than the measured linewidth, for lasers with non-white FM noise. The impact of non-white FM noise on the optimization of carrier phase recovery and system performance is also discussed.

This work investigates the degradation processes affecting the long-term reliability of 1.3 μm InAs quantum-dot lasers epitaxially grown on silicon. By submitting laser samples to constant-current stress, we were able to identify the physical mechanisms responsible for the optical degradation. More specifically, the samples (i) exhibited a gradual increase in threshold current, well correlated with (ii) a decrease in sub-threshold emission, and (iii) a decrease in slope efficiency. These variations were found to be compatible with a diffusion process involving the propagation of defects toward the active region of the device and the subsequent decrease in injection efficiency. This hypothesis was also supported by the increase in the defect-related current conduction components exhibited by the electrical characteristics, and highlights the role of defects in the gradual degradation of InAs quantum dot laser diodes. Electroluminescence measurements were used to provide further insight in the degradation process.

Dynamics of a multimode quantum dot laser with polarization-rotated optical feedback is investigated in a wide range of bias current. The results reveal that the laser is more sensitive to optical feedback when the polarization of feedback beam is rotated a large angle from the original polarization, which is different from the results in DFB lasers. Anticorrelated fluctuations between orthogonal polarizations are observed in a certain range of selected polarizations. Accordingly, dynamics in the total power can be weaker than that in a selected polarization. The anticorrelated polarization dynamics may be related to different polarizations of longitudinal modes.

This paper reviews optical injection locking (OIL) of semiconductor lasers and its application in optical communications and signal processing. Despite complex OIL dynamics, we attempt to explain the operational principle and main features of the OIL in an intuitive way, aiming at a wide understanding of the OIL phenomenon and its associated techniques in the optic and photonic communities. We review and compare different control techniques that enable robust OIL in practical systems. The applications are reviewed with a focus on new developments in the past decade, under the categories of ‘High Speed Directly Modulated Lasers’ and ‘Optical Carrier Recovery’. Finally, we draw our vision for future research directions.

We report high-performance broad-area eight-layer InAs/GaAs quantum-dot lasers (QDLs) emitting at 1.3 μm in the pulse and continuous-wave (CW) operations. Operational characteristics of the fabricated QDLs, including the emission wavelength, output power, threshold-current density, differential quantum efficiency, and characteristic temperature, are investigated at different temperatures. For as-cleaved facets of 100 μm wide and 1 mm cavity-length device, an output power of 100 mW is achieved at 1 kHz with 5% duty cycle and 49 mW in the CW operation. The device exhibits a threshold-current density of 56 A/cm2 at room temperature in both the operating modes and increases to 71 and 80 A/cm2 the in the pulse and CW modes, respectively, at 343 K. Over a temperature range of 298K to 343 K, we calculate the threshold characteristic temperature of 166K and 119K and slope-efficiency characteristic temperature of 2061K and 408K in the pulse and CW modes, respectively. The laser exhibits differential quantum efficiency of 41% and 32% in the pulse and CW mode, respectively. We observed that the device exhibited negligible dependence over a temperature range of 298K to 343 K.

$p$ -type modulation doping of the quantum dot active region is known to improve high temperature and dynamic performance of quantum dot lasers. These improvements are critical to realizing commercially relevant quantum dot devices on silicon and are shown to enable continuous wave operation over 100°C, nearly complete insensitivity to optical feedback, and orders of magnitude improvement in device reliability relative to unintentionally doped active regions. Also described is a spectrally resolved analysis of the effect of p-modulation doping on the optical gain revealing anomalous behavior that explains the high characteristic temperatures commonly observed in literature for similar devices on native substrate.

Owing to the excellent properties of perovskite quantum dots (QDs), such as an easy synthesis process, high photoluminescence quantum yields, high defect tolerance, and tunable bandgap with different elements, laser actions have been widely conducted. Over the past few years, several approaches have been used for successfully creating perovskite QD lasers. In this review, we summarize the progress of perovskite QD lasers from the aspects of laser theory, characteristics and applications of QD lasers, advantages of perovskite materials for lasers, factors influencing the QD laser threshold, two‐photon pumped QD lasers, and perovskite QD laser stability. At the same time, aiming at existing problems, possible solutions and prospects are presented.

A three-fold reduction of threshold current, with a minimum threshold current density of 286 A/cm 2 , a maximum operating temperature of 80 °C, and a maximum 3 dB bandwidth of 5.8 GHz was achieved for 1.3 μm InAs quantum dot lasers on patterned, on-axis (001) Si. This was enabled by the reduced threading dislocation density (from 7×10 7 to 3×10 6 cm −2 ), and optimized probe design. The patterned Si produced antiphase domain free material in the coalesced GaAs buffer layer with reduced misfit/threading dislocation nucleation, without the use of Ge/GaP buffers or substrate miscut. Utilizing aspect ratio trapping, cyclic thermal annealing, and dislocation filter layers, high quality III-V on Si devices were grown, demonstrating the compelling advantages of this patterned Si template for a monolithic Si photonics integration platform.

Free-running quantum cascade lasers (QCLs) show a natural tendency to operate in the multimode regime as a result of both spatial and spectral hole burning. While multimode operation by itself is far from unusual, what distinguishes QCLs from other lasers is that the phases of the individual modes in them can be locked in the absence of any additional intracavity elements, thus forming frequency combs (FCs) that have many practical applications. Unlike typical FCs produced in mode-locked lasers or microcavities, the temporal shape of a QCL FC is not a short pulse but rather a combination of frequency and (to a lesser extent) amplitude modulated signals, the origin of which is not obvious. In this paper, we develop a theory aimed at explicating the most recent experimental measurements of temporal characteristics of QCL FCs. We identify spatial hole burning as the root cause of frequency modulation and show that, in addition to previously analyzed rapid, pseudo-random frequency modulation, the experimentally observed long linearly chirped signal can also alleviate spatial hole burning efficiently. We find that in the absence of spectral hole burning, a linearly chirped regime has the lowest threshold. Furthermore, we show that for relatively weak frequency modulation, amplitude modulation should also arise as confirmed experimentally. The result of this paper is a first step toward reliably engineering FCs with specified characteristics in mid IR and THz regions.

The linewidth enhancement factor ( $\alpha _\mathrm{H}$ ) is an important parameter for semiconductor lasers. In this paper, we investigate, both theoretically and experimentally, the key parameters that affect $\alpha _\mathrm{H}$ of InAs/GaAs quantum dot lasers. Both dot uniformity and doping density are found to be critical in achieving small $\alpha _\mathrm{H}$ in quantum dot lasers. The prospects for quantum dot lasers in isolator-free and narrow linewidth applications are also discussed.

This paper investigates the intensity noise and pulse oscillation characteristics of an InAs/GaAs quantum dot laser epitaxially grown on germanium. We show that the relative intensity noise of the free-running laser generally decreases with increasing pump current, and the minimum value reaches down to about $-$ 126 dB/Hz. The intensity noise is hardly affected by the optical feedback, unless there is a resonance or pulse oscillation in the noise spectrum. The laser pumped at a high current is more sensitive to the optical feedback. Interestingly, it is found that the free-running Ge-based quantum dot laser generates self-sustained pulse oscillations with one period or two periods upon the pump current, without incorporating saturable absorbers. This behavior is valuable for both self-generation of photonic microwaves and for understanding nonlinear dynamics of semiconductor lasers.

Initial age-related degradation mechanisms for InAs quantum dot lasers grown on silicon substrates emitting at 1.3 μ m are investigated. The rate of degradation is observed to increase for devices operated at higher carrier densities and is therefore dependent on gain requirement or cavity length. While carrier localization in quantum dots minimizes degradation, an increase in the number of defects in the early stages of aging can increase the internal optical-loss that can initiate rapid degradation of laser performance due to the rise in threshold carrier density. Population of the two-dimensional states is considered the major factor for determining the rate of degradation, which can be significant for lasers requiring high threshold carrier densities. This is demonstrated by operating lasers of different cavity lengths with a constant current and measuring the change in threshold current at regular intervals. A segmented-contact device, which can be used to measure the modal absorption and also operate as a laser, is used to determine how the internal optical-loss changes in the early stages of degradation. Structures grown on silicon show an increase in internal optical loss, whereas the same structure grown on GaAs shows no signs of increase in internal optical loss when operated under the same conditions.

Dual-state emission is a common and important phenomenon which takes place in semiconductor Quantum Dot Lasers at different temperature and operating conditions usually investigated from microscopic carrier interaction modeling or even rate-equations based approaches. In this study, we revisit the topic, but the investigation is here performed from a system identification perspective; we built black-box models based on artificial neural networks approach, using the Multilayer Perceptron, the Extreme Learning Machine and a hybrid Echo State Network - Extreme Learning Machine. As a case study, we focused on switch-on transient and its prediction. The study revealed the model was able to separate and to predict, from the solely total power, without using any QDL design parameters, the optical power around the ground state and first excited state lasing lines of InAs/InGaAs quantum dot laser. The error performance was low as a RMSE of 2.81 μW and MAPE of 0.50% with processing time (training and testing time) of 15.27 s, enabling the alternative model to be used in optical filtering instrumentation as low-resolution and low-cost filters for applications in which it is not economically viable to use a spectrum analyzer, which can be replaced by a simple optical power meter.

Quantum dot (QD) laser as a light source for silicon optical integration has attracted great research attention because of the strategic vision of optical interconnection. In this paper, the communication band InAs QD ridge waveguide lasers were fabricated on GaAs-on-insulator (GaAsOI) substrate by combining ion-slicing technique and molecular beam epitaxy (MBE) growth. On the foundation of optimizing surface treatment processes, the InAs/In0.13Ga0.87As/GaAs dot-in-well (DWELL) lasers monolithically grown on a GaAsOI substrate were realized under pulsed operation at 20 °C. The static device measurements reveal comparable performance in terms of threshold current density, slope efficiency and output power between the QD lasers on GaAsOI and GaAs substrates. This work shows great potential to fabricate highly integrated light source on Si for photonic integrated circuits.

The realization of monolithic integration of a stable III–V laser on a standard silicon-on-insulator (SOI) substrate has been regarded as a challenging technology for silicon-based photonic integration circuits (PICs). Here, we successfully demonstrated the electrically pumped P-doped 1300 nm InAs/GaAs quantum dot (QD) laser epitaxially grown on {111}-faceted SOI hollow substrates. These III–V QD lasers, which are epitaxially grown on an SOI substrate, generally exhibit strong thermal accumulation due to the oxide layer underneath. By applying a double-side heat dissipation design, the maximum operation temperature of the SOI-based InAs/GaAs QD laser under a continuous-wave (CW) operation mode is ramped up to 35°C from 20°C. Moreover, the thermal profile simulation of three different structures has also been carried out to show the effectiveness of the top heat sink design in order to improve laser performance. An integrated thermal shunt design is proposed to improve heat dissipation without using the external top heat sink. The successful realization of room-temperature SOI-based InAs/GaAs QD lasers pave a viable way for integrating light sources in PICs.

Based on the three-energy level exciton model of the quantum dot lasers (QDLs), the nonlinear dynamics of the sole ground-state emitting QDL (GS-QDL) under external optical injection is numerically studied. The results show that the GS-QDL can generate period-one, period-two, multi-period, chaotic pulse and injection locking states under suitable injection parameters. By analyzing the distribution of these dynamic states in the injection parameter space, it is found that the period-one state and injection locking state occupy a large area, but the region of the complex dynamics is relatively small. Moreover, the complexity of the chaotic signals generated by the GS-QDL is quantified by the permutation entropy calculation. The results show that the complexity of the chaotic signals is less than 0.90, which indicates that the GS-QDL is low sensitivity to external optical injection. The GS-QDL can be used in isolator-free photonic integrated circuits.

We propose a multilayer silicon nitride (SiN) -on-silicon photonic integrated circuit (PIC) platform with a monolithic laser at the C-band. A tapered edge coupler and a meta-structure-based interlayer directional coupler in the platform were designed to realize low-loss broadband laser-to-chip 3D coupling with small footprint. The coupling length of the interlayer directional coupler and the gap between different SiN layers were optimized as 12.7 µm and 1.4 µm. We measured the 1-dB-drop optical operation bandwidth of greater than 76 nm and the coupling loss of 6.1 ± 0.1 dB at 1550 nm for the interlayer directional coupler. The hybrid integration was demonstrated as a proof of concept for monolithic integration of light sources. The butt-coupling loss of 3.7 ± 0.1 dB between an on-chip DFB laser and a SiN edge coupler at 1549.48 nm was achieved. This approach opens the possibility of employing monolithic laser in the silicon photonics platform.

With exponential growth in data traffic and limitations of Moore’s Law, electronic integrated circuits have reached a bottleneck period. Photonic Integrated Circuits (PICs) are seemed as candidate for solving the problem of data transmission. Moreover, robust laser sources are significant building block for PICs design. Here, we demonstrate several InAs/GaAs quantum dot microcavity lasers monolithically grown on planar on-axis Si (001) substrates, including microdisk cavity [1], 2D Photonic Crystal with L3 defects cavity [2], 1D Photonic Crystal nanobeam cavity, bandedge Photonic Crystal cavity, bound states in the continuum (BIC) cavity, etc.

For the first time, RIN reduction in gain-switched quantum dot laser is demonstrated with an optical beam illumination to the excited state. It is also found that pulses having a width of 27–29 ps with a high peak power are generated under the noise.

Regrown quantum-dot distributed feedback lasers on Si demonstrate record performance, with a threshold current of 10 mA, an intrinsic linewidth of 41.2 kHz, a side-mode suppression ratio of 57.5 dB, and a maximum power of 11.7 mW.

InAs quantum dot lasers on silicon using misfit dislocation trapping layers show 400-fold improvement in lifetime at 80°C (failure criterion: 50% initial peak power). Trapped misfit segments show no evidence of recombination enhanced dislocation climb, leading to an order of magnitude reduction in its extent.

For the first time, with an optical beam illumination, gain-switched short pulses with a width of 25–40 ps with a high peak power are generated owing to excited state transitions, and the change in the laser parameters does not affect the output pulses strongly.

We demonstrate the superior emission properties of a red-emitting self-assembled quantum dot microsphere laser made from a blend of green and red bandgap CdS x Se 1-x / ZnS quantum dots. The addition of the higher bandgap material reduces self-absorption and improves the Q-factor.

Direct epitaxy of InP quantum dot (QD) lasers on silicon (Si) provides an on-chip red laser source for integrated Si photonics with different applications. Here, we demonstrate the first, to the best of our knowledge, InP QD lasers directly grown on (001) Si. Combining highly emissive InP QDs and a GaAs/Si template with low defect density, continuous-wave (CW) lasing of micro-disk lasers (MDLs) on Si is achieved at room temperature. The lowest threshold of MDLs on Si is ∼ 500 n W , without considering the micro-disk surface absorption efficiency of the pump power. The MDLs grown on the native GaAs substrate with the same growth and fabrication process are compared using statistical data analysis. Similar material characterization results and device performances on these two substrates further confirm the performance of QD lasers on Si. This demonstration paves the way for future realization of integrated photonic circuits with red and near-infrared (NIR) lasers on Si.

Quantum dots (QDs) are a revolution in the field of photoelectric and have a crucial potential for future applications as a color converter in micro/mini- LEDs. However, the reported QD converter efficiency (-20-40%) has not reached the level on par with that of the conventional phosphor color converters (~40-60%). In this study, we fabricate the QD nanowires (NWs) templated in the nanoporous anodic aluminum oxide (AAO) substrate using a combination of inkjet printing and vacuum-deposition. Owing to the light couple and waveguide effect of the nanopores cavity structure, we demonstrate a 1.25-fold enhancement in the luminous flux and a 2.04-fold increase in the photoluminescence (PL) intensity compared with the traditional QD planar converter. Furthermore, the stability test showed a 2.34 times improvement in lifetime resulting from the heat dissipation and moisture protection of the nanopores. The inkjet printing fabrication strategy combined with the nanostructure provides new insights for mass-produce high-quality QD NWs, which is promising for modern lighting applications in the micro/mini-lighting-emitting diodes (LEDs).

Dual-state emission is an phenomenon which takes place in Quantum Dot Lasers at different temperature and operating conditions. In this study, we investigate that issue from a nonlinear regression model based on Extreme Learning Machine, which revealed to be able to predict the spectrally resolved transient response of InAs/InGaAs quantum dot laser with error performance as low as 0.54%.

For the first time gain-switched short pulse generation with a width of 25-40 ps from excited state is demonstrated applying an external optical Gaussian beam to the excited state of InAs-InP-(113)B quantum dot laser.

We discuss the integration of quantum dashes (QDashes) into laser simulations using Crosslight Pics3D, outlining the approach for developing a model featuring asymmetrical active regions. The importance of including wetting layers to accurately represent carrier transport is investigated using results obtained for an InAs/InP QDash laser. While leakage current across the active region is unaffected by the absence of wetting layers, their presence enhances Auger recombination losses in the active region, leading to lower overall device efficiencies.

InAlGaAs/GaAs quantum dots (QDs) are grown by molecular beam epitaxy and subsequently characterized to achieve emission $\lt 1\ \mu$m. Growth parameters are optimized to grow a new generation of homogeneous quaternary QDs with a PL FWHM of $\sim 60\ \mathrm{meV}$ and a surface density of $\gt10^{10} \mathrm{~cm}^{-2}$.