Semiconductor Laser System Research Articles

Semiconductor laser systems excited by multiplicative Ornstein-Uhlenbeck noise and additive sine-Wiener noise in relation to real and imaginary parts.

In this paper we study a semiconductor laser system excited by multiplicative Ornstein-Uhlenbeck (OU) noise and additive sine-Wiener (SW) noise with a related real part and imaginary part. The two-dimensional Langevin equation(LE) with cross-correlating complex OU noise and complex SW noise is equivalent to the six-dimensional LE. Based on functional methods and spatial dimension extension methods, the six-dimensional Fokker-Planck equation(FPE) is achieved. Through Taylor expansion approximation and linear transformation, the dimensionality of FPE is reduced, and the exact expression of the probability distribution (SPD) in steady state is obtained. The impacts of noise parameters on laser intensity on SPD are further analyzed. Moreover, based on the reduced FPE, the information entropy of the system is obtained. This calculation is useful for us to understand further the influence of system parameters and noise correlation coefficient on the system. The main work lies in obtaining an alternative method for deriving a FPE corresponding to the two-dimensional stochastic semiconductor laser model, which is more applicable than methods in previous literature. An equivalent expression for cross-correlated OU noise and cross-correlated SW noise as well as a method for approximate solutions of a high-dimensional FPE are also provided.

Characterizing Extreme Events in a Fabry–Perot Laser with Optical Feedback

The study of extreme events (EEs) in photonics has expanded significantly due to straightforward implementation conditions. EEs have not been discussed systematically, to the best of our knowledge, in the chaotic dynamics of a Fabry–Perot laser with optical feedback, so we address this in the current contribution. Herein, we not only find EEs in all modes but also divide the EEs in total output into two categories for further discussion. The two types of EEs have similar statistical features to conventional rogue waves. The occurrence probability of EEs undergoes a saturation effect as the feedback strength increases. Additionally, we analyze the influence of feedback strength, feedback delay, and pump current on the probability of EEs defined by two criteria of EEs and find similar trends. We hope that this work contributes to a deep understanding and serves as inspiration for further research into various multimode semiconductor laser systems.

Optimization of chaotic light output in semiconductor laser systems based on multi-objective optimization algorithm.

Aiming at the weak performance of chaotic light output in semiconductor laser systems, the study designed a power control algorithm for semiconductor laser drive systems based on linear self-disturbance rejection control. Then the optimization parameters and scope were determined, and multi-objective optimization and direction preference algorithms were introduced. A chaotic optical performance optimization model based on improved multi-objective genetic algorithm was constructed using adaptive functions as evaluation indicators. These results confirmed that the larger the bandwidth of the controller, the faster the response speed of the resonant converter, but the stability was poor. When the input voltage underwent a sudden change, the current ripple coefficient of the PID algorithm was 0.55%. The linear active disturbance rejection control algorithm could ensure that the voltage and current maintained at the set values, and the output current of the algorithm was more stable when the load underwent sudden changes. The directional preference algorithm could further provide more valuable solutions on the basis of adaptive genetic algorithms. When the peak value of the autocorrelation function was equal to 0.2, the delay characteristics of chaotic light were effectively suppressed, having strong signal bandwidth and complexity. In summary, the constructed model has good application effects in optimizing chaotic optical performance and has certain positive significance for communication security.

Enhanced extreme events in three cascade-coupled semiconductor lasers

Extreme events (EEs) are rare and unpredictable, as have been observed in nature. Up to now, manipulating EEs has remained a challenge. Here, we experimentally observe the enhancement of EEs in a three cascade-coupled semiconductor laser system. Specifically, a continuous-wave optical injection semiconductor laser acts as the chaotic source with rare EEs, which is subsequently injected into a second laser for increasing the number of EEs. Interestingly, we find that the number and region size of EEs can be further enhanced by sequentially injecting into a third laser, i.e., a cascade-injection structure. Our experimental observations are in good agreement with the numerical results, which indicate that EEs can be significantly enhanced in wide injection parameter space due to the cascade-injection effect. Furthermore, our simulations show that the evoluation of the regions with enhanced EEs may be associated with the noise considered.

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).

Modeling and Simulation of a Cascaded Polarization-coupled System of Broad-area Semiconductor Lasers

Modeling and Simulation of a Cascaded Polarization-coupled System of Broad-area Semiconductor Lasers

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.

Stochastic dynamics of a semiconductor laser with delayed optoelectronic feedback and noise

Semiconductor lasers(SLs), versatile tools in communication, medicine, and scientific research, demand close examination of their dynamic behavior. With their unique geometric forms and diminutive sizes, these lasers possess a heightened sensitivity to noise. In this paper, we delve into time-delay semiconductor laser systems, noise included, honing in on time-delays’ effects on noisy laser equations. Carrier density (N) and laser intensity (I) constitute the core parameters that define the performance of these lasers, and we scrutinize their dynamic trajectories. A cutting-edge method fusing stochastic center manifold theory with the stochastic averaging method enables us to probe the stochastic dynamical attributes of semiconductor laser equations. We uncover that the time-delay parameter (τ 1) produces varied consequences on the laser system’s stability under both positive and negative optical feedback conditions. The negative feedback typically bolsters laser performance, fostering increased stability, whereas the positive counterpart could incite instability. By deftly managing the time-delay parameter, one can fine-tune the dynamic performance of semiconductor lasers, mitigating output power fluctuations and tightening linewidths, thereby augmenting stability and spectral purity. Moreover, in the realm of positive optical feedback scenarios, adroitly modifying the time-delay parameter can quell instability to a degree, paving the way for a novel regulatory approach to optimize laser performance. This lays the groundwork for further enhancement of semiconductor laser performance, as well as curbing the detrimental effects of noise on their operation.

Laser isotope separation to study for the neutrino-less double beta decay of 48Ca

The laser isotope separation (LIS) system is being developed for the study of neutrino-less double beta decay of 48Ca. A proof-of-principle experiment has been successfully conducted, and development of a mass production (∼1 mol/year) system is currently underway. For stable and efficient production, we are preparing an atomic beam system capable of producing a well-collimated beam with sufficient flux and a high-power semiconductor laser system with stable frequency over a long period of time.

Effect of laser radiation on the growth of Rhodotorula mucilaginosa isolated from rumin fluid of cows in the Nineveh, Iraq.

The fungi Rhodotorula species are widespread airborne contaminants and are thought to be natural occupants of human skin, lungs, urine, and feces. Therefore, Rhodotorula mucilaginosa, Rhodotorula minuta, and Rhodotorula glutinis are three of the most prevalent species. This study aims to isolate R. mucilaginosa from the rumen fluid of cows in the province of Mosul and to determine how laser light irradiation affects the growth and morphological traits of these Fungi. From the rumen fluid of AL-Restaki and AL-Karadi of cows, the R. mucilaginosa was isolated. Using the traditional approach and the ID-Yst card system Vitek 2. A semiconductor laser system with a power of 50 mW and a wavelength of 450 nm was used in the experiment to evaluate the light laser irradiation effects on the culture growth of R. mucilaginosa directly under two light irradiation conditions of 30 and 60 minutes. According to traditional methods and the ID-Yst card system Vitek 2, R. mucilaginosa predominated 7/30 (23.3%), and these strains effectively grow on medium sabouraued dextrose agar as evidenced by the carotenoid pigments that gave their colonies a salmon-pink to coral-red. Compared with a control group where no laser was used, the impact of light laser irradiation was assessed 24 hours after the irradiation using biomass (dry weight measuring yeast cell content in suspension) and microscopic analysis using Gram stain. Microscopic examinations showed the irregular shape of the cells linked to one another. The irradiated subculture of on Sabouraued dextrose agar and incubation at 37°C for 3 days demonstrated inhibited growth in 4/7 (57.1%) isolates. In addition, there was no discernible difference vertically at p < 0.05 between the control group and the R. mucilaginosa biomass concentration under light irradiation circumstances (30 and 60 minutes). This study proved that R. mucilaginosa is found in the rumen fluid of cows. Also, the isolated R. mucilaginosa displayed sensitivity to laser irradiation lights, revealing the more significant topographical alterations of the cell structure that had happened, the irregular shape of the cells, and how they were connected as a result of evolution.

Recent Advances in Optical Injection Locking for Visible Light Communication Applications

The introduction of visible light communication (VLC) technology could increase the capacity of existing wireless communication systems towards 6G networks. In practice, VLC can make good use of lighting system infrastructures to transmit data using light fidelity (Li-Fi). The use of semiconductor light sources, including light-emitting diodes (LEDs) and laser diodes (LDs) are essential to VLC technology because these devices are energy-efficient and have long lifespans. To achieve high-speed VLC links, various technologies have been utilized, including injection locking. Optical injection locking (OIL) is an optical frequency and phase synchronization technique that has been implemented in semiconductor laser systems for performance enhancement. High-performance optoelectronic devices with narrow linewidth, wide tunable emission, large modulation bandwidth and high data transmission rates are desired for advanced VLC. Thus, the features of OIL could be promising for building high-performance VLC systems. In this paper, we present a comprehensive review of the implementation of the injection-locking technique in optical communication systems. The enhancement of characteristics through OIL is elucidated. The applications of OIL in VLC systems are discussed. The prospects of OIL for future VLC systems are evaluated.

Comparison of Calculation Methods for Chaotic Laser in Semiconductor Laser System

Comparison of Calculation Methods for Chaotic Laser in Semiconductor Laser System

Evolution of extreme events in chaotic light-injected semiconductor lasers

&lt;sec&gt;Rare ultrahigh pulses, classified as rogue waves (RWs), are inevitable and catastrophic in many different systems. Considering the damage they may produce, it is meaningful to understand the formation mechanism of these pulses and, if possible, control them. However, the rarity of RW and the difficulty in implementing the experiment are major limitations to understanding their formation. In 2007, Solli et al. (Solli D R, Ropers C, Koonath P, Jalali B &lt;ext-link ext-link-type="uri" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://www.nature.com/articles/nature06402"&gt;2007 &lt;i&gt;Nature&lt;/i&gt; &lt;b&gt;450&lt;/b&gt; 1054&lt;/ext-link&gt;) introduced the concept of optical RW, i.e. extreme event (EE) by comparing the appearance of oceanic RWs with the propagation of light fields in optical fibers. After that, the research of EEs entered into a flourishing period and different optical systems were proposed to analyze the generation and origin of EEs. Linear system is one of the most widely studied EE systems, such as linear light propagation in glass fibers, random media, and linear interference models. In addition to the linear systems mentioned above, efforts have also been made to produce nonlinear systems of EEs, such as microstructure fibers and tapered gradient exponential nonlinear fibers. In these nonlinear systems, the formation mechanism of EE is studied by using the nonlinear Schrödinger equation. Recently, the EEs in semiconductor laser systems have received a great deal of attention. On the one hand, semiconductor lasers with rich dynamic properties provide a cheap and controllable platform for understanding and predicting EE. The behavior of EE, on the other hand, is a powerful tool for understanding the fundamental mechanism of different laser systems.&lt;/sec&gt;&lt;sec&gt;In this work, based on the EEs generated in a semiconductor laser with phase-conjugate optical feedback (the master laser, ML), we inject its output into another free-running semiconductor laser (the slave laser, SL) and discuss the evolution of EEs in the system by numerical simulation. Herein, we analyze the influence of injection parameters on EEs through the two-dimensional maps of the relative number of EEs in the injection-parameter space. It can be concluded that in an area of high correlation, the relative number of EEs in SL tends to be a stationary value close to that in ML, while it may be enhanced in some weakly correlated regions. The results demonstrate the possibility of controlling EEs by optical injection, which is beneficial to optimizing the performance of chaotic laser systems or expanding their application scope.&lt;/sec&gt;

Extreme events in two laterally-coupled semiconductor lasers.

Rogue waves (RWs) are extreme and rare waves that emerge unexpectedly in many natural systems and their formation mechanism and prediction have been extensively studied. Here, we numerically demonstrate the appearance of extreme events (EEs) for the first time, to the best of our knowledge, in the chaotic regimes of a two-element coupled semiconductor laser array. Based on coupled-mode theory, we characterize the occurrence of EEs by calculating the probability distribution, which confirms the RW-type feature of the intensity pulses, i.e., non-Gaussian distribution. Combining with the results of the 0-1 test for chaos, we confirm that EEs originate from deterministic nonlinearities in coupled semiconductor laser systems. We show that EEs can be predicted with a long anticipation time. Furthermore, simulation results manifest that the occurrence probability of EEs can be flexibly tuned by tailoring the coupling parameter space. With the help of two-dimension maps, the effects of key parameters, i.e., the waveguide structure and the pump level, on the formation of EEs are discussed systematically. This work provides a new platform for the research of EEs in a highly integrated structure and opens up a novel investigation field for coupled semiconductor laser arrays.

A Laser-Induced Photoelectrochemical Sensor for Natural Sweat Cu2+ Detection

Tracking fluctuations in the Cu2+ level in sweat is meaningful for non-invasive and real-time assessment of Cu2+-abnormality-related diseases and provides important diagnostic information. However, the user-unfriendly ways to obtain sweat and sweat biofouling have limited the development of this field. Herein, we exploit a highly sensitive photoelectrochemical (PEC) sensor as a detection method, a powerful laser engraving technique for the large-scale fabrication of laser-induced graphene and In-doped CdS (LIG-In-CdS) photoelectrodes, and a hydrophilic porous polyvinyl alcohol (PVA) hydrogel for natural sweat collection for fingertip touch sweat Cu2+ monitoring. The proposed sensor has several very attractive features: (i) the LIG-In-CdS photoelectrode with high photoelectric conversion efficiency can be produced by a cheap 450 nm semiconductor laser system; (ii) the sensor performs Cu2+ detection with a wide linear range of 1.28 ng/mL~5.12 μg/mL and good selectivity; (iii) the PVA hydrogel possesses an excellent antifouling effect ability and a rapid natural sweat collection ability; and (iv) the sensor exhibits feasibility and good reliability for PEC sensing of sweat Cu2+. Thus, these advantages endow the proposed method with a great deal of potential for smart monitoring of heavy metals in sweat in the future.

Design of High Precision Semiconductor Laser System

In PCR technology, the suitability and stability of the light source used to excite fluorescence is particularly important. Semiconductor laser not only plays an important role in medical, science and technology, aerospace, transportation, communications and other fields, but also brings great changes to society. In this paper, the research background and the overall design architecture of the laser are described first, and then the circuit design of the key modules of the system is described in detail, the optical control closed-loop feedback system ensures the stability of laser drive current, and the temperature control closed-loop and PID algorithm reduce the adverse effects of temperature on laser power. At the same time, the sparrow search algorithm is used to optimize the three parameters of PID, the simulation results and test data show that: The whole design fully meets the needs of the application scene.

Extreme events in a broad-area semiconductor laser with coherent injection

Spatiotemporal extreme events are interesting phenomena, both from a fundamental point of view, as manifestations of complexity in dynamical systems, and for their possible applications in different research fields. Here, we present some recent results for extreme events in spatially extended semiconductor laser systems (broad-area vertical cavity surface-emitting lasers) with coherent injection. We study the statistics of spatiotemporal intensity peaks occurring in the transverse $(x,y)$ section of the field perpendicular to the light propagation direction and identify regions in the parameter space where extreme events are more likely to occur. Searching for precursors of these phenomena, we concentrate, on the one hand, on the spatiotemporal dynamics of the field phase and, in particular, on the presence of optical vortices in the vicinity of an extreme event. On the other hand, we focus on the laser gain dynamics and the phase-space trajectories of the system close to the occurrence of an extreme event. Both these complementary approaches are successful and allow us to shed some light on potential prediction strategies.

Chaotic characteristics of output light from semiconductor laser with self-chaotic phase modulation and optical feedback

&lt;sec&gt;Distributed feedback semiconductor lasers (DFB-SLs) are the class B lasers, and would output chaotic laser under the external disturbances, such as external optical feedback and optical injection. Chaotic laser are widely used in many fields, including optical fiber sensing, chaotic laser secure communication, and better entropy sources for generating high-speed random number. However, the chaotic laser outputted from the semiconductor lasers with external cavity optical feedback produces a time delay signature (TDS) , which limits the applications of chaotic laser. On the other hand, the bandwidth (BW) of chaotic carrier signal plays the important role in determining the transmission rate of information signal. Therefore, the TDS and BW are two important parameters that will affect chaotic laser’s applications, and they are usually used to describe the chaos characteristics of chaotic laser.&lt;/sec&gt;&lt;sec&gt;In this paper, we present a new scheme used to describe the TDS and investigate the BW of chaotic laser from semiconductor laser. For this scheme, the output laser from a DFB-SL with external single optical feedback is injected in double ways into another DFB-SL with phase modulation optical feedback by self chaos light. Thus they form a semiconductor laser system with external double optical injection and phase modulation optical feedback by self chaos light (SL-EDOI-PMOFBSCL). We investigate numerically the influences of the system parameters on TDS, such as the injection coefficient and feedback coefficient. Then the suppression effects on TDS are contrasted and analyzed with two other systems, that is to say, the semiconductor laser with external double optical injection and optical feedback (SL-EDOI-OF) and the semiconductor laser with external single optical injection and phase modulation optical feedback by self chaos light (SL-ESOI-PMOFBSCL). The results indicate that the proposed scheme in this work has the better suppression effect on TDS. Then the BW of the chaotic laser is investigated under the parameters conditions of effectively suppressing TDS. The simulation results show that the scheme proposed in this work can enhance the BW of chaotic laser by appropriately selecting the parametric values, and the maximum BW value of the obtained chaotic laser reaches about 16 GHz.&lt;/sec&gt;

SIGNAL PROCESSING AND CYBERSECURITY IN SOME CHAOTIC OPTICAL COMMUNICTAION SYSTEMS

A chaos –geometric approach to investigation of complex chaotic dynamical systems is applied to an analysis, modeling and processing the time series of emission intensities of chaotic transmitter/receiver systems (two unidirectionally coupled semiconductor laser systems in the all-optical scheme) suited for encoding at rates of GBit/s. the problem of a signal processing is directly connected with the corresponding cybersecurity in some optical chaos communictaion systems. The estimated values for the dynamic and topologic invariants such as the correlation and Kaplan-York dimensions, Lyapunov indicators, Kolmogorov entropy etc for investigated chaotic signal time series of two unidirectionally coupled semiconductor laser systems in the all-optical scheme.

Optical chaotic communication using correlation demodulation between two synchronized chaos lasers

This paper theoretically investigates the scheme of optical chaotic communication based on correlation demodulation between two synchronized semiconductor lasers. In the scheme, a semiconductor laser (SL) system, which is subject to phase conjugation and electro-optical phase modulation feedback, generates optical chaos with high-complexity, simultaneously, the time-delay (TD) signature can be well concealed. We use the digital signal “0” and “1” to control the chaotic signal’s switching between two arms of electro-optical (E-O) switch to indirectly achieve spreading spectrum. Concretely, for the “0” bit, at the cross arm the waveform of the optical chaotic signal is reversed by utilizing the cross gain modulation (XGM) effect of semiconductor optical amplifier (SOA); for the “1” bit, the chaotic signal is exchanged from the cross arm into the through arm. Based on the four-wave mixing (FWM) effect of optical parameter amplifier (OPA), the optical chaotic signal is converted to the same center wavelength as SOA’s output, and then two chaotic sequences are coupled into a channel in turn, as a results, the power of the signal of 5 Gbit/s is uniformly distributed and expanded to about 23.45 GHz bandwidth, thus its power spectrum density (PSD) becomes very low. We numerically demonstrate that this chaotic dynamics between the transmitter and the receiver can be identically synchronized due to coupling. The results indicate that the novel correlation-demodulation-based optical chaotic communication scheme can tolerate a higher noise level, and it can achieve a high-quality communication under lower signal-to-noise ratio (SNR). Compared with the scheme of synchronized error monitor, the correlation demodulation way has better ability for anti-noise interference.