This equivalent circuit can be obtained by appropriate handling of the rate equations and by transformations of variables. Finally, the Bpf source produces the optical output power of the laser in the form of a voltage. An increase in laser bandwidth is observed when I and g0 are simultaneously modulated.
Also in figure 13, the dependence of the critical modulation index (frequency bifurcation) is observed (for f = 12 GHz, mcritical is higher than for f = 7 GHz).
Particularities of modeling and simulation of quantum well solar cells
The simulation of refractive index and reflection of the solar cells with quantum sources was made with the Octave software, version 3.02. Simulation of the reflection dependence of λ, for a QW structure of a solar cell with an SiO anti-reflection coating. [30] summarizes the calculation results of the conversion efficiency for the cell parameters Nw=30,lw=20 nm and Ib=10 nm.
The dependence of the efficiency of MQW solar cell by the number of quantum wells.
Optical transmission system with laser chaotic carrier
Note that δ is the coupling factor of the transmitted field into the receiver's SPLD. When a small portion of the transmitted chaotic carrier is coupled into the receiver device, synchronization between the two lasers becomes possible (Figures 20 and 21), independent of the initial conditions of the two systems. To investigate the possibility of transmission information, we introduce the information as an amplitude modulation of the sinusoidal injection current in the transmitter laser.
The useful message can be recovered by low amount filtering½STð Þt SRð Þt =SRð Þt.
Conclusions
The structure of an automatic decision system for a large number of independent particle detectors.
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Infrared Sensors for Autonomous Vehicles
- Introduction
- Infrared spectrum
- Infrared radiation
- Sensitivity
- Spectral irradiance
- Light Detection And Ranging (LIDAR)
- Need for LIDAR in automotive
- Types
- Time of Flight LIDAR Operating Principle
- Emitter and detector options
- Eye safety
- Signal processing challenges
- Camera
- Exterior infrared camera (night vision)
- Exterior camera illumination challenges
- Interior camera – market need
- Interior camera illumination challenges
- Additional applications for interior camera
- Signal processing
- Exterior camera resolution requirement
- Sensor fusion
- Need for sensor fusion
- Challenges to sensor fusion
The object and event detection and response driver (OEDR) performs some or all of the dynamics. Performance from the driver of all DDT, even when enhanced by active safety systems. In addition, these wavelengths can reach the retina of the eye – so exposure must be controlled to avoid damage.
Target location is based on optics mapped onto the field of view and detector array. For example – the 3-dimensional road maps needed for autonomous driving are stored in the cloud (remote server) and real-time data is processed to only request changes and updates; thus reducing the amount of data typing that needs to be done in real time. However, at night the main source of visible light is usually car headlights.
To do this effectively, the human driver must be monitored as part of the environment in and around the car. One solution is to go to higher wavelengths (940 nm) – the challenge here is lower camera sensitivity. From a legal perspective, if the camera records the driver's face - the information can be pulled up in court if needed by a lawyer.
The next object I can think of is a solid stone placed on the road that, although small, can change the trajectory of the car. Improper or poor implementation of the sensor fusion can quickly return the car to the dealer showroom.
![Table 1. SAE J3016 – summary of levels of driving automation [3].](https://thumb-ap.123doks.com/thumbv2/1libvncom/9201396.0/30.918.103.812.250.799/table-sae-j-summary-levels-driving-automation.webp)
Author details
These questions will take longer to resolve as technology improves in sensors, computing, public acceptance and legislation. The 80/20 Pareto Principle would mean that the last 20% of the problems for self-driving cars will take 80% of the time it takes to bring it to the mass market. The exponential growth of electronics in the automotive industry can be gauged by the number of sensors and electronic control units (ECUs) being added to each new car.
Much technology still remains to be innovated and matured before regulations and standards are introduced. LIDAR technology is still evolving - the range, resolution, eye safety, form factor and cost of the technology are improving rapidly. The camera hardware for medium range and VGA resolution is mature - but needs improvement in range (200m targeting), resolution (> 8 megapixels) and low-light or infrared performance.
Real-time operation using artificial intelligence - Neural networks are still at an early stage.
Selection of our books indexed in the Web of Science™ Core Collection Book Citation Index (BKCI).
Optoelectronics Flexible Logic Gate Using a Chaotic Doped Fiber Laser
- Theoretical arrangement
- Implementation of the optoelectronics flexible logic gate using the EDFL
- Results and discussions
- Conclusions
Recently, some of the authors of this work proposed a flexible optoelectronic logic gate based on a fiber laser [27, 28]. Here, we describe in detail the implementation of the flexible optoelectronic logic gate based on the EDFL, which exploits the inherent richness and complexity of chaotic dynamics. This chapter is an extension of the article “Flexible optoelectronic logic gate based on a fiber laser.
The experimental setup of the optical logic gate based on EDFL is given in Section 3. Likewise, the discussion of theoretical and experimental results on the application of NAND and NOR logic gates based on EDFL as a function of the threshold controller is presented in Section 4. The energy level diagram of the theoretical model used in this work is shown in Figure 1.
To understand the dynamics of the EDFL, the bifurcation diagram of the local maximum of the laser power versus the pump modulation frequency was calculated. The current and temperature of the LD are controlled by a laser diode controller (LDC) (Thorlabs ITC510). The output of the logic gate V0 is sent to the driver (Pump) of the EDFL to change its dynamics.
To use the optoelectronic logic gate setup shown in Figure 5, it is necessary to determine Vc and Vin signals and find the required logic gates NAND or NOR. The numerical results of NOR and NAND operations of the reconfigurable dynamic logic gate Eq. Similar to the results of the numerical simulations, a change has been made to the parameters for Vc versus V to determine the required logic NAND or NOR gates. Figure 10 shows the values of Vc.
Experimental characterization of the bifurcation structure in an erbium-doped fiber laser with pump modulation.
Perovskite Solar Cells: The Challenging Issues for Stable Power Conversion Efficiency
Stable Power Conversion Efficiency
- Photovoltaic effect
- Desired properties for best solar absorber
- Replacement of lead in perovskite structure
- Modifications for better and possible photovoltaic materials
- Conclusion
In fact, the solar energy that hits our planet in 1 hour is equal to the total amount of energy used by all the people in the world in a year. In 2013, perovskite solar cell technology was declared one of the greatest scientific breakthroughs by the editors of Science and Nature [14]. Despite the advantages of perovskite processing, the poor stability of organic-inorganic hybrid combinations with respect to moisture, heat, light and oxygen must be overcome before the technology can be commercialized.
The potential difference developed across the cell when the terminals are not connected is known as open-circuit voltage Voc, which depends on the band gap of the absorber layer. Here we highlight some of the key features to be addressed during device manufacturing. How suitable the materials are for photovoltaic applications would be determined by how close the photon energy is to the bandgap of the material.
One of the promising strategies to realize the absorption enhancement is the synthesis of solar cell devices using the materials with the band gap as quantified by the well-known Shockley-Queisser limit [17]. One of the important properties is a reasonably high carrier mobility for the development of solar cell architecture, as it determines the range of properties available by forming mixed compounds in a compatible material. The stability problem was solved by introducing the changes in the composition by simply losing 5% of the original power conversion efficiency [27].
One of the obvious implementations was done to find a lead-free absorber in meso-structured perovskite solar cells such as CsGeI3 and CH3NH3GeI. Therefore, it is very interesting to focus on the optoelectronic properties of the lead-free materials to achieve the environmentally friendly and stable photovoltaic perovskite devices.
Acknowledgements
The bandgap along with effective mass tuning is possible by replacing the ions in the structure. It has previously been reported that slightly replacing the methylammonium content with formamidinium ions in lead-based perovskites can somehow narrow the bandgap and there are also some theoretical arguments suggesting that smaller cations could narrow the bandgap [44]. Therefore, the bandgap of strontium-based perovskite can be reduced if the organic cation were replaced by an inorganic cation or if the cation size change will directly affect the geometric changes, such as tolerance factor and octahedral tilt.
Although the substitution of organic cation can reduce the band gap, which is the most crucial part to achieve high efficiency of perovskites for solar cell applications. The approach of using Goldschmidt's rules together with additional quantum mechanical considerations may provide a promising route to replace lead, as well as general insight into metal halide-perovskite photovoltaic technology. Materials other than lead halide perovskites appear to be more stable and have some good features, but the overall energy conversion efficiency of these materials is low.
Consequently, it would be very beneficial from a toxicological, marketing and more importantly legal point of view if we could manage to replace the lead in perovskite solar cells without seriously impairing their overall performance. However, the combination of lead-free materials with robust optoelectronic properties with full stability under environmental conditions cannot be ruled out in the near future. Identification of defect-tolerant semiconductors with high minority carrier lifetimes: beyond hybrid lead halide perovskites.
Effect of metal cation substitution on the electronic structure of organometallic halide perovskites: Replacement of lead with alkaline earth metals. Goldschmidt rules and strontium substitution in lead halide perovskite solar cells: theory and preliminary experiments on CH3NH3SrI3.
