The difference between Passive Optical Network (PON) and Active Optical Network (AON)

 

 

Passive optical network (PON) and active optical network (AON) are two access technologies for building DWDM and CWDM backbone networks in FTTH systems. Both have their own advantages, so what are the main differences between them? How should we choose?

 

Signal Distribution

The difference in signal distribution is the biggest difference between passive optical network (PON) and active optical network (AON). In a passive optical network (PON), there is a situation where optical fiber bundles are shared between users, while in an active optical network (AON), each user has an independent optical fiber chain, and there is no shared bandwidth between each other , Therefore, relatively speaking, the passive optical network (PON) system does not run as fast as the active optical network (AON), and it is more difficult to troubleshoot when a fault occurs.

 

Cost

As we all know, the main sources of network costs are power supply equipment and maintenance costs. It can be seen from the above that the passive optical network (PON) has no other power supply equipment except for both ends, and requires less maintenance and no power supply; while the active optical network (AON) mainly uses power supply equipment for network transmission, so relatively In general, the cost of active optical network (AON) is higher than that of passive optical network.

 

Coverage

Passive optical networks (PONs) typically only cover distances up to 20 kilometers, while active optical networks (AONs) can cover distances up to about 100 kilometers. In other words, users in the passive optical network (PON) must be closer to the input signal.

 

Application Range

In addition to the factors mentioned above, practical applications also need to consider other factors. For example, when it comes to radio frequency deployment and video services, it is more appropriate to choose Passive Optical Network (PON); if the target users have higher requirements on the network or a large number of users (such as commercial customers or multiple residential buildings), choose Active Optical Network (AON) is more suitable.

 

In addition to the differences mentioned above, there are other differences between the two networks. For example, industry standards, popularity, etc.

What are the parameters of the optical module?

 

The parameters of optical module mainly include transmission rate, Center wavelength, Transmission distance, Single-mode/multi-mode, Interface type, etc.

 

Multimode has large loss but small dispersion during transmission, And is suitable for short-distance transmission, While single-mode has small loss but large dispersion during transmission, And is suitable for long-distance transmission.

 

Loss refers to the loss of optical energy caused by absorption, scattering and leakage of the medium when light is transmitted in the optical fiber. This part of the energy is dissipated at a certain rate with the increase of the transmission distance.

 

Dispersion occurs mainly because electromagnetic waves of different wavelengths travel at different speeds in the same medium. As a result, Different wavelength components of the optical signal reach  the receiving at different times due to the accumulation of transmission distances, Resulting in pulse broadening and inability to distinguish signal values.

 

Above all is the entire content of optical module parameters. For more information on optical module products, please follow the official website of Sanland Technology. Thank you for your support!

At present, an effective method to solve the increasing bandwidth of information transmission is to use CWDM equipment and DWDM equipment, but they are different in many aspects.

1. Channel spacing between CWDM equipment and DWDM equipment

 

Channel spacing is defined as the difference between the nominal carrier frequencies of two adjacent optical channels, and is generally used to prevent inter-channel interference. CWDM  has a wider spacing than DWDM, it can transmit 18 wavelengths in the spectral grid of 1271 nm to 1611 nm, and the channel spacing is 20 nm. DWDM can transmit 40, 80 or 160 wavelengths, and the channel spacing can be 0.8 nm.

2. Transmission distance between CWDM equipment and DWDM equipment

Since the wavelength of dense wavelength division multiplexing equipment (DWDM) is highly integrated during optical fiber transmission, DWDM equipment can transmit longer distances than CWDM equipment. CWDM equipment currently cannot achieve unlimited distance transmission, and its maximum transmission distance is only 160 kilometers, while the transmission distance of DWDM equipment far exceeds that of CWDM equipment.

3. Modulated lasers of CWDM equipment and DWDM equipment

The system of CWDM equipment has lower requirements on the technical indicators of the laser, and generally an uncooled laser can be used; the system of DWDM equipment needs to use a cooled laser, and the cooling laser adopts a temperature adjustment method to ensure the stability of the DWDM system. With better performance, higher safety and longer service life, DWDM consume more energy than CWDM equipment.

4. Cost of CWDM equipment and DWDM equipment

Because the temperature distribution of the DWDM equipment system is uneven in a wide wavelength range, when the cooling laser technology is used to adjust the temperature, the use cost of the DWDM equipment system is increased. In addition, the system of DWDM equipment is usually four to five times more expensive than the system of CWDM equipment. However, with the increasing popularity of DWDM, the price of DWDM optical modules is nearly 20%-25% lower than that of CWDM optical modules.

What is the Recrystallization Process?

 

Recrystallization is an important phenomenon in materials science that involves the microstructural recovery of material after plastic deformation. This process is crucial for understanding material properties and optimizing processing techniques.

 

Mechanisms and Classification of Recrystallization

 

Recrystallization processes are typically triggered by heat treatment or thermal deformation and involve the natural recovery of materials after the generation of defects during deformation. Defects such as dislocations and grain boundaries promote the reduction of system-free energy at high temperatures through dislocation rearrangement and annihilation, leading to the formation of new grain structures.

Recrystallization can be classified into static recrystallization (SRX) and dynamic recrystallization (DRX). SRX occurs during annealing processes, while DRX takes place during thermal deformation. Furthermore, recrystallization can be further subdivided based on specific mechanisms, such as continuous dynamic recrystallization (CDRX), discontinuous dynamic recrystallization (DDRX), geometric dynamic recrystallization (GDRX), and metadynamic recrystallization (MDRX). These classifications are not strictly defined, and researchers may have different interpretations.

 

Factors influencing recrystallization

 

The recrystallization process is influenced by various factors, including the stacking fault energy (γSFE), initial grain size, thermal processing conditions, and second-phase particles. The magnitude of the stacking fault energy determines the dislocation breakdown and mobility, thereby affecting the recrystallization rate. Smaller initial grain sizes and suitable thermal processing conditions, such as high temperature and low strain rates, facilitate recrystallization. Second-phase particles can significantly influence the recrystallization process by hindering grain boundary motion.

 

Application of imaging techniques

 

EBSD and TEM are two classic imaging techniques used in recrystallization studies. EBSD analyzes the distribution and percentage of recrystallized grains using the DefRex map, although resolution limitations may pose accuracy issues. TEM, on the other hand, provides a direct observation of material substructures, such as dislocations, offering a more intuitive perspective for recrystallization studies.

 

Application of EBSD in recrystallization studies

 

EBSD is used to determine whether grains have undergone recrystallization by observing grain boundaries. For example, in the DefRex maps of forged TNM alloys, grains surrounded by high-angle boundaries are typically considered recrystallized grains. This technique provides detailed information about grain orientations and grain boundary types, aiding in the understanding of microstructural changes during recrystallization.

 

BC+GB (grain boundary) map of forged TiAl alloy

 

Application of TEM in recrystallization studies

 

TEM allows for more in-depth observations. For instance, in TEM images of rolled TiAl alloys, defect-free equiaxed grains, which are recrystallized grains, are clearly visible. This technique reveals the submicron-scale structures of materials, including dislocation arrangements and grain boundary characteristics, which are essential for understanding recrystallization mechanisms and optimizing material properties

Lithium Iron Phosphate battery:

Lithium Iron Phosphate Battery is a rechargeable types of battery which features lithium ions that moves from the negative electrode to the positive electrode during discharge and comes back to its original points while charging.

Fig: Schematic of working mechanism of Lithium-iron phosphate battery

Advantages of Lithium Iron Phosphate (LiFePO4) battery:

Smaller and lighter: Lithium Iron Phosphate (LiFePO4) battery is lighter than other rechargeable batteries in consideration of battery capacity. This makes it more practical in portable consumer electronic devices in which physical specifications such as weight and form factor are considered important selling points. Generally lithium battery weight is 30% from the lead acid batteries.

High efficiency: Most lithium-ion batteries have more than 95% efficiency (in 1C discharge), meaning that 95 percent or more of the energy stored in a lithium-ion battery is actually able to be used in 1C discharge. Conversely, lead acid batteries see efficiencies closer to 50% in 1C discharge.

Fast charging ability: Lithium batteries have superior fast charging ability over Lead acid batteries. With appropriate battery charger, then can be 90-100% charged within 1-3hours where as general lead acid batteries take more than 10-12 hours to fully charge.

High energy density: This is one of the highlighted advantages of lithium iron phosphate battery technology. With the increased density of energy this battery technology is being used from smart phones to the high end electric vehicles. The theoretical energy density of lead acid is 35-50 Wh/kg where as lithium batteries have usually 120-260Wh/kg.

Depth of discharge: Lead-acid batteries should only be run to 50% depth of discharge. Beyond that point, you risk negatively affecting their lifespan. In contrast, lithium batteries can handle deep discharges of 80% or more. This essentially means they feature a higher usable capacity.

Self-discharge: Other rechargeable batteries are not good with the rate of self-discharge. Due to the existence of Lithium iron cells in the battery the self-discharge rate is quite lower than others. It is around 5% for the first four hours and drops to around 1-2% per month.

Low maintenance: It does not require constant maintenance to continue its flawless performance whereas Lead-acid is a tried-and-true technology that costs less, but requires regular maintenance and doesn’t last as long.

Availability of variety: There are several types of lithium ion cells which can be used accordingly as per the requirement for a particular application.

Zero to low memory effect: Lithium Iron Phosphate (LiFePO4) battery has zero to minimal memory effect. This memory effect is common in nickel-metal hydride rechargeable batteries such as NiCd and NiMH.

High open-circuit voltage: Lithium Iron Phosphate battery has a chemistry that results in higher open-circuit voltage than other aqueous    batteries such as lead acid, nickel-metal hydride, and nickel-cadmium.

The Lithium Iron Phosphate Battery have eventually become popular and its demand has drastically grown up to much greater extent  in  past few years. There are various lithium iron phosphate battery manufacturers who have been producing such batteries to fulfill the needs  as per the demand and fill the gap between the demand and supply. But we need to understand the advantages and the limitations of this technology for choosing the right backup battery for us.

In modern society, more and more attention is paid to saving energy and reducing carbon emissions. With the increasing demand for energy conservation and emission reduction in the global market, the market demand for high light efficiency chips is also growing.

 

What are high light efficiency chips?

High-efficiency chips ‌are those that produce more light output for the same amount of power and are commonly used in lighting and display devices. This kind of chip has the advantages of high luminous efficiency, energy saving, environmental protection, long life, etc., and is a high-performance component commonly used in modern electronic equipment.

 

What are the technical characteristics of high light efficiency chips?

1. High Luminous Efficiency: Can efficiently convert electric energy into light energy, reduce energy consumption.

2. Energy Saving and Environmental Protection: The use of high light efficiency chips can significantly reduce energy consumption and reduce carbon emissions.

3. Long Life: Compared with traditional light sources, high light efficiency chips have a longer life, reducing replacement frequency and maintenance costs.

4. Small size: High light efficiency LED lights are small in size and suitable for installation needs of various application scenarios.

 

High Light Efficiency LED Farming Light

In terms of lighting, high light efficiency LED lamps have better energy-saving effects and longer service life than traditional incandescent lamps and energy-saving lamps. For example, after the use of high light efficiency chips, our LED Poultry Farming Light products have been upgraded to High Light Efficiency LED Poultry Farming Light products. It can efficiently convert electric energy into light energy, reduce the loss of electric energy into heat energy, improve the overall energy efficiency, and thus reduce energy consumption. The bulbs have a long service life, can work tens of thousands of hours continuously, reduce the cost of replacement and maintenance. This is an outstanding example of Environmental Friendly LED Poultry Farming Light.

 

 

As cities around the world become more connected and technologically advanced, interactive flat panels (IFPs) are emerging as key players in shaping the future of smart cities. These cutting-edge displays go beyond traditional screens, offering interactivity, real-time information sharing, and collaboration. As urban spaces continue to evolve, IFPs are playing an increasingly vital role in creating more efficient, sustainable, and inclusive communities.

 

Here are five compelling reasons why interactive flat panels are set to revolutionize smart cities:

 

1. Revolutionizing Public Spaces with Digital Signage and Information Dissemination

In a smart city, public spaces are not just areas to pass through—they are hubs for communication and engagement. IFPs are transforming public spaces by providing dynamic digital signage that goes far beyond static advertisements. From interactive kiosks in malls to real-time bus schedules at transportation hubs, IFPs serve as the heart of a city’s digital communication system.

• Real-Time Information
• Interactive Engagement
• Localized Content

 

2. Smart Classrooms and Public Libraries: Bringing Education into the Digital Age

As education becomes more technology-driven, smart classrooms and public libraries are increasingly turning to interactive flat panels to enhance learning and collaboration. These digital tools provide more than just a display—they create an interactive learning environment that adapts to the needs of students and educators alike.

• Interactive Learning
• Enhanced Accessibility
• Collaboration and Inclusion

 

3. Enhancing Smart Transportation Systems with Real-Time Information

Transportation is a critical component of any smart city, and IFPs are playing a significant role in improving the way people navigate and experience urban transit systems. From bus stations to subway entrances, interactive flat panels are transforming transportation hubs into smarter, more efficient spaces.

• Real-Time Transit Updates
• Interactive Maps and Navigation
• Smart Ticketing

 

4. Promoting Public Engagement and Community Innovation

Public engagement is a key principle in building a successful smart city, and interactive flat panels are an effective tool for fostering communication between city authorities and citizens. IFPs can serve as a platform for public participation in decision-making processes, community-driven innovation, and civic engagement.

• Participatory Decision-Making
• Community Projects and Initiatives
• Collaborative Innovation

 

5. Integrating Interactive Flat Panels into Smart City Infrastructure

As smart cities continue to evolve, the integration of interactive flat panels into the broader city infrastructure is key to unlocking their full potential. IFPs can serve as a foundational element in connecting and streamlining urban systems.

• Centralized Control and Management
• Sustainability
• Seamless Integration with IoT

 

The integration of interactive flat panels into smart city frameworks is ushering in a new era of urban living, where communication is more dynamic, transportation is more efficient, and public engagement is more inclusive. By enabling real-time information sharing, collaboration, and interactivity, IFPs are playing a central role in transforming cities into smart, sustainable, and connected communities. As technology continues to evolve, interactive flat panels will undoubtedly be a driving force in shaping the cities of tomorrow.

In today’s rapidly evolving education landscape, technology plays an increasingly important role in fostering engaging and effective learning experiences. Interactive flat panels (IFPs) are at the forefront of this transformation, especially in early childhood education, where interactive and sensory learning are crucial for young learners.

 

1. Engaging Visual and Interactive Learning
Interactive flat panels bring vibrant visuals, touch-sensitive capabilities, and engaging content to the classroom, capturing young children's attention effortlessly. With high-resolution displays and multi-touch capabilities, children can interact with content directly on the screen, encouraging hands-on learning and exploration. Whether it’s learning numbers, letters, or shapes, the immersive experience makes learning fun and memorable.

 

2. Promoting Collaboration and Creativity
IFPs support collaborative activities, enabling multiple children to work together on interactive games, drawing activities, or group problem-solving tasks. With tools like virtual whiteboards and annotation features, children can express their creativity, share ideas, and learn teamwork from an early age.

 

3. Personalized and Adaptive Learning
Interactive flat panels are equipped with various educational apps and adaptive learning software that can adjust to the pace and preferences of individual learners. Teachers can use these tools to personalize lessons, catering to different learning styles and ensuring no child is left behind.

 

4. Simplifying Teaching for Educators
For teachers, IFPs simplify lesson planning and execution. With integrated software, cloud storage access, and real-time connectivity, educators can create dynamic lessons, access a wealth of online resources, and present multimedia content seamlessly. The ability to save and share lesson notes also ensures continuity and ease of review for both teachers and students.

 

5. Building Digital Literacy from an Early Age
Incorporating IFPs into early childhood education helps build digital literacy skills from a young age. By interacting with technology in a controlled and educational setting, children become comfortable using digital tools, laying the foundation for future learning and tech-savviness.

 

6. Encouraging Safe and Engaging Screen Time
With features like blue light filters and anti-glare screens, IFPs ensure that screen time is safe for young eyes. Moreover, the interactive nature of the devices promotes active engagement rather than passive consumption, making screen time a constructive part of the learning process.