The finite element method (FEM) is essentially very complex math used by engineers to reduce the number of prototypes and virtual experiments necessary to create a successful design. In previous posts, we discussed the advantages of the finite element method (FEM) and finite element analysis (FEA). Together, FEM and FEA are used to predict the structural behavior and integrity of a design.
Specialized finite element analysis software emerged in the 1970s. Now, it is common to find virtual testing integrated into the product development cycle. The global simulation software market size reached US$11.08 billion in 2020. It’s expected to grow 17.5% by 2028 while the specific FEA software market is anticipated to grow nearly 9% over the same period.
Key factors to support this expected market revenue growth across several industries include the increasing need to reduce manufacturing costs, as well as the need to investigate critical situations without actual risks. Simulation software for problem solving and decision making will be important at almost every stage of manufacturing, including product design, testing, and market launch, to mitigate potential challenges and boost financial returns. These are just a few of the ways that various industries utilize FEM and FEA.
Manufacturing Industry
The manufacturing industry is facing problems due to a significant increase in manufacturing costs, rapid demand fluctuations, and excessive equipment investment. Consequently, the industry is faced with the challenge of simultaneously achieving eco-friendly, high-quality, and low-cost products. To meet these demands, organizations are making an effort to improve the efficiency of the manufacturing process using FEM to predict various variables such as die alignment, material size deviation, and working temperature.
Energy Industry
Currently, rethinking energy transport is essential due to its broader applications for different energy systems. The study of heat and mass transportation has received remarkable consideration by physicists, engineers, and mathematicians. Researchers are looking at how to boost thermal transportation by mixing the nanoparticles in the base fluid mixture. Utilizing FEA, they are working to find numerical and graphical outcomes related to velocity and temperature versus various parameters. The present developments are applicable in automobile coolants, as well as the dynamics in fuel and the production of solar energy.
Rail Industry
In designing for passenger rail vehicle safety, one of the most challenging tasks for design engineers in the rail industry is predicting material durability. Numerical simulation is a convenient solution for prediction challenges, but a model’s predictions strongly depend on the availability—and accuracy—of material and assembly data. Advanced adhesive properties can provide designers with a robust data package to address modeling challenges through complex calculation methods or FEA. For multiple passenger rail interior and exterior applications, 3M has characterized three of its structural adhesive technologies to meet data requirements for two safety classes.
Commercial FEA Software
Ansys Mechanical recently became one of the first commercial finite element analysis (FEA) programs supporting AMD Instinct™ accelerators, which are the newest data center graphics processing units (GPUs). The accelerators are designed to provide exceptional performance for data centers and supercomputers to help solve the world’s most complex problems.
“Today’s large, complex engineering challenges require quick, predictively accurate simulations that scale,” said Brad McCredie, corporate vice president at AMD. The collaboration between Ansys and AMD will enable a notable speed boost for applications, which will allow researchers to run complex structural simulations in order to drive higher quality, more efficient designs for cars, planes, and a range of other products.
Discover the Finite Element Method (FEM)
Learn one of the most powerful numerical approaches available to engineers. Finite Element Method for Photonics, a five-course program, covers the fundamental principles of FEM while providing participants with insight into the method.
Connect with an IEEE Content Specialist today to learn how to get access to this program for your organization.
Interested in access for yourself? Visit the IEEE Learning Network (ILN)
Resources
3M. (17 August 2022). Designing for passenger rail vehicles safety and durability. Railway Gazette International.
Ansys. (24 August 2022). Ansys and AMD Collaborate to Speed Simulation of Large Structural Mechanical Models Up to 6x Faster. Cision PR Newswire.
Brush, Kate. (Accessed 30 August 2022). DEFINITION: finite element analysis (FEA). TechTarget.
Emergen Research. (10 August 2022). Global Simulation Software Market Is Expected to Grow Steadily At CAGR Of 17.5% In The Forecast Period Of 2021-2028. EIN Newswires.
Ho Seo, Young. (2 August 2022). Development of smart cold forging die life cycle management system based on real-time forging load monitoring. Scientific Reports.
Infinium Global Research. (July 2022). Finite Element Analysis [FEA] Software Market: Global Industry Analysis, Trends, Market Size, and Forecasts up to 2028. Research and Markets.
Sohail, M., Nazir, U., El-Zahar, E.R. et al. (5 August 2022). Galerkin finite element analysis for the augmentation in thermal transport of ternary-hybrid nanoparticles by engaging non-Fourier’s law. Scientific Reports.
The finite element analysis (FEA) is leading to major breakthroughs in nanotechnology, and having a huge impact on a number of industries spanning electronics, material science, quantum science, engineering, and biotechnology, AZO Nano reported.
Simulations based on FEA, a complex mathematical technique, is giving engineers valuable insight into the mysterious mechanical properties of polymer nanocomposites used as filler in polymer manufacturing and processing. These properties offer a revolutionary alternative to conventional polymer composites, including enhanced abrasion resistance, less shrinkage, and residual stress, as well as advanced thermal, electrical, and optical properties.
Nanomaterials are much smaller than traditional materials, and are therefore typically not as effective. As such, it is crucial for engineers to understand how the materials will react under stress in order to improve their design. While FEA is just one technique used to test these designs, its unique abilities provide significant insight into their properties.
What is FEA?
As we previously reported, FEA is based on the finite element method (FEM), a technique that can help solve highly complex math equations. A simple way to understand FEM is to look at it as separating a large problem into a series of smaller ones (“finite elements”), making the overall problem easier to see. FEA is the mathematical equations behind FEM that is applied to create a simulation. The simulation breaks down the entire model into smaller elements within a mesh, which engineers use to test how the different elements of a design interact and perform under simulated stressors.
There are many benefits of using FEA. For one, its insight into how the various elements of a design are interacting in minute detail provide enhanced accuracy of structural analysis. Furthermore, FEA allows engineers to create virtual simulations thereby reducing the need for physical prototypes and testing in order to save time and money.
How Are Engineers Using FEA for Advancing Nanotechnology?
Using FEA, researchers have discovered that high interfacial stress can cause the nanofiber or matrix in the material to come apart. They were able to control the properties which improve the strength of the interface to generate the best stress transfer. They discovered that the accumulation of stress concentrations at the interface between the fiber and the matrix can reveal the effective matrix-to-nanofiber stress transfer. Additionally, engineers can use FEA to simulate the composition of nanocomposites and nanotubes in the polymer, which would strengthen their mechanical properties by organizing thousands of nanotubes in a specific pattern.
What Industries Are Benefiting From This Research?
The aerospace sector is using FEA to model and test the effectiveness of polymer nanocomposites-based structures. FEA is also used by the manufacturing sector to simulate the necessary properties of polymer nanocomposites for use in packaging and coating applications.
Engineers are also using FEA to make breakthroughs in the field of photonics. Examples include using FEA to analyze four-wave mixing of topological edge plasmons in graphene metasurfaces; to demonstrate a feasible way to control light on integrated photonics and free-space metasurfaces; and to develop advancements in surface-emitting semiconductor lasers and optical lenses. Learn more about how photonics researchers are using FEA to advance their field.
Problem-Solving Applications with Photonic Devices
Providing a comprehensive and up-to-date account of FEM in photonics devices, with an emphasis on practical, problem-solving applications and real-world examples, Finite Element Method for Photonics is a five course-program from IEEE. Created by Dr. Agrawal, learners will gain an understanding of how mathematical concepts translate to computer code finite element-based methods after completing this program.
Connect with an IEEE Content Specialist today to learn how to get access in order to train your organization.
Interested in the course program for yourself? Visit the IEEE Learning Network (ILN).
Resources
Ahsan, Muhammad Adeel (27 April 2022). Finite Element Analysis of Polymer Nanocomposites. AZO Nano.
The Finite Element Method (FEM) is a popular tool used by engineers to reduce the number of prototypes and virtual experiments necessary to create a successful design. It uses complex mathematics to create virtual simulations that can realistically test the integrity of a design.
As discussed in a previous post, FEM is a numerical solution for a complex problem, which is used to create simulations. These simulations break down a large problem into a mesh of smaller elements that help researchers understand how all the minute details of a design are working together, which saves them time and money. In the past, FEM was predominantly used by engineers to test the potential of physical designs, but today it is used for much more.
What is the History of the Finite Element Method?
While FEM is a relatively modern invention, its roots go back to the 18th Century mathematician Leonhard Euler, who invented a method for solving ordinary differential equations with a given initial value. In the 1940s, engineer Alexander Hrennikoff and mathematician Richard Courant would build off of this method to perfect what is now considered FEM. As Trevor English in Interesting Engineering reports, the method was largely used in the 1950s to create designs for civil engineering and aerospace. Eventually, it would also be used to solve problems for computational fluid dynamics. It wasn’t until the 1990s, however, that the technology had enough computing ability to receive more widespread use. At that time, it began to expand to vehicle manufacturers, who used it to make more aerodynamic cars. Engineers that study computational fluid dynamics (CFD), a branch of fluid mechanics, also began to use it.
“For many modern engineers, understanding the complex mathematics behind CFD isn’t necessary to run simulations,” writes English. “The tools are not only being used by experts in fluid dynamics and mathematics, but they can also now be accessed by the everyday engineer having virtually any skill level.”
Photonics Researchers Embrace FEM
More recently, photonics engineers have begun embracing FEM to test their research and designs. Whereas FEM traditionally is used to test physical designs, it takes on a different role in photonics research, according to Dr. Arti Agrawal. Dr. Agrawal is a professor at the School of Electrical and Data Engineering at the City University of London, an IEEE Photonics Society Member, and author of the book, “Finite Element Modeling Methods for Photonics.”
“We want to know how the electric field and the magnetic field will change if the refractive index changes, what about the continuity of the field?” she said.
Some photonics researchers are already using FEM to make important discoveries, including research that sheds light on a new way to create low-threshold, surface-emitting laser diodes that span between the ultraviolet to deep visible range.
“Our studies open a new paradigm for developing low-threshold surface-emitting laser diodes from the ultraviolet to the deep visible (~200 to 600 nm), wherein the device performance is no longer limited by the lack of high-quality [distributed Bragg reflectors] DBRs, large lattice mismatch, and substrate availability,” the authors wrote in Science Advances.
FEM may be a new solution in the world of optics. However, it is already demonstrating a lot of promise.
Finite Element Method (FEM) for Photonics
Learn how FEM can be used to model and simulate photonic components/devices and analyze how they will behave in response to various outside influences. The Finite Element Method for Photonics course program, created by Dr. Agrawal, provides a comprehensive and up-to-date account of FEM in photonics devices, with an emphasis on practical, problem-solving applications and real-world examples. Engineers will gain an understanding of how mathematical concepts translate to computer code finite element-based methods after completing this program.
Connect with an IEEE Content Specialist today to learn how to get access to this program for your organization.
Interested in the course for yourself? Visit the IEEE Learning Network (ILN).
Resources
English, Trevor. (7 November 2021). What Is Finite Element Analysis and How Does It Work? Interesting Engineering.
Ra. Yong-Ho. Tonny Rashid, Roksana, Liu, Xianhe, Sadaf, Sharif, Mashooq, Kishwar, and Mi, Zetian. (3 January 2020). An electrically pumped surface-emitting semiconductor green laser. Science Advances.
Photonics engineers rely on optical simulations for their designs. Depending on the optical size of their model geometry, they need to choose the best method for performing these simulations, according to Christopher Boucher, a lead developer at COMSOL, a simulation software.
“The concept of optical size is essential to choosing a formulation for numerical simulation of electromagnetic waves,” Boucher writes in Laser Focus World. “Engineers working with simulation are constantly tasked with balancing accuracy against computational cost; we try to produce a model that best represents real-world behavior, but it must be within the time constraints of our assignment and with the limited computational resources at hand.”
If your simulation domain is only a few wavelengths across, Boucher recommends the finite element method as ideal. However, if it encompasses “a large number of wavelengths,” he says you will want to use the ray tracing method.
How should you use these methods to perform optical simulations? Here is what Boucher recommends:
Finite Element Method (FEM)
Using FEM, the model geometry is broken down into small mesh elements, in which equations are solved numerically. One way to model electromagnetic waves is through the “full-wave” method. It directly solves Maxwell’s equations for the electric field and accurately represents real-world phenomena without making too many simplifying assumptions.
“It can faithfully reproduce wavelength-scale behaviors such as diffraction and interference, which significantly impact the operation of nanophotonic devices,” writes Boucher.
However, he notes one problem with this approach. “The mesh must be fine enough to resolve individual oscillations of the electric field, so the simulations require more time and RAM to solve as the geometry size is increased. Therefore, this method is best suited for a model geometry that does not exceed a few wavelengths in all directions.”
Ray Tracing
Rather than solving individual waves on a very fine mesh, the ray tracing method represents “light as rays that can reflect and refract at boundaries between different media,” according to Boucher. However, he notes that this approach usually neglects wavelength-scale phenomena such as diffraction.
Other solutions
While FEM and ray tracing are adequate methods for many optical simulations, other methods may work better for complex problems. For example, if the geometry has one dimension that is comparable to the wavelength, but another dimension that is much longer, the beam envelope method may be preferable. According to Boucher, this method is “best suited for systems in which waves are constrained to propagate in one or two known directions, including in cables and directional couplers.”
Beginning with the full-wave solution, “in which the instantaneous electric field amplitude is resolved over each wavelength,” you can apply “a clever change of variables and instead solve for the amplitude of a slowly varying amplitude function,” which “relaxes the requirement from full-wave FEM that the mesh elements must be small enough to resolve individual wavelengths,” he explains.
Performing optical simulations can be a complex process. However, determining the best method based on your model’s geometry can simplify the process and lead to more successful outcomes.
Learn the Finite Element Method (FEM)
The new course program from IEEE Educational Activities provides a comprehensive and up-to-date account of FEM in photonics devices. Finite Element Method for Photonics has an emphasis on practical, problem-solving applications and real-world examples. Engineers will come away with an understanding of how mathematical concepts translate to computer code finite element-based methods.
Connect with an IEEE Content Specialist today to learn how to get access to this program for your organization.
Interested in the course for yourself? Visit the IEEE Learning Network (ILN).
Resources
Boucher, Christopher. (16 August 2021). Multiscale optical simulations pose unique challenges. Laser Focus World.
Researchers from Tokyo University of Science have developed a new design method that could lead to lighter, faster, and cleaner vehicles and airplanes. Their technique, published in Composite Structures, simultaneously optimizes fiber thickness and orientation. As a result, it reduces the weight of reinforced plastic parts commonly used in aerospace, civil engineering, and sports equipment.
Traditionally, efforts have mostly focused on enhancing the strength of carbon fiber composites. However, the Tokyo researchers’ new design method optimizes both fiber thickness and orientation. Typically, carbon fibers are combined with other materials to make a composite, such as carbon fiber reinforced plastic (CFRP), which is popular for its strength, rigidity, and high strength-to-weight ratio. Some studies have examined how to improve CFRPs, particularly through a technique called “fiber-steered design,” which optimizes fiber orientation to enhance strength. The fiber-steered design approach, however, had a major flaw.
“Fiber-steered design only optimizes orientation and keeps the thickness of the fibers fixed, preventing full utilization of the mechanical properties of CFRP,” research team member Dr. Ryosuke Matsuzaki told Canadian Plastics. “A weight reduction approach, which allows optimization of fiber thickness as well, has been rarely considered.”
“Simultaneous Optimization Technique” Reduces CFRP Weight Without Affecting Strength
Faced with this dilemma, the researchers proposed a new design technique for simultaneously optimizing orientation and thickness depending on the composite structure’s location, which reduced the CFRP’s weight without affecting strength. According to their research, the method includes three phases.
- The Preparatory Phase:
During this phase, the researchers performed an analysis using the finite element method (FEM). As we discussed in a previous post, FEM is a numerical solution that breaks down a much larger, complex problem into a series of smaller ones (“finite elements”) in order to make the overall problem easier to examine. This equation is then used to create a digital simulation known as the finite element analysis, which gives engineers a more detailed look into the design and how its various elements work together. The team used the simulation “to determine the number of layers, enabling a qualitative weight evaluation by a linear lamination model and a fiber-steered design with a thickness variation model.” - The Iterative Phase:
The team implemented the iterative process to “to determine the fiber orientation by the principal stress direction and iteratively calculate the thickness using ‘maximum stress theory.’” - The Modification Phase:
During this step, the researchers made “modifications accounting for manufacturability by first creating a reference ‘base fiber bundle’ in a region requiring strength improvement and then determining the final orientation and thickness by arranging the fiber bundles such that they spread on both sides of the reference bundle.”
This simultaneous optimization technique led to a weight reduction of more than five percent and allowed for higher load transfer efficiency than what fiber orientation achieves by itself. In the future, the method could reduce the weight of CFRP parts that support greener transportation systems.
“Our design method goes beyond the conventional wisdom of composite design, making for lighter aircraft and automobiles, which can contribute to energy conservation and reduction of CO2 emissions,” Dr. Matsuzaki told Canadian Plastics.
FEM analysis is becoming an increasingly popular research tool, including in the field of photonics, where the method has contributed to a number of recent breakthroughs. Check out some of the latest innovations in optics research supported by this simulation tool.
Finite Element Method (FEM) for Photonics
Learn how FEM can be used to model and simulate photonic components/devices and analyze how they will behave in response to various outside influences. The Finite Element Method for Photonics course program provides a comprehensive and up-to-date account of FEM in photonics devices, with an emphasis on practical, problem-solving applications and real-world examples. Engineers will gain an understanding of how mathematical concepts translate to computer code finite element-based methods after completing this program.
Connect with an IEEE Content Specialist today to learn how to get access to this program for your organization.
Interested in the course for yourself? Visit the IEEE Learning Network (ILN).
Resources
Tokyo University of Science. (24 May 2021). New optimization approach helps design lighter carbon fiber composite materials. ScienceDaily.
Tokyo University of Science. (2 June 2021). Tokyo researchers hit on new design method to reduce weight in reinforced plastics. Canadian Plastics.
Engineers are increasingly embracing computer simulations to test the structural integrity of their prototypes. These computer simulations are based on the finite element method (FEM) and finite element analysis (FEA), which work in unison to give engineers insight into the structural behavior of particular designs, so they can locate weak points and improve them.
While FEM and FEA can help test your engineering designs, there are a number of equations, principles, issues, and types of simulations you can consider before getting started.
What is the Finite Element Method?
FEM offers a numerical solution for a complex problem, which allows for some level of error. It is usually used when a math equation is too complex to be solved in a typical fashion. FEM breaks a large problem into a series of smaller ones known as “finite elements,” which make an overall problem much easier to analyze.
What is the Finite Element Analysis?
These complex math problems are used to create a computer simulation, or FEA, which provides a visual analysis of how a particular product or design would react under stress in the real world. It does this by breaking down the entire model into a mesh where engineers test how the different elements of a design would interact and perform under simulated stressors.
What are Differential Equations?
Differential equations describe both natural phenomena and physical phenomena found in engineering mechanics. Known as “partial differential equations,” (PDEs), these complex equations must be resolved in order to get an accurate prediction of how the prototype will behave and react under certain conditions, such as stresses and strains.
What are the Different Types of Partial Differential Equations?
There are different types of PDEs, which are important to understand before moving ahead with the FEA. These include:
Elliptic
Solving elliptic PDEs involves two primary methods, including Finite Difference Analysis (FDA), an approximate technique for solving partial differential equations, and Variational, in which small energy differences can lead to drastically different outcomes. For example, if a ceramic vase falls over while on the floor, it is unlikely to break. However, if it falls from a table, it’s very likely to break since it delivers more energy to the floor.
Hyperbolic
These PDEs uphold solutions with discontinuities commonly associated with “jumps.” Wave equations are an example. These explain the movement of strings, wires, and fluid surfaces, such as waves in a body of water.
Parabolic
These PDEs depict time-dependent diffusion problems. Examples include particle diffusion and heat conduction.
Mesh Convergence
An important but often ignored issue in computational mechanics, mesh convergence can impact the accuracy of a FEA simulation. Mesh convergence is associated with how small elements have to be to guarantee the solutions of an analysis are not impacted by altering the size of the mesh. There are three main ways to measure mesh convergence: displacement error, strain error, and stress error. However, a few different errors can be defined to each of these, which can be compared and must reduce mesh refinement.
What are the Different Types of FEA?
Some of the major types of FEA include:
- Extended Finite Element Method (XFEM), which requires continuous displacements throughout elements.
- Generalized Finite Element Method (GFEM), which merges the features of classical FEM software with non-traditional meshless approaches.
- Mixed Finite Element Method, which is a merging of the use of automatic mesh refinement (h-refinement) with an increase in the arrangement of polynomials (p-refinement).
- Discontinuous Galerkin Finite Element Method (DG-FEM), which compared to traditional methods, many experts consider it to be a good alternative for solving hyperbolic equations.
Finite Element Method (FEM) for Photonics
Learn how FEM can be used to model and simulate photonic components/devices and analyze how they will behave in response to various outside influences. The Finite Element Method for Photonics course program provides a comprehensive and up-to-date account of FEM in photonics devices, with an emphasis on practical, problem-solving applications and real-world examples. Engineers will gain an understanding of how mathematical concepts translate to computer code finite element-based methods after completing this program.
Connect with an IEEE Content Specialist today to learn how to get access to this program for your organization.
Interested in the course for yourself? Visit the IEEE Learning Network (ILN).
Resources
What Is FEA | Finite Element Analysis? SIMSCALE.
(26 February 2021). Parabolic partial differential equation. Wikipedia
Rapp, E. Bastian (2017). Differential Equations. ScienceDirect.
MIT engineers recently designed a tunable “metalens” that can zero in on objects at multiple depths. The lens, constructed from a transparent “phase-changing” material capable of rearranging its atomic structure after heating, is capable of transforming how its material interacts with light.
The invention is a breakthrough in the field of photonics. Traditionally, changing the focus of a microscope or telescope to see at multiple scales meant having to physically move the lens, which required extra mechanical parts. However, metalens don’t need to be moved to change focus.
The engineers carved carefully patterned structures into the material’s surface, which form a “metasurface” that refracts light in different ways.
When the material’s property shifts, the optical function of the metasurface changes. For example, at room temperature, the metasurface focuses light to produce a crisp image of an object at a specific distance. When heat is applied, the material transforms its atomic structure. The metasurface then shifts light to focus on an object that’s further away. In other words, the metalens can change focus without the need for extra mechanical parts in the device.
This innovative lens could allow for the development of more flexible optical devices. A few potential use cases include a mini heat scope for drones, super-compact thermal cell phone cameras, and low-profile goggles for night vision.
“Our result shows that our ultrathin tunable lens, without moving parts, can achieve aberration-free imaging of overlapping objects positioned at different depths, rivaling traditional, bulky optical systems,” Tian Gu, a research scientist in MIT’s Materials Research Laboratory, told MIT News.
Photonics Researchers Use Finite Element Method to Test Devices with Metasurfaces
Increasingly, metasurfaces are becoming popular materials for use in optical applications. Due to their small size and unique properties, however, metasurfaces can be challenging to design.
“Metasurfaces are currently fabricated by highly demanding procedures that typically involve deposition of a transparent dielectric, followed by lithographic patterning, additional depositions, etching, and so on,” wrote researchers from Chalmers University of Technology in Sweden in a paper published in ACS Photonics. Their study focuses on new methods for creating phase-gradient metasurfaces that can improve the processing of metasurfaces.
Last year, photonics researchers used the Finite Element Method (FEM) to test a number of devices equipped with metasurfaces. As discussed in a previous post, FEM is a numerical solution that breaks down a much larger, complex problem into a series of smaller ones (“finite elements”) in order to make the overall problem easier to examine. This equation is then used to create a digital simulation (known as the finite element analysis), which gives engineers a more detailed look into the design and how its various elements work together.
With researchers discovering more and more breakthroughs in the field of photonics, FEM is quickly becoming a useful tool for aiding their designs.
Finite Element Method (FEM) for Photonics
Learn how FEM can be used to model and simulate photonic components/devices and analyze how they will behave in response to various outside influences. The Finite Element Method for Photonics course program provides a comprehensive and up-to-date account of FEM in photonics devices, with an emphasis on practical, problem-solving applications and real-world examples. Engineers will gain an understanding of how mathematical concepts translate to computer code finite element-based methods after completing this program.
Connect with an IEEE Content Specialist today to learn how to get access to this program for your organization.
Interested in the course for yourself? Visit the IEEE Learning Network (ILN).
Resources
(24 February 2021). Phase-changing metalens focuses without moving. Optics.org.
Chu, Jennifer. (22 February 2021). New “metalens” shifts focus without tilting or moving. MIT Materials Research Laboratory.
(16 June 2020). Metasurfaces allow ultra-thin camera lenses. Optics.org.
Andren, Daniel , Käll, Mikael, Martínez-Llinàs, Jade, Tassin, Philippe, Verre, Ruggero. (2020). Large-Scale Metasurfaces Made by an Exposed Resist. ACS Photonics.
The majority of medical, scientific, and industrial applications utilize high-power diode-lasers (HPDLs). Due to the common use of HPDLs, it’s more important than ever to prevent optical and physical malfunctions in high-power laser packages. However, as laser technology has become more advanced, HPDL output power has gotten larger, and with it, the waste-heat energy density of a sole diode laser bar has expanded from 200 W/cm2 to more than 600 W/cm2.
Thermal issues often result in failures when heat gets trapped in HPDL packaging. This impacts a number of outcomes, including output power, threshold current, slope efficiency, spectral broadening, wavelength shifts, and device lifetime. However, by designing high-power laser packages using finite-element method (FEM) simulations, potential for failures can be minimized.
As discussed in a previous post, FEM is a numerical solution that breaks down a much larger, complex problem into a series of smaller ones (“finite elements”) in order to make the overall problem easier to examine. This equation is then used to create a digital simulation (known as the finite element analysis), which gives engineers a more detailed look into the design and how its various elements work together.
Using FEM to Evaluate the Thermal Performance of High-Power Diode-Lasers
Thermal stress is a major challenge when it comes to HPDLs packaging. For instance, thermal stress often leads to mechanical tension in the diode and transforms the band structure, and this changes the characteristics of the diode laser in regards to threshold, wavelength, polarization, and SMILE ( near-field nonlinearity along the laser bar). Additionally, induced thermal stress in the laser device might harm the laser chips/bars and therefore reduce the device’s lifetime.
Recently, Chinese researchers from the Design and Simulation Technology Department at Focuslight Technologies used digital simulations, including FEM, to get an up-close look at how these kinds of potential failures can be avoided.
“The finite-element model (FEM) simulation results show that the compression stress on the laser bar decreases with the increase of copper-tungsten (CuW) submount thickness, as the CuW submount works as a buffer layer and can thus absorb stress,” the researchers wrote in Laser Focus World. “However, the laser bar out-of-plane strain (SMILE value) is approximately zero when the diode-laser array is directly bonded onto the heat sink without a submount; the SMILE value is maximized when the thickness of the CuW submount is increased to 44% of the heat sink. Beyond this point, the SMILE value decreases with increasing CuW submount thickness.”
Additionally, the authors used FEM to determine that adhesion in a corner of a microlens array diffuser was the source of cracking. After they controlled the adhesion in the FEM simulation, they found they reduced stress on the diffuser.
“Easy-to-use FEM methods have been presented for evaluating the thermal performance of HPDLs and the stress distribution in HPDLs. These methods make it much easier to understand the physics of the addressed thermal phenomena and predict their thermal behavior and performance,” they wrote.
Photonics Researchers Are Increasingly Relying on FEM
More and more, photonics researchers are using FEM. In a previous post, we discussed how engineers used FEM to demonstrate the potential for light-based circuits. In another post, we discuss how researchers demonstrated off-chip beam deflection and focusing with guided wave driven metasurfaces on silicon waveguides, which has the potential to transform traditional optics technology. These are just some of the ways researchers are using FEM to revolutionize photonics.
Learn how FEM can be used to model and simulate photonic components/devices and analyze how they will behave in response to various outside influences. The Finite Element Method for Photonics course program provides a comprehensive and up-to-date account of FEM in photonics devices, with an emphasis on practical, problem-solving applications and real-world examples. Engineers will gain an understanding of how mathematical concepts translate to computer code finite element-based methods after completing this program.
Connect with an IEEE Content Specialist today to learn how to get access to this program for your organization.
Interested in the course for yourself? Visit the IEEE Learning Network (ILN).
Resources
Wang, Jingwei, Fu, Tuanwei, and Liang, Xuejie. (11 November 2020). Simulation and modeling play key roles in high-power diode-laser packaging. Laser Focus World.
Optical lenses are vital components to the manufacturing and labeling of goods. For example, optical lenses are found in electronic devices like smartphones and laptops. They’re also used to make logos and graphics on hardware as well as other kinds of markings commonly found on commercial products and food packaging. These markings are created by high-powered lasers that pass through a series of optical lenses.
Computer simulation technology is important to the development of optical lenses, because it can reduce the number of prototypes needed during the design phase. These simulations give developers valuable insight into how to improve optical lens designs while also saving time.
There are a few simulation methods that can be used to analyze lens designs, from traditional techniques to those that solve all of Maxwell’s equations—a sophisticated set of equations that describe how electric charges and electric currents produce electric and magnetic fields.
Optical lens simulation relies on two categories. The first is design, in which a lens is optimized specifically for a certain function. The second is analysis, which gives a designer insight into what’s happening within the lens.
“Wave Optics” for Design
An example of optical lens design is the process of determining the ideal shape for a lens to direct a laser in a particular way. Typically, the goal of lens design is to reduce abnormalities as much as possible.
Simulations that employ ray-tracing, a process in which rays approximate electromagnetic waves, are often used for design. However, ray-tracing simulations don’t provide the effects of diffraction, which is characterized by light slightly bending as it passes over the edge of an object, so they aren’t 100% effective. In situations where it’s necessary to capture diffraction, “wave-optics” methods are considered ideal. These are computational high-frequency electromagnetics software that rely on a number of general-purpose numerical methods, including the finite-element methods (FEM). As discussed in a previous post, FEM is a numerical solution that breaks down a much larger, complex problem into a series of smaller ones (“finite elements”) in order to make the overall problem easier to examine. This equation is then used to create a simulation (known as the finite element analysis), which gives engineers a more detailed look into the design and how its various elements work together.
Unlike other methods, wave optics can be used for both design and analysis of optical lenses.
“Wave Optics” for Analysis
For optical lens analysis, Maxwell’s equations are necessary to acquire the electromagnetic fields’ complete vector representation. A simulation method known as “full-wave” uses FEM to solve the entire domain of Maxwell’s equations by breaking it down into a mesh. It is then subdivided into smaller elements with a simpler shape.
The full-wave method poses some challenges. For example, the innumerable mesh elements created can be difficult for a typical computer to handle. However, there are formulations to get around this issue.
Full-wave simulations for multicomponent optical systems were once thought impossible, but thanks to these FEM-based methods, the ability to simulate whole optical systems is closer than ever before.
Finite Element Method (FEM) for Photonics
Learn how FEM can be used to model and simulate photonic components/devices and analyze how they will behave in response to various outside influences. The Finite Element Method for Photonics course program provides a comprehensive and up-to-date account of FEM in photonics devices, with an emphasis on practical, problem-solving applications and real-world examples. Engineers will gain an understanding of how mathematical concepts translate to computer code finite element-based methods after completing this program.
Connect with an IEEE Content Specialist today to learn how to get access to this program for your organization.
Interested in the course for yourself? Visit the IEEE Learning Network (ILN).
Resources
Mizuyama, Yosuke. (15 September 2020). Full-wave simulation extends the range and depth of lens analysis. Laser Focus World.
Sjodin, Bjorn. (9 November 2017). Wave Optics: Beam-envelope method efficiently analyzes photonic components. Laser Focus World.
Exciting developments are happening in the fields optics and photonics. Some of these innovations are being made with the help of the finite element method (FEM). As discussed in a previous post, FEM is a numerical solution for a complex problem, which is used to create simulations. These simulations help researchers understand how all the minute elements of a design are working together, which saves them time and money. In the past, FEM was predominantly used by engineers to test the potential of physical designs.
“But in photonics, that’s not what we’re concerned about,” says Dr. Arti Agrawal, who is a professor at the School of Electrical and Data Engineering at the City University of London, an IEEE Photonics Society Member, and author of the book, Finite Element Modeling Methods for Photonics. “We want to know how the electric field and the magnetic field will change if the refractive index changes, what about the continuity of the field?”
Photonics Engineers Demonstrate The Potential for Light-Based Circuits
Light-based photonics integrated circuits are thought to have the potential to transform circuits. Unlike electricity-based chips, those that use light offer faster speeds, greater bandwidth, and more energy efficiency. There’s just one problem: Currently, they’re too big.
For light-based chips, also known as photonics integrated circuits, to become effective, they need to be much smaller. They will depend on compact integration of super-fast electro-optic functional elements on a single chip that doesn’t consume too much energy.
Recently, an electrical engineering team from the University of Rochester used FEM when testing a potential solution to this problem, which they published in the August edition of Nature Communications. Using thin-film lithium niobate (LN), the team made the tiniest electro-optical modulator ever created, which they say can serve as a platform for light-based photonics integrated circuits. To do this, they bonded the lithium niobate on a silicon dioxide layer. Not only does it represent the smallest lithium niobate modulator to date, it also works at high speeds and is efficient.
“The modulators enable efficient electro-optic driving of high-Q photonic cavity modes in both adiabatic and non-adiabatic regimes, and allow us to achieve electro-optic switching at 11 Gb s−1 with a bit-switching energy as low as 22 fJ,” reported the researchers in their study. “The demonstration of energy efficient and high-speed electro-optic modulation at the wavelength scale paves a crucial foundation for realizing large-scale LN photonic integrated circuits that are of immense importance for broad applications in data communication, microwave photonics, and quantum photonics.”
Professor Qiang Lin, one of the study authors, told the University of Rochester News that lithium niobate is a “workhorse material system for photonics research and development.”
“However current LN photonic devices, made upon either bulk crystal or thin-film platform require large dimensions and are difficult to scale down in size, which limits the modulation efficiency, energy consumption, and the degree of circuit integration. A major challenge lies in making high-quality nanoscopic photonic structures with high precision,” he said.
How Else Are Photonics Researchers Using FEM?
Increasingly, researchers are using FEM to test their research. In a previous post, we discussed how researchers demonstrated off-chip beam deflection and focusing with guided wave driven metasurfaces on silicon waveguides, which has the potential to transform traditional optics technology. Like the University of Rochester team, the researchers used FEM as part of their study, showing the potential this methodology has in impacting the future of photonics.
Finite Element Method (FEM) for Photonics
This course program from IEEE Educational Activities, Finite Element Method for Photonics, provides a comprehensive and up-to-date account of FEM in photonics devices, with an emphasis on practical, problem-solving applications and real-world examples. Engineers will come away from this program with an understanding of how mathematical concepts translate to computer code finite element-based methods.
Contact an IEEE Content Specialist today to learn more about getting access to these courses for your organization.
Interested in the course for yourself? Visit the IEEE Learning Network.
Resources
Marcotte, Bob. (26 August 2020). Photonics researchers report breakthrough in miniaturizing light-based chips. University of Rochester Newscenter.
Li, Mingxiao, Ling, Jingwei, He, Yang, Javid, Usman A., Xue, Shixin & Lin, Qiang.
(17 August 2020). Lithium niobite photopic-crystal electro-optic modulator. Nature Communications.
City, University of London. 7 August 2013. City, University of London: Dr Arti Agrawal – “Finite Element Modelling for Photonics.” https://www.youtube.com/watch?v=3GNG8eKioFA