Month: September 2022

What Should You Know When Designing Optical Passive Components For Aerospace Systems?

In aerospace systems, optical passive components play an important role. Primarily, they are used to carry out the telescope’s mission. Also, they help in establishing as well as extending communications in space missions. 

The use of optical passive components in aerospace systems is very wide. It’s very difficult to list them all together. Something or the other gets missed out. The surprising part is that all the names in the list of optical passive components are useful in aerospace systems. 

As optical passive components are crucial in aerospace systems, you should be very particular about their design and development. You cannot assume things and expect the components to deliver good results. It’s better to customize the components as per your requirements. And for this, you should work with an experienced and reputable optical passive components designer. 

You should perform thermal analysis 

Constant cycling of temperature in space is one of the biggest challenges for aerospace systems. The temperature ranges from extremely cold to severely hot within hours. To overcome this problem, you should perform a thermal analysis. 

With this analysis and testing, you will ensure that your components, boards, and devices can withstand the temperature swings. Deployment of the components will be easy in the changing temperature. a

You should do this analysis in addition to electro-thermal stimulation of the PCB layouts before fabrication. Other than this, you should consider thermal dissipation and distribution during manufacturing. 

You should apply parameter-based materials selection 

The materials for optical passive component designing should be selected based on different parameters. The parameters are defined to ensure the long-term usage of the components in aerospace systems. 

The two important parameters are mechanical and thermal. These parameters show the capability of the components to withstand the pressure and temperature challenges of space deployment. 

You should ensure good soldering and PTH fill quality 

Another potential problem of optical passive components in aerospace systems is outgassing, meaning condensation on lenses and absorption or diffraction prevention. This is caused by the release of trapped gas. 

The release of trapped gas can be stopped with good solder connections and vias. So, you should make sure that your optical passive components designer applies good quality control to the assembly process. 

You should keep the boards clean and properly packed

You cannot forget contamination issues associated with optical components used in aerospace systems. Even small amounts of debris or contamination disrupt or cease the operation of the systems. The ability of light to cross material boundaries gets disrupted. 

You can prevent contamination and any disruption to operation by cleaning, coating, and following good package and storage guidelines. The components should be assembled in certified clean rooms and sealing should be done strongly. If the boards have been in storage for long periods before deployment, you should bake them. 

Optical passive components provide several advantages to aerospace systems over other electronic options. This is just the beginning. In the future, utilization of the components is going to increase. So, you should follow the designing tips discussed in this post for better performance of aerospace systems with the help of the best optical passive components designer. 

Important Things You Should Know About Laser Cutting 

Laser (Light Amplification by Stimulated Emission of Radiation) cutting is a process in which the light spot is intensely focused onto an object because of the spatial coherence of laser light. This causes an extreme elevation in the temperature of illuminated areas, causing the object to melt rapidly or be vaporized. And thus, a cut or fissure forms in the object. 

Years ago, laser cutting was not so prevalent. Other cutting techniques were preferred, including manual cutting. And this is because people were not aware of it. Today, different reports estimate that the market for laser cutting will reach an expected level by 2024. One major reason for the growth of the market size of laser cutting is its processing on a wide variety of materials, such as a medium range of carbon steels, wood, plastic, and ceramics. 

The increasing need for laser cutting has introduced various technologies in the industry. So, engineers today have a wide choice of laser, machining principles, and computerized control. This helps them to precisely cut material with high-level accuracy, which wasn’t possible a few years ago. 

What are the laser cutting processes and types?

The laser cutting processes are:

Fusion cutting– It uses reaction inhibiting nitrogen or argon as the cutting gas. The advantage of fusion cutting is that it produces a virtually oxide-free cutting edge. 

Oxidative cutting– It uses oxygen as an assist gas, increasing heat and reaction rate at the cutting interface. This enables the cutting of thicker material at faster rates but with a less quality surface finish. 

Laser scribing– It is primarily used in the electronics industries to process thin films of material. 

In these three laser cutting processes, different types of lasers are used such as fiber or solid-state lasers and gas lasers, mainly a CO2 emission gas laser. 

Two different types of lasers 

CO2 gas emission laser– As one of the highest power continuous wave lasers available for cutting today, CO2 gas emission has been in service for the longest time. Also, it’s a mature technology.

For the functioning of CO2 laser parts, mirrors are needed that reflect the light into a monochromatic stream of light photons of high intensity that exit the laser at the wavelength. Here, water is used to cool the gas tube during stimulated emission and various gasses.

The benefits of CO2 laser cutting are that it cuts thicker materials at equal wattage to fiber and gives superior finishing. 

Fiber lasers 

In fiber lasers, a type of solid-state laser, the monochromatic and pumped, intensified light is directed and wave-guided down an optical fiber towards the cutting surface. The light is not passed through any gas for stimulated emission. 

The basic configuration of the optical circuit of a high-power fiber laser consists of three major sections: Pump section, Oscillator section, and Beam delivery section. 

In the pump section, the laser light from pumping laser diodes passes through optical fibers into a high-power pump combiner. The combiner couples the pump light from the laser diodes into a single-mode optical fiber. 

In the Oscillator section, the pump light from the high-power pump combiner propagates through a double-clad fiber. Regarding the beam delivery section, it is composed of an optical fiber, passing the laser light from the Oscillator section to a beam coupler. 

Choose the right laser cutting process and type for the expected result. 

What are optical isolators used for?

An optical isolator is a passive optical device designed to transmit optical signals in only one direction. It is primarily used to isolate the ports from unwanted optical reflections. The device is characterized by certain features, including:

  • Insertion loss
  • Degree of isolation
  • Return loss
  • Operating wavelength
  • Optical bandwidth
  • Requirements for input polarization
  • Maximum optical power

For instance: A 1480nm polarization-maintaining isolator is an optical isolator that operates at a wavelength of 1480nm, while maintaining the state of polarization.

An ideal PM optical isolator is characterized by:

  • Low insertion loss
  • High degree of isolation
  • High extinction ratio
  • High return loss
  • High precision
  • Wide attenuation range

While many optical isolators are used with free-space beams, others are coupled to waveguides, i.e. optical fibers.

What is an optical isolator used for?

1. Semiconductor laser: An optical isolator is mainly used for avoiding unwanted optical reflections, also called feedback. For example, a single-frequency semiconductor laser is highly sensitive to external optical feedback. Even a very low level of optical reflection can result in a substantial increase in laser phase noise, intensity of noise, and wavelength instability. That’s why an optical isolator is needed at the output of each laser diode in applications

2.  Fiber Amplifier: Another example where an optical isolator is needed is a fiber amplifier. In such amplifiers, we need unidirectional optical amplification. Bidirectional optical amplification due to optical gain medium can lead to self-oscillation if external optical reflections from connectors and other optical components are strong enough. The use of optical isolators is common among erbium-doped fiber amplifiers (EDFAs) deployed in lightwave systems.

3. Polarizers: Some tunable isolators are designed to adjust the angular orientation of polarizers and optimize the isolation for different wavelengths. In that way, a single device can be used to cover a broad wavelength region.

4. High-Power Applications: Some optical isolators can work at very high optical power levels and thus, are suitable to be used in high-power applications. These high-power optical isolators are used where optical damage may occur due to high peak powers.

5. Fiber Lasers: PM optical isolators are widely used in fiber lasers to avoid unwanted feedback and prevent the possible damage caused by optical reflections while improving amplification.

6. Fiber communication: Laser diodes that are used in fiber communication systems are susceptible to reflected light from the fiber. Hence, PM optical isolators play a great role in fiber communication systems.

The uses and applications of polarization-maintaining isolators are continually increasing as the demand for fiber lasers and fiber communications is increasing in the market.

How can high-power circulators increase network capacity?

As the demand for fiber optics networks is rapidly growing, more businesses and network service providers are looking for ways to increase the capacity of their networks. One traditional way to increase the capacity of a fiber network is to install more optical fiber cables. However, this can be extremely expensive and thus, limits the ability to cater to the increasing demand for more data and bandwidth.

However, the ongoing research and development in optical passive components have now made it possible to double the network capacity without installing additional optical fibers. The one small component that has made it possible to double the capacity of a fiber network is a high-power circulator.

What are high-power circulators?

High-power circulators are non-reciprocal optical passive components that route incoming optical signals from one port to the next port while blocking transmission from one port to the previous port. It can handle high levels of optical power and is specifically designed for high-power applications, including communication, fiber lasers, etc.

Some examples of high-power circulators are:

  • 100W 1064nm high-power circulators
  • 30W 1550nm high-power PM circulators
  • 10W 2000nm 3-port high-power PM optical circulator s

How do high-power circulators increase network capacity?

The use of high-power circulators provides the ease and convenience of doubling the transmission capacity of a fiber optic network without requiring optical fiber cables. High-power optical circulators are three-port, non-reciprocating, and unidirectional devices that help you achieve bidirectional propagation of light signals in a single fiber. Besides, they also result in obtaining low insertion loss and low crosstalk between two channels.

Typically, bidirectional optical links can be operated in full-duplex or half-duplex mode. In full-duplex, optical signals can be sent and received simultaneously. On the other hand, in half duplex mode, optical signals can be either sent or received but not both at the same time. A half-duplex transmission can be achieved by using either single or double fibers and a full-duplex transmission is implemented by using two fibers.

However, by using high-power circulators, bidirectional transmission can be done through a single fiber, thus, minimizing the amount of optical fiber needed and maximizing the transmission of optical signals over a single fiber.

As a result, it also helps eliminate the need for more powerful transmitters, more sensitive receivers, and more optical amplifiers, making the whole fiber network more economical. The cost is further reduced because high-power circulators can be obtained at cheaper prices.

To increase the isolation and extinction ratio of optical circulators, birefringent crystals, such as Terbium Gallium Garnet (TGG), are used to design these components.

Multi-port high-power circulators, such as 3-port high-power circulators, act as a roundabout for light where each input port is routed to exactly one output port in a non-reciprocal fashion. As a result, integrated circulators can double the network capacity in many data centers and telecommunication networks.

At DK Photonics, you can buy a wide range of high-power circulators, such as TTG-based 1064nm high-power circulators, 1030nm high-power circulators, 1080nm high-power circulators, and more. If you don’t find the specifications you need for high-power circulators for your application, please feel free to contact us.

Are 1064nm High Power Isolators are TGG-Based or Faraday-Based?

The 1064nm high-power isolators are small optical passive components that permit the light to travel in one direction only, operate at 1064nm wavelength, and are widely used in high-power fiber laser and amplifier applications. They help prevent any reflected light from going back to the source and hence, reduce feedback problems. These optical isolators are specifically designed to handle high power and hence, many high-power isolators can handle even a hundred Watts. On the other hand, low-power isolators can work with only 0.5 or 1 to 5 Watts.

Do high-power isolators use TGG or Faraday materials?

While some high-power isolators contain TGG crystals, others may have alternative Faraday materials. Take note that TGG crystals are also a type of Faraday material and they are the most common crystals used for optical isolators. Let’s find out what using TGG crystals and alternative Faraday materials means for high-power isolators.

What is TGG?

TGG stands for Terbium Gallium Garnet (Tb3Ga5O12). It is the most commonly used single-crystal Faraday rotator for optical isolator applications. Since TGG can melt congruently under the temperature of ~1825 degrees Celsius, large crystals of TGG can be easily made using the Czochralski technique. While one can easily grow these crystals in large sizes, bulk defects do not allow for fully utilizing these crystals. Some of these defects include color centers, dislocations, strain areas, etc.

TGG is widely used in 1064nm high-power isolators but it is very sensitive to increase absorption at this wavelength. Typical values for absorption at 1064nm for TGG range from 0.20 to 0.30%/cm.

What are Alternative Faraday Materials to TGG?

Since there are intrinsic limitations in the performance of TGG crystals, alternative Faraday materials are being explored and researched for delivering higher performance. The two great examples of alternative Faraday materials include lithium terbium fluoride (TLF) (LiTbF4) and potassium terbium fluoride (KTF) (KTb3F10).

These are small crystals that possess small non-linear refractive indices and thermo-optic coefficients, while also exhibiting Verdet constants similar to or near to those of TGG crystals. Hence, TLF and KTF are also being considered for making high-power isolators.

Contrary to TGG, these two single-crystal Faraday materials melt incongruently, which means they are difficult to grow. Besides, their growth is flux-type, precipitate inclusions and scatter-type defects are also present in these crystals unless their melt stoichiometry is done under a controlled environment. Among these two crystals, the most focus is given to KTF because of the stringent crystallographic alignment requirements.

Both of these materials exhibit improved absorption at shorter wavelengths. But, unlike TGG, color center formations and cation valence alterations are reduced in TLF and KTF. Therefore, they are considered promising for optical isolators for visible wavelength lasers.

However, nowadays, 1064nm high-power isolators that are made using TGG crystals are more common, affordable, and easily available, which makes them a a convenient choice for fiber lasers and various other applications.

At DK Photonics, we offer not only 1064nm high-power isolators but also various other high-power isolators that operate at different wavelengths. Besides, we also offer low-power PM optical isolators. So, whether you need standard optical isolators or custom optical isolators, get in touch with us.

Detailed Understanding Of PM Fiber Components

The demand for PM fiber components is increasing and is expected to increase beyond 2023, especially in the telecom and mobile industry. And there are many reasons for this increasing demand. First and most important, the performance of PM fiber components in different applications for different industries. The components, no matter how they are used, increase the efficiency and effectiveness of the processes used in. 

The PM fiber components are useful but many people still don’t know everything about them. And due to a lack of knowledge, they miss out on several benefits. 

In this post, we will discuss some important details about PM fiber components. 

What are PM fiber components?

With the strong built-in birefringence, the polarization-maintaining (PM) fiber is a special fiber that preserves the properly oriented linear polarization of an input beam. The optical fibers usually exhibit some degree of birefringence even when they have a circularly symmetric design. This happens because some mechanical stress or other effects that break the symmetry is always there. 

The polarization of light that propagates in the fiber gradually changes in an uncontrolled way and depending on wavelength. The uncontrolled way depends on any bending of the fiber and its temperature. For some fiber optic components, the polarization-maintaining feature is extremely important. One of those PM fiber components is modulators. 

What is the principle of PM fiber components?

The polarization state is preserved even if the fiber is bent because the polarization of light launched into the fiber is aligned with one of the birefringent axes. There is a strong principle behind this. 

The principle is understood as coherent mode coupling. The two polarization modes’ propagation constants are different because of the strong birefringence. This leads to a rapid drift away from the relative phase of the co-propagating mode. 

The difference between the relative phase of the co-propagating mode matters. Large differences impact the usual disturbances in the fiber. They vary too slowly to do effective mode coupling. 

What are the applications of PM fiber components?

The components are used in applications like fiber optic sensing, interferometry, and slab dielectric wave-guides. Other than this, they are used in telecommunications to connect source lasers and a modulator. Here, the modulator needs light as input. 

The components are used in transmission applications like transmission lines for optical sensors and coupling for optical-electrical integrated circuits. In these applications, the polarization plane of the optical signal is important. 

The components are used lithium modulators, Raman amplifiers, and other polarization-sensitive systems. These components help the systems to maintain the polarization of the incoming light and keep cross-coupling between polarization modes at a minimum. 

Where will you get the best PM fiber components?

Come to DK Photonics, where you will get all kinds of PM fiber components, including 80um PM fiber components. Other than this, you will get customized components, suitable for all your needs. 

Why Should Polarization Maintaining Filter Coupler Feature High Extinction Ratio?

A polarization maintaining filter coupler splits the light from an input PM fiber between 2 output PM fibers or combines light signals from 2 input fibers into a single PM output. Basically, the device is used to split high-power linearly polarized light into multiple paths without perturbing the linear state of polarization or SOP. Other than this, the device is used as a power tap to monitor signal power in a PM fiber system without disturbing the linear SOP of the light propagating in the PM filter. 

In the applications, you will find PM fiber interferometers, power sharing in polarization-sensitive systems, and signal monitoring in PM fiber systems. The package consists of rugged stainless steel, which is designed for high optical performance and stability. 

The polarization maintaining filter coupler features low excess insertion loss, low back reflection, and high extinction ratio. 

In this post, we will discuss one of the features of polarization maintaining filter coupler i.e. the extinction ratio, and why it should be high. 

Extinction ratio 

The extinction ratio quantifies the cross-coupling in regards to birefringent fiber. It indicates the amount of light that can mix between the two polarization axes. The value of the extinction ratio is important because it measures the polarization maintaining the performance of an optical fiber. 

Mostly, the extinction ratio is misunderstood by many people, leading to lots of problems in the future. 

The value of the extinction ratio depends on the length of the fiber and the environmental conditions in which you use it. If the fiber is subject to high mechanical stress and small-diameter bends, then internal disruption is possible, reducing the extinction ratio significantly. 

What’s the impact of extinction ratio on the system performance and other parameters?

With a high extinction ratio, the bit-error ratio or BER improves. And when the bit-error ratio improves, it reduces the number of errors and the amount of error correction required. The high data rates are pushed through materials, loss, and dispersion close the eye and errors increase. 

What happens if the extinction ratio is low or poor?

If the extinction ratio is low or poor, the polarization-maintaining filter coupler will increase its power penalty (PP), worsen its Bit-error ratio (BER) and diminish its benefit of increased power. 

When does the extinction ratio become significant?

If you want quality and successful performance of the maintaining polarization filter coupler, the extinction ratio becomes significant. 

Sometimes, the measured values between manufacturers and designers are very different. Even the end users obtain different values than the manufacturers. If this happens, the device will be rarely productive. So, the value of the extinction ratio should be determined before buying a polarization-maintaining filter coupler. And undoubtedly, it should be high. 

The Growing Demand for PM Fiber Components in 2023 and Beyond

The demand for PM components is continuously increasing, especially in the telecom and mobile industry. According to a report published at Mordor Intelligence, the market for fiber optic components is projected to grow at a compound annual growth rate (CAGR) of 10.7% during 2021–2026. The report attributes the fast growth of this market to the:

  • Increasing deployment of data centers
  • Growing internet penetration
  • Increasing data traffic
  • Rising demand for bandwidth and reliability
  • Advancements in the fiber optic component ecosystem

Factors that Propel Demand for PM Fiber Optic Components

  1. Data transmission is becoming more prevalent due to the popular trend of IoT and more connected things. It is projected that the total installed base of IoT-connected devices will increase by up to 75.44 billion worldwide by 2025. It clearly indicates a fivefold increase over a decade.
  2. The ongoing improvements and advancements in the telecommunication sector are increasing the rate of deployment of broadband network architectures. Fiber to the Home (FTTH) and Fiber to the Building (FTTB) are significant broadband networking architectures that require the deployment of fiber optic networks on a large scale.
  3. Another factor that is contributing to the growth of PM components is the introduction and increasing adoption of new applications such as wearable devices, IoT, and cloud computing. The Cisco Visual Networking Index reported that the number of connected wearable devices worldwide has increased more than two times over the last three years. In fact, the number of such devices was forecasted to reach more than one billion by this year. As a result, the fiber optic component market is seeing significant growth during the forecast period.
  4. Internet penetration and data traffic are increasing rapidly around the world, and this, in turn, increases the growth of data centers and the need for high-speed transmission networks. All of this is ultimately fueling the fiber optic component market, including PM components. For instance, Cisco Systems forecasted that there will be 7.2 million data centers in the world, generating an even-greater amount of data by 2021 and boosting the demand for fiber optics components.
  5. Amidst all this, the fiber laser market is registering positive growth at a CAGR of 11.1 between 2021 and 2031. Since fiber laser systems use various PM components, they are also propelling the growth of the fiber optic component market.

At DK Photonics, we offer a wider range of optical passive components, including 1.0μm PM components, 2.0μm PM components, 80μm PM Fiber Components, and more. Whether you need optical isolators, optical couplers, optical splitters, pump combiners, optical circulators, fused products, WDM & Filter products, or high-power PM components, we have got you covered. If you need any PM components with standard or custom specifications, please get in touch.

What is the importance of 80um PM fiber components?

The demand for 80um PM fiber components based on optical fibers is continuously increasing. With the advancement in optical integration toward complex systems, laser technologies are also continuously evolving. Due to this, such components are widely used in various application fields such as:

  • Telecommunications
  • Sensing and monitoring
  • Industrial tools
  • Metrology
  • Spectroscopy
  • Medical diagnostic instruments

In addition to the number of applications, the performance of PM fiber components is also expected to increase to keep pace and enable innovation in this field.

Main Issues When Dealing with Information Delivery via PM fibers

There are some important issues when dealing with the delivery of information over PM fibers. The major issues are:

  • How to preserve information over longer distances
  • How to quantify polarization performance

The first aspect is impacted by the quality of PM fibers and the performance of PM fiber systems is also affected by the function of the junctions when fibers are joined. The second aspect is associated with:

  • Evaluation of system’s polarization performance
  • Suitable characterization methods
  • Proper interpretation of measurement results

Challenges Faced by Standard Fibers

Standard fibers are too sensitive to fluctuations caused by a range of factors, such as:

  • Material inhomogeneity
  • Environmental changes such as temperature variations
  • Mechanical stress produced by fiber compression, bending, twisting, and stretching

Due to all these factors, it is difficult to preserve the polarization state when light travels through the fiber.

To mitigate the disturbances caused by these factors, birefringence is introduced into the fibers by incorporating stress elements into the fiber structure that compresses the core anisotropically.

By doing this, fibers become not only more resilient towards external disturbances but their radial symmetry is also lifted effectively.

Why Are 80um PM Fiber Components Trending?

The reason why 80um PM fiber components are becoming more popular than traditional 125um PM fiber components is that the thin diameter of PM fiber components (Φ80μm) has special characteristics such as:

  • No tension fused taper
  • On-line adjustment of main axes in polarization-maintaining fibers
  • High stability package

While 80um PM fiber components offer the same performance and extinction ratios as the 125um versions do, 80um versions are mainly designed for low bend loss at small bend diameters.

As a result, using 80um PM fiber components make it easier for users to reduce package sizes significantly and meet the demands of all current and future applications.

Thus, if you are facing challenges due to the large diameter of PM fiber components and higher bend losses, you should invest in 80um PM fiber components to mitigate such problems.

At DK Photonics, we offer a wide range of high-quality 80um PM fiber components for a variety of applications. For custom orders, please get in touch with us.