Category: FTTX

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. 

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.

What is a polarization maintaining filter coupler?

A polarization-maintaining filter coupler is an optical coupler that combines the light coming from the two input PM fibers into one output-PM fiber. This type of coupler supports the light wave of each polarization and doesn’t block any polarization. It also works as a splitter as it can also split the light typically into two ports. So, a PM filter coupler can work in both ways as a coupler and as a splitter.

It is basically designed to split high power linearly polarized light into multiple paths, without altering the state of polarization. You can also use it as a power tap for monitoring signal power flowing in a PM fiber system without affecting the linear SOP of the light traveling through the optical PM fiber.

 In a 1×2 PM filter coupler, the division of power occurs with a fixed proportion.

To suit the needs of different projects, there are various configurations available for polarization-maintaining filter couplers.

Different Configurations of PM Filter Couplers

The different configurations available for PM Filter couplers include but are not limited to:

  • 1×2 (one input/two outputs)
  • 2×2 (two inputs/two outputs)
  • 1×4 (one input/four outputs)
  • 2×3 (two inputs/three outputs)

How is the coupling ratio in PM Fiber couplers determined?

The coupling ratio of signals or splitting proportions depends on the PM Filter coupler’s configuration. A coupler ratio refers to the ratio in which input optical signals are divided between different outputs. For instance, with 50:50 coupling ratio in a 1×2 PM filter couplers, the optical signals are divided in equal proportion in two output-PM fibers. In such couplers, half of the input optical power is coupled to each port.

Other common coupling ratios include 90:10, 80:20, and 70:30. With these coupling ratios, a PM filter coupler doesn’t couple equal power to both the output-PM ports. For instance, in a PM filter coupling with an 80:20 coupling ratio, 80% percent of optical power is sent to one output PM fiber and 20 percent of the remaining optical power is directed to another output PM fiber.

Thus, you can easily design your optical fiber architecture as you have optical filter couplers with different configurations and can send optical power depending on whether you are sending it to the end-point or another device from where the optical power needs to be split further.

What should I know before choosing PM filter couplers?

First of all, you need to know the desired coupling ratio of PM filter couplers. Then, you need to check other parameters such as insertion losses, optical return loss (directivity), and excess loss. If an application involves differences in the polarization states, then you also need to analyze the polarization-dependent loss.

If you need polarization-maintaining filter couplers for applications such as PM fiber interferometers, power sharing in polarization-sensitive systems, signal monitoring in PM fiber systems, or fiber optic instruments, please get in touch with DK Photonics.  

A Definitive Guide to Faraday rotation

Introduced by Michael Faraday in 1845, the Faraday rotation or Faraday effects is a magneto-optical phenomenon. The phenomenon means an interaction between light and a magnetic field in a medium. 

Faraday rotation was not a direct development by Michael Faraday. He was searching for experimental evidence that the forces in nature were interconnected. In this process, he made a remarkable discovery by carefully examining the polarization of light when it passed through a transparent material in the presence of a magnetic field. It was observed by him that linearly polarized light propagated through matter parallel to a static magnetic field, causing a rotation of the plane of polarization. Here, the effect was very small. But, with his knowledge and experience, Michael Faraday identified the phenomenon, which is known as Faraday Rotation or Faraday Effect. 

Generally, the Faraday rotation occurs in optically transparent dielectric materials, including liquids, under the influence of magnetic fields. 

What is the physical interpretation of Faraday rotation?

The linear polarization that rotates in the Faraday Effect consists of the superposition of a right and left-circularly polarized beam. The direction of the electric field rotates at the frequency of the light in a clockwise or counter-clockwise direction in the circularly polarized light. 

When you use material, the electric field causes a force on the charged particles known as electrons. The motion effect is circular, circular moving charges creating their own magnetic field along with the external magnetic field. 

This creates two conditions: one, the created field is parallel to the external field for one circular polarization and in the opposing direction for the other polarization direction. Here, the net field is enhanced in one direction and diminished in the opposite direction. This leads to dynamic changes in the interactions for each beam. One of the beams slows down more than the other, causing a phase difference between the left and right-polarized beams. When the two beams are added after the phase shift, it results in a linearly polarized beam with a rotation in the polarization direction. 

The physical properties of the material affect the direction and the intensity of polarization rotation. 

Which devices are based on Faraday rotation?

Faraday isolator- Faraday rotation is needed in Faraday isolators to protect lasers and amplifiers against back-reflected light. For the right use in Faraday isolators, the rotation angle should be close to 45 degrees in the spectral region of interest. It’s said a large attenuation for back-reflected light is obtained by a highly uniform polarization rotation. 

Ring laser resonator– In a ring laser resonator, a Faraday effect or rotation is used to introduce round-trip losses, depending on the direction. This enforces unidirectional operation. A Faraday rotator provides only a very small rotation angle but it’s sufficient because a very small loss difference is considered sufficient.  

Faraday mirror– When a 45-degree rotator combines with an end mirror, it forms a Faraday mirror. A laser beam sent through some amplifier, then reflected at a Faraday mirror and sent back through the amplifier has a polarization directional on returning, which is orthogonal to that of the input beam. This happens even if the polarization state is not preserved within the amplifier. 

Faraday rotation is a big achievement in the science industry. If you want to get devices that are based on Faraday rotation, connect with DK Photonics. 

What Is a Faraday Mirror and How Does It Work?

Faraday mirrors

A Faraday Mirror is a fiber optic polarization rotator mirror that is used for making a wide range of passive fiber optics components. It is an important invention that made it possible to create passive polarization-maintaining components.

Earlier, the main issue was to maintain the state of polarization as the beam travels across the fiber. This can be easily achieved by using a polarization-maintaining (PM) fiber which is designed for the very same purpose. However, PM fibers and PM-fiber-based devices used to be extremely expensive for many applications and were also difficult to handle.

An optical beam that travels in a typical single-mode (SM) fiber undergoes random changes in birefringence due to stress, vibration, or temperature variation. The use of the Faraday rotator mirror can help resolve this issue.

What is a Faraday mirror?

A Faraday mirror is a fiber optic device that can be used for both the reference mirror and the probing mirror. It works as a phase conjugate mirror by introducing a phase delay of 90 degrees. This feature allows the mirror and the return path of the optical beam to compensate for any induced birefringence automatically.

What is a Faraday mirror made of?

A high-quality Faraday mirror is made of Terbium Gallium Garnet (TGG). TGG is a crystal that is currently the best magneto-optical material for Faraday rotators and isolators. It is considered best because of the high Verdant constant and superior Faraday Effect. It has a higher thermal conductivity and high resistance to laser damage.

How does a Faraday mirror work?

A Faraday mirror works based on the Faraday Effect. In this device, a non-reciprocal rotation of a polarization state occurs as the light beam passes through a special optical medium under the effect of the magnetic field. We will discuss its working with the help of Faraday rotator as its main application is this device.

A Faraday rotator mirror (FRM) consists of a fiber collimator, Faraday rotator, and mirror.

As the orthogonal wave light components pass the optical fiber in the forward direction, they will experience a rotation of 45 degrees in the clockwise direction. When they are reflected by the mirror, they pass the Faraday rotator again, which is a non-reciprocal device, and the polarization state of the reflected optical signal will experience a rotation of another 45 degrees in the same direction as the input signal. Hence, the resultant rotation is 90 degrees. Now, the orthogonal components pass the fiber back but in a complimentary fiber axis and you obtain a linearly polarized light on the close end of the fiber with a rotation of 90 degrees.

Do you need Faraday mirrors to manufacture your fiber optics components or for your research projects? You can easily buy it online at DK Photonics.

Features and Applications of 780nm Optical Isolators

The high-power dual-stage optical isolator 780nm is a polarization-independent fiber element that enables all polarized light to propagate in one direction while blocking it in the opposite direction.

It is not possible to adjust the polarization of input light in many applications. In such instances, a polarization-independent optical fiber isolator with a wavelength of 780nm is required. 780nm optical fiber is a critical component that protects lasers, amplifiers, and ASE sources from instabilities caused by spurious back-reflected light.

Overview of the 780nm Optical Isolators

Low-power lasers benefit from the flexibility, convenience, and performance of the I-780-LM compact designs. I-780-LM covers the wavelength range of 770 to 790nm. A Faraday rotator constructed of LPE film is included in this design.

Due to the absorption of the Faraday rotator material, this type is only advised for low-power applications. For OEM requirements, metal-bonded or hermetic construction alternatives are available. I-780-LM has a standard wavelength of optimization of 780nm.

Applications

  • Semiconductor Laser Modules
  • Tunable Laser Modules
  • Small Form Factor Laser Modules

Features

  • Low Insertion Loss
  • High Isolation
  • Micro-Miniature Size
  • Broad Bandwidth
  • Wide temperature range
  • Polarization alignment

Single Mode / Single Frequency Laser Diode, 780nm DFB, 4mW

The DFB laser is made with discrete-mode (DM) technology, which results in a low-cost laser diode with mode-hop-free tuneability, high SMSR, and a narrow linewidth.

These laser diodes come in a variety of wavelengths ranging from 776 to 784nm, making them ideal for Rb-based atomic clocks, Rubidium sensing, and interferometry applications.

The fiber-coupled butterfly package includes a TEC and a thermistor for precise temperature and wavelength control.

780nm for Rubidium-Based Atomic Clocks

These 780nm lasers operate reliably and without mode hop over a broad wavelength tuning range. These Rubidium-based atomic clocks and spectrometer lasers have a single longitudinal mode. The low linewidth output is ideal for high-performance applications in a variety of environments.

Polarization-Independent Dual-Stage Optical Isolator Fundamentals

The polarization dependence of dual-stage optical isolators using polarizers and a Faraday rotator is a severe problem. The insertion loss will rise as a result of this problem. As a result, optical isolators that are not polarization-dependent are particularly appealing for transmission systems.

By replacing the polarizers with polarizing splitters combiners, it is possible to achieve a polarization-independent design: they divide the input light into two orthogonal states of polarization that run through the Faraday cell separately to experience isolation and are recombined at the output.

Many applications in fiber optic systems necessitate high-power polarization-independent dual-stage optical isolators, which allow inputs with any polarization direction to flow through without PDLs while isolating back reflections (return lights).

The high-power dual-stage optical isolator is a vital component in optical systems. High-power dual-stage optical fiber isolators are used to ensure that laser transmitters and amplifiers are stabilized, and that transmission performance is maintained.

Can an Optical Splitter be Used as a Combiner?

It can be challenging to tell the difference between a Combiner and a Splitter because they have similar appearances. Furthermore, some splitters and combiners might be passive or active, powered or unpowered, adding to the confusion.

Let’s look at the combiner and splitter to see what they’re for.

A Combiner

A combiner is a device that combines multiple input signals of varying frequencies into a single output signal for feeding a single antenna. A combiner basically takes all of the signals and combines them, which is useful when the signals are meant to be combined.

A Splitter

On one end, splitters have a single connection and numerous connections on the other. A splitter receives one signal and splits it into two.

While signal splitting may appear to be the most convenient approach to adding more outlets, keep in mind that each time a signal is split, its power is halved. When you split the transmission, you’re sending half as much signal through each line.

You may think you have a good signal now, but if you divide it too many times, it won’t accomplish the job. Before deciding to split the signal, you need carefully assess whether you have a strong enough signal.

It is frequently recommended that two antennas be used instead of a splitter in places where the signal is extremely weak. The signal will always be divided, whether or not two devices are connected to the splitter.

Polarization Beam Combiner/Splitter

This device can function as a polarization beam combiner, combining light beams from two PM input fibers into a single output fiber, or as a polarization beam splitter, splitting the light from one input fiber into two orthogonal polarization states output fibers.

Polarization Beam Splitter/Combiner

Polarization division multiplexing or demultiplexing in optical systems to boost transmission capacity is an important application of this device. Furthermore, as a pump combiner in optical amplifiers, the device efficiently combines the output from two pump lasers into a single fiber, increasing the optical amplifier’s saturation power and reducing its polarization sensitivity.

The device’s wide operation bandwidth and strong power-handling capacity make it ideal for next-generation amplifier systems. Finally, this compact device has a durable stainless steel package built for strong optical performance and stability, and it has low excess insertion loss, low back reflection, and a high extinction ratio that are comparable to or better than others on the market.

Features:

  • Compact size
  • Low insertion loss
  • High-capacity handling
  • Rugged design

Applications:

  • Mux/DeMux polarisation division
  • Raman amplifiers and EDFA
  • Laser Fiber Systems
  • Fiber Sensor Systems
  • Instruments
  • R&D Laboratories

Polarization Beam Splitter/Combiner is available from DK Photonics, a reputable optical passive component manufacturer based in China. Contact us if you are interested in purchasing Polarization Beam Splitter/Combiner.

What is a band-pass filter used for?

Fiber bandpass filters are the optical filters that allow optical signals of certain frequencies to pass through while blocking the optical signals of other frequencies. To block the light of unwanted frequencies, they either absorb the light or reflect it or do both. You can use a band-pass filter to transmit signals in a specific range of frequencies, varying from a narrow band to a wide range.

An Overview of a Band-Pass Filter

Optical bandpass filters are micro-optics devices that transmit (or pass) a specific range (or band) of frequencies and block others. This specific range can include visible light, as well as non-visible wavelengths that fall at the infrared and ultraviolet ends of the spectrum.

Since the filter passes only a certain band of frequencies, the result is an output that comprises only light signals with desired frequencies and wavelengths.

You can define them through various characteristics, including:

  • Blocking level – how effectively and efficiently the bandpass filter is able to eliminate the unwanted wavelengths
  • Peak Transmission – how effectively the incident light is propagated and transmitted
  • Central Wavelength – the wavelength of the light at the center of the transmission band profile
  • Full Width at Half Maximum – the limits of bandwidth between which 50 percent or more light is transmitted

For instance, a very high transmission across the FWHM range with a very low transmission outside of that range is an indication that a bandpass filter is highly effective and has very little noise in the output.

What is a band-pass filter used for?

A fiber bandpass filter is used for blocking unwanted noise signals in a wide range of systems and applications, such as:

  • Fiber amplifiers
  • Fiber lasers systems
  • EDFA systems
  • DWDM systems
  • High-speed communication system
  • Instrumentation applications

Apart from this, optical bandpass filters are also used for anti-reflection and anti-glare coatings, chemical analysis, dielectric mirrors, high reflectors, IR applications, fluorescence filters, long-wave pass, shortwave pass, UV applications, and more.

Generally, bandpass filters are made in two ways. Thin-film filters and coated filters are designed through the deposition of multilayer dielectric coatings onto a substrate. On the other hand, spectral and absorption filters are made by a combination of lamination, cemented layers, and thin film coating.

Fiber bandpass filters are designed based on environmentally stable thin-film filter technology. They work by absorbing or reflecting unwanted wavelengths and transmitting only desirable parts of the light spectrum.

By combing filters and different methods, it is possible to design single laminated bandpass filters with very specific and complex properties to meet the needs of all kinds of electro-optical applications.

DK Photonics is an esteemed optical passive component manufacturer based in China, offering a wide range of fiber optics passive components, including fiber bandpass filters characterized by high isolation, low insertion loss, high extinction ratio, and excellent stability. To buy fiber bandpass filters with standard or customized specifications, please get in touch with us.

Do Fiber Optic Cables Need Amplifiers?

Fiber optic cables are playing an essential role in creating highly reliable and high-performing optical communication systems and networks. When a signal propagates in a cable for a long distance, it becomes essential to install amplifiers in the network to prevent any distortion or weakening of the signal. In the same way, when light (or optical) signals travel in a fiber optic cable over a long distance, it also needs a fiber in-line amplifier to restore the strength of the light signal. Let’s learn about fiber optical amplifiers in detail.

What is a fiber optical amplifier?

A fiber optical amplifier is a special device that is specifically designed to boost (amplify) light-wave signals traveling across fiber optic cables without changing these signals into electrical form.

The use of optical amplifiers in optical fiber communication applications allows you to retain the optical integrity of the whole system.

What is the need for a fiber optical amplifier?

Wherever data is transmitted in the form of optical signals through a fiber cable, you need a fiber optical amplifier to preserve the strength of optical signals. Typically, when signals are sent from one end to another, then the quality and strength of the signal degrade due to various factors. If a fiber optical amplifier is not used and a degraded signal is sent to the other end, it becomes difficult or sometimes even impossible to regain the original information sent via that particular signal.

Since optical signals carry information in an optical communication network, the use of an electronic amplifier is not preferred; otherwise, some additional units will be needed to convert optical signals into electrical signals and then again need to convert the electrical signals into optical signals after amplification. This process is not only time-consuming but also makes the entire system more expensive and labor-intensive. Plus, data transmission will also be slower.

Therefore, fiber optical amplifiers are installed to amplify optical signals so that data signals can be transmitted at a faster rate and the integrity of data and information carried by signals remains intact.

In short, optical amplifiers allow you to transmit signals over long distances and at a faster rate without any attenuation or distortion.

Different Types of Optical Amplifiers

Optical amplifiers are usually categorized into three categories, namely:

  • Semiconductor amplifiers
  • Doped fiber amplifiers
  • Raman amplifiers

Among all these three amplifiers, doped fiber amplifiers are more commonly used in fiber communications, fiber laser, and fiber sensor applications. Abbreviated as DFA, the active medium of a doped fiber amplifier is created by doping silica core slightly with rare earth elements, usually erbium. Hence, doped fiber amplifiers are popularly known as erbium-doped fiber amplifiers (EDFA).

Sometimes, optical amplifiers are also used in long-distance optical communication networks, optical fiber distributed sensing, and fiber laser applications. These amplifiers are based on the principle of Raman scattering and don’t need the population inversion mechanism for amplification purposes. To amplify signals, these amplifiers utilize standard transmission fiber cables.

DK Photonics is a world-class optical passive component manufacturer based in China and its offerings also include high-quality and reliable fiber optical amplifiers that are widely acclaimed for achieving high gain and low noise amplification. For any queries related to fiber amplifier orders, please get in touch with us.