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What Are Optical Circulators And Their Applications?

Each optical circulator is a generalized isolator which has three ports or sometimes more. Where an isolator causes the loss in the direction of isolation, a circulator gathers the light and redirects it to an output port which is nonreciprocal.

If I talk about a three-port circulator with non-strict-sense, this type of circulator has significance use in telecommunication applications because it is not necessary that the light should travel back from port 3 to port 1. For example, the light reflected from a fiber Bragg grating requires to be separated from the input light without loss, but since optical links are not operated in reverse only, there’s no requirement of strict-sense behavior.

An optical circulator is a special kind of fiber optic device which can separate optical power traveling in one single optical fiber in opposite directions. A polarization insensitive optical circulator can be used here to get bi-directional transmission of power over a single fiber. This circulator is majorly used in modern communication systems and advanced fiber-optical sensor systems due to its high isolation between the input power and reflected optical power and its lower loss of insertion.

A majority of online suppliers offer three or four-port optical circulators with;

Standard 1310nm or 1550nm windows

Or sometimes a wider range of wavelength from S to L band

Some of the manufacturers can also provide customized circulators on special requests with providing different wavelength, for instance, 1030nm, 1050nm, or 1040nm can be requested.

Though the standard power handling of this kind of a circulator is 300mW (CW), in the market, circulators are also available with power handling 1000mW, 2000mW, and 500mW (CW).

Here, a buyer requires being fully aware of the requirements of the application before choosing one.

Features

Low Insertion Loss

Low PDL

Wide Band, High Isolation

Epoxy Free Optical Path

Compact In-line Package

High Stability and Reliability

Easy mounting

The polarization insensitive optical circulators are often easily mounted to optical tables and can withstand various handlings. The use of four strong magnets helps to hold the rugged package securely on surfaces. Another mounting option is to wisely use tow countersunk holes with having some space in-between, in order to achieve compatibility with mounting patterns of optical tables.

Major Applications

Optical Amplifier

Fiber Sensors

Add-Drop Filters

Bi-Directional Communications

Metro Area Network

Digital, Hybrid, and AM-Video System

Wavelength Add / Drop

Dispersion Compensation

EDFAs

The online market is actually full of such optical circulators and buyers can place an order for customized circulators too, for instance, pigtailed versions of circulators would be perfect if an application requires a fiber with extended length on the circulator’s input and output.

Once you go online you will find that there are several suppliers of these optical circulators. You require making a decision on which one you should choose to shop. Apart from that, gather complete information about the application’s requirements and then decide which one you should buy.

These Are Proven Tips That Will Help Quickly Find the Best Optical Circulator

There are many brands in China making a wide range of optic fibers or circulators – a crucial device widely used for electronic applications. What that makes it a bit complex to choose the best one (optical circulator) is that all of them claim to offer high quality products for the most competitive prices. To help you with that, here we have curated a list of some tips that are very effective and anyone can apply them to select optical circulator.

 Tips to Choose an Optical Circulator

Look for all the options

 There are many options that you will find in China when it comes to optic fibers. For example Polarization Insensitive Optical Circulator one of the most widely used optic fibers for a wide range of electronic applications. The circulator is packed with host of features. If you are looking for an option that is durable, affordable and provide high quality performance, Polarization Insensitive Optical Circulator is what you must consider.

 Check after sales support

Whatever option you choose, make sure the supplier you buy your Polarization Insensitive Optical Circulator provides a good sale support. So when you have any problem with the product, you do not need to hire a technician. You can call to the supplier who will provide the right assistance to solve your problem. So buying Polarization Insensitive Optical Circulator from such a supplier saves you a chunk of money you need to pay for hiring a technician.

The suitability of the fiber to your device

As optic fibers come with different features, and so are suitable for some certain types of devices, it is vitally important to make sure the Polarization Insensitive Optical Circulator you buy is compatible with your device.

Compatibility

Types of fiber optic transceivers are getting richer, but the compatibility between different types has a great impact on the quality of network. It should be known that this product is designed to meet related international standards. Because. The circulators meeting international standards have no issues of compatibility.

Temperature adaptation

The temperature which is generated inside fiber optic transceivers is low, but as they are used in the Switches and computer room, the temperature fluctuates. It may get higher or lower. Too high or too low temperature adversely affects the parameters, for example optical power, optical sensitivity, etc. Polarization Insensitive Optical Circulator seems a best choice in this case. It is highly sensitive to fluctuation in power, and quickly adapts to the temperature.

 When you need to buy optic fibers, follow these tips that will surely profoundly help you choose the right circulator for you.

Optical Circulators and Its Passive Optical Components

To fulfill the requirement of communication efficiency, network technicians generally use optical circulator in a fiber optic system as it reduces the loss of light. An optical circulator is a small yet powerful device used in optical communication systems. The device is typically used to separate optical signals that (in an optical fiber) travel in opposite directions.

Functioning Principle and Components

Optical circulators usually consist of a polarizing beam splitter, Faraday rotator, reflector prism, birefringent blocks, and a retardation plate. The functioning of an optical circulator is a little similar to optical isolator. A light which travels in one direction right through the Faraday rotator will have its polarization rotated in one specific direction. A light that enters the rotator from the opposite direction will have its phases rotated in the opposite direction (sometimes may depend upon the propagation direction of the light).

In other words, light always rotates in one direction in accordance with the rotator regardless of its traveling direction.

Three-port optical circulator is widely used so let’s discuss that first. A signal in a three-port optical circulator is transmitted from 1st port to 2nd port where another signal is transmitted from 2nd to 3rd and additionally, a third signal can also be transmitted from 3rd to 1st.

Types

As per the Polarization Characteristics

If we talk about the characteristics based on the optical circulator’s polarization capabilities, they can be divided into two major types:

PM – Polarization Maintaining

PI – Polarization Insensitive

Each PM optical circulator typically comes in the market with a polarization maintaining fiber which makes it an ideal component for applications where it is necessary to maintain polarization, for example, Raman pump applications, 40Gbps systems, etc.

Polarization insensitive optical circulator is a small lightwave component which delivers high-performance functioning. The component comes in the market having features like low insertion loss, high isolation, high stability and reliability, and low polarization-dependent loss (PDL).

It is high in demand in combination with fiber gratings and other reflective components in close-packed wavelength-division multiplexing (DWDM) systems, high-speed systems and bi-direction communication systems.

As per the number of ports availability

Optical circulators fall into three main types when it comes to the number of ports:

3-port

4-port

6-port

3-port and 4-port optical circulators are commonly used way more than the 6-port optical circulations. In such circulators, optical light that is transmitted from any port can easily be redirected to any other port, regardless of the port-type.

An optical circulator is very commonly applied in a long list of applications within a fiber communication system. In modern optical communication systems, the optical circulator is usually used for wavelength division multiplexing networks, optical time domain reflectometers, fiber amplifier systems, bi-directional transmissions, etc.

With primary characteristics such as high isolation, low crosstalk, low insertion loss, and large bandwidth, the optical circulator can also become an in-built component of the same device as transmitters, amplifiers, and receivers.

Achieving highly precise polarization is Easy like Never Before with Insensitive Optical Circulator

There are applications like optical fiber communication networks, fiber optic instruments, and depression compression modules wherein it is vitally important to polarize the lights going in multiple directions into one single direction. Thanks to Insensitive Optical Circulator, it is now pretty possible to achieve the polarization of light into single direction.

Optical circulator is specially designed fiber optic device with an ability to separate optical power traveling in opposite directions in one optical fiber. The optical circulator can also be used to achieve bi-directional transmission over a single fiber. The high isolation between the input and reflected optical power and low insertion loss makes the circulator highly suitable for the use in advanced communication systems and fiber-optical sensor systems.

Besides being highly capable of controlling the light flowing into different directions and directing it into a single desired direction, the insensitive optical circulators have hosts of other qualities that make it much the best choice for fiber optic device. They are:

  • Low insertion loss
  • High isolation
  • Ultra-low PDL and PMD
  • Epoxy-free optical path
  • Special operating wavelengths

The optic circulator provides high reliability and excellent optical performance. The device’s high isolation properties make it ideal for applications in telecommunications, fiber optic sensing, bio-medical, and photonics research.

The circulators com with different ports, for example three or four ports that cover standard wavelength rang. Also, it is possible to customize the wavelength according to different needs. For example, you can get circulators with wavelength ranges such as 1030nm, 1040nm, and 1050nm.

There are various brands making insensitive optical circulators. This means there are a wide range of makes of such optic devices available in the market. They all have features that almost identical but this does not mean they also have the same performance. The process they are built and quality of the material used is factors that play a vital role in the performance of an optic circulator. In addition, other things that should be considered before making the final buying decision are like:

  • Rugged, compact design: Rugged, encased design utilizing bulkhead connectors rather than loose pigtails reduces the fragility of the fibers from tangle and handling.
  • That is easy to install or mount: Choose the one that is easy to mount with optical cables. Four strong magnets hold the rugged package securely onto steel surfaces.
  • Pigtail circulators for the applications that require a length of fiber on the input and output of the circulator.
  • And the price of the circulator

DK Photonics Technology Limited is a leading and one of the top companies providing high quality optical passive components that are widely used for telecommunication fiber sensor and fiber laser applications. If you are looking for quality insensitive optical circulators for the most reasonable price, you can count on DK Photonics Technology Limited.

Things That You Must Know about Polarization Maintaining Optical Circulator

Optical fiber is used for an electric device in which light polarization is required. And each fiber is designed to do a certain job and so is suitable for some certain applications. So you should have the knowledge of an optical fiber that you want to buy and make sure the fiber you want to buy would be perfect for your need. So we have gathered some crucial information about optical circulator used for maintaining light polarization, and that will help you choose the right fiber.

If you are looking for a circulator for devices like fiber amplifiers, fiber sensors, test and measurement appliances, coherent detecting appliances, The 1310nm&1550nm 3-port Polarization Maintaining Optical Circulator with both axis working would be the best choice. The circulator is compact and very efficient to route the incoming signals from Port 1 to Port 2, and incoming Port 2 signals to Port 3. The circulator works as a single that can be used to transmit light from an input fiber to an output fiber. It directs the light returning from the output fiber to the third port. The 3 port circulator with both axis working is like an isolator that protects the input fiber from return power but the light that is rejected can be used.

Another fiber can be also used for those applications is 3 port optic circulator with fast axis blocked. This type of circulator is also lightweight, compact and performs well. This circulator also works as the circulator (with both axis working) does. Both circulators used for maintaining polarization can handle the power ranging from 300mW to 20 W, and have center operating wavelengths ranging from 850nm to 1650nm.

Both optical circulators (with both axis working and with fast axis blocked) provide a host of benefits such as low insertion loss, high isolations, etc. Here are some key benefits that the circulator provides:

  • Low Insertion Loss
  • High Isolation
  • High Extinction Ratio
  • Low Cost
  • High Stability & Reliability

Apart from those two circulators that are widely used for a wide range of applications, there are other optical fibers that are used for electric devices. Whatever fiber you buy make sure it works perfectly with your device.

So before you start looking for optical fibers, get to know about your device in details. Learn everything that can help you in a way or so to decide on which type of optic fiber you should look for.

Once you are done with the type of fiber you need, find a Polarization Maintaining Optical Circulator supplier. There are many Polarization Maintaining Optical Circulator suppliers in China, you should trust only those that are reputed and have long been into the business.

Optical Fused Coupler: Advantages and How to Buy the One Best For You

A fiber optic coupler is a crucial part of most electric devices wherein signals need to be converted from input to output. Without couplers, those electric devices have no importance, they are useless. So it is vitally important to wisely choose a coupler as to achieve the desired result.

What Is An Optical Coupler?

An optical coupler is a sort of device used for coupling light from at least two input fibers into one output fibers. The coupler consists of an input section with an output end face at one end of the bundling-length of input fibers and an output section that has an output fiber to confine the region to confine the light propagated in the input fibers and a surrounding cladding region.

When it comes to coupling light or let’s say, converting input lights from different fibers to a single output fiber, optical fused coupler remains one of the best options.

Advantages of Fused Couplers

Fuse coupler has many advantages. And one is that the output section comprises an optical fiber which can be made in appropriate lengths and which can be easily tapered.  This means the component can be made into two separate functional units. And this is a great advantage with the optical fused couplers.

Some other crucial benefits that a fused coupler offers include:

  • Tapering of the input fiber bundle can be dispensed
  • Output fiber can be made on a fiber drawing tower in long lengths with excellent production reproducibility.
  • Tapering can either be done during fabrication of the output fiber or after its fabrication
  • Another benefit is that the light in the tapered output section will never reach a surface or an interface that can have contamination due to handling.
  • Output fiber (including the confining region and a surrounding cladding region) is tapered down.
  • Higher longevity.
  • And affordable

Besides, there are many other benefits that you will discover later.

Choosing an Optical Coupler

There are different types of couplers used for optic fibers. With different features, each of them is best used for a certain goal. So it is important to choose a coupler that is perfect for what you want it to do.

So first get to know what you want, and with what kind of electrical device you want to use it for.

Now, you should search for options available. There are manufacturers that make couplers for optical fibers. But it is advisable to go with the one who is widely renowned as well as affordable. So take the time and do a market research to know what the options are and what those options offer so you can make the right decision.

Optical Circulators and Their Applications

The ‘optocirculator’ commonly known as optical circulator is the circulator which is majorly used for optical communication. It is actually similar to the isolator but, optical Isolator is used to insert resistance to the reverse signal with loss of insertion whereas, optical circulator directs the light to one port and diverts it out to the non-reciprocal port. Isolator typically has 2 ports only while circulator has 3 to 4 ports.


Originally, polarization insensitive optical circulators were used in telecommunication systems in order to increase the capacity of transmission of existing networks. The Utilization of these circulators in a bi-directional transmission system can double the network’s transmission capacity without deploying extra fibers, earlier, this task was very expensive without optical circulators.

However, the uses of optical circulators have greatly expanded in not only the telecommunication sector but also the imaging and sensing industries with the quick and great advancement in optical communication technologies and the wide availability of high-performance circulators at lower costs. Optical circulators have now become a vital element in advanced optical networks.

Typical Specifications for Optical Circulator:

  • Grade type (P or A)
  • Number of Ports (3 or 4 ports)
  • Insertion loss (0.6/0.8) over +/- 20 nm bandwidth
  • Central Wavelength (1310nm or 1550nm)
  • Directivity (60 dB)
  • Power handling limit (300 mW)
  • Isolation (min.40dB)
  • Return Loss (60 dB)
  • PDL (0.1 dB)
  • WDL (0.2 dB)
  • PMD (0.1 ps)

Optical circulators are intensively powerful devices that are generally used to extract optical signals from a reflective device. In this manner, optical circulators are regularly utilized related to the fiber Bragg gratings that are ordinarily reflective devices. Together with fiber Bragg gratings, optical circulators have turned out to be one of the vital components in advanced DWDM optical systems. Circulators are utilized as MUX/DEMUX systems, but at the same time are utilized in dispersion compensation with the fiber Bragg grating, tunable optical Add/Drop, and other different applications.

The idea has been adapted into different devices, such as replacing the coupler and erbium-doped fiber with a dispersion compensation fiber to reduce the required fiber length and adding a Faraday rotator in-between the fiber and mirror in order to reduce the polarization-induced effects. Also, bi-directional fiber amplifiers are also proposed for taking full advantage of the polarization insensitive optical circulator.

With the improvement in advanced optical systems, the uses of optical circulators are extending quickly and new uses and applications are rising rapidly. For instance, as of late it has been accounted that by including wavelength-specific capacities into circulators, a bi-directional wavelength-subordinate circulator can be arranged, which opens another measurement of uses in the advanced DWDM optical systems.

These circulators are widely used for several other applications and this why they are extensively available at the stores as well as online. Due to increase in demand, there are thousands of manufacturers and millions of suppliers of optical circulators all around the world.

Fused Coupler: The Best Way to Perfectly Achieve Light Polarization

Light polarization is very crucial for many applications such as optical sensors and optical gyro. The polarization ration varies, depending on the application. For example, optical sensors and optical gyro requires high polarization extinction ratio.

There are different types of couplers available in the market. And each of them functions in a certain way. This means that a polarization coupler is designed to do a particular job. So the coupler you choose should be based on your requirement. If you have devices that requires high polarization ratio, fused PM coupler would do the job well. Or you can go with standard couplers readily available in the market.

What is polarization?

When the light goes into multiple directions, the light is not polarized. A device called coupler is used to control the directions of the light and lead it into a single direction. When the light is controlled into a single desired direction, it is polarized.

So the PM Fused Coupler is designed so, it can be used to split high power linearly polarized light into multiple paths without perturbing the line are state of polarization (SOP). The couple is also used as a power tap that allows you to monitor signal power in a PM fiber system without interfering with the line of SOP of the light passing through the PM fiber. The fused coupler has many applications. But most prominent ones include interferometers, power sharing in polarization sensitive systems, and signal monitoring in PM fiber systems.

Other applications of fused coupler include:

  • Fiber Optic Instruments
  • Fiber Amplifiers
  • Fiber Sensors
  • Coherent Detecting
  • Research

So if any of these is what you are looking for a polarization coupler, then it is the fused coupler that you should go with. And this is because, compared to other options, the coupler comes equipped with far better features. Here are some of them for you to have a look at.

  • Low Insertion Loss
  • High Extinction Ratio
  • Compact In-Line Package
  • Available for Slow or Fast Axis Operation
  • High Stability and Reliability

In fact, fused coupler has numerous benefits that you can see as you use it for light polarization and maintaining an optimum polarization. So to know more how fused couplers are best to maintain light polarization, all you need to do just get the one.

There are many suppliers of couplers in China. You can find a fused coupler with them. So all you should do is search for the coupler suppliers in China. And you can do that with little effort provided you have the internet access. Most renowned suppliers own a website as the part of the effort to build a strong online presence. But make sure you buy fused coupler for polarization maintaining from the supplier and of the make having a good reputation in the market and also provides a reliable customer support. So in case you have any problem later, you can get it fixed easily.

Fused Coupler: Best Polaroid Filter for Maintaining Light Polarization

Achieving polarized light is very crucial and the quality of end results highly depends on the precision in maintaining polarized light. So it is very important to carefully choose the Polaroid filter that helps you achieve polarized light perfectly. And Fused Coupler would make the best choice for you.

 Let us take a snap look at the polarization

Light is a type of electromagnetic wave, consisting of oscillating electrical fields called as E, and magnetic fields, called B. Light waves go in many directions and when the light goes in different directions this means the light is unpolarized. But when it is vibrating one single direction, the light is polarized. A certain device that is used to polarize the light is called coupler or Polaroid filter which comes in different types and make like fused coupler most widely used for polarization maintaining.

What is polarization maintaining fiber and how does it work?

 It is kind of single mode fiber used to balance the direction light, and is available in various capacities. The normal single mode fiber is efficient enough to carry randomly polarized light. Yet, PM fiber is intended to do only one polarization of the input light.

 In the polarization maintaining fiber, the polarization of linearly polarized light waves which is launched into the fiber is maintained at the time of propagation. But there is no cross-coupling of optical power between the polarized modes. The coupler with this feature is extremely important for the some kinds of optical components, for example, external modulators that require a polarized light input.

So it is crucial to buy a coupler that helps you achieve the kind of polarization you need. If you are looking for the polarization fiber that can help you can achieve linear polarization without any no cross-coupling of optical power between the polarized modes, get fused coupler that is  built using  unique fusing technique and polarization maintaining fiber to build the 980/1030/1064nm polarization maintaining fused coupler (PMC). And you can achieve the coupling ration according to your requirement.

Low excess loss, small size and high polarization extinction ratio are what make the fiber a great option for optical sensors and optical gyro. In addition, it has many more features such as:

  • Low Insertion Loss
  • High Extinction Ratio
  • Compact In-Line Package
  • Available for Slow or Fast Axis Operation
  • High Stability and Reliability

The PM Fused Coupler can also be used to split high power linearly polarized light into multiple paths without interfering to the linear state of polarization. The coupler is also used a power control point to monitor the signal power in a PM fiber system. Given the cutting-edge features, fused coupler is widely used for different components requiring light polarization. The fiber can be used for

  • Fiber Optic Instruments
  • Fiber Amplifiers
  • Fiber Sensors
  • Coherent Detecting
  • Research

Check these top dealers to buy the quality Polarization Maintaining Fused Couplers in China for affordable prices.

How does PM Fiber Coupler add value to the multiplexer?

The optical couplers are fused fiber branching devices that split the portion of light allowing optical monitoring. The devices are used extensively in amplifier power control and in transmission equipment for monitoring the performance. The polarization dependent loss coupler is offering low levels of sensitivity to polarization and enables effective management of optical networks. The couplers are available in a wide range of split ratios, lengths and packaging. The Polarization maintaining fused coupler can be bought online for its best usage.

A fused coupler is consisting of two, parallel fibers that can be stretched, twisted, and fused together. The length of the coupling region determines the coupling from one fiber to the other. The Polarization maintaining fused coupler is used to add additional functionality to the network such as network status monitoring. It is the most cost-effective way to minimize the loss and maximize the wavelength isolation. Polarization maintaining fiber coupler is capable of combining two or more inputs into a single output and also divides a single input into two or more outputs.

DK Photonics is the most unique fusing technique that builds the 980/1030/1064nm polarization maintaining fused coupler (PMC). The ratio can be selected according to the requirement and the businesses can benefit a lot buying the fused coupler online.  It features low excess loss, small size and high polarization extinction ratio. The polarization maintaining fused coupler is widely used for optical sensors and amplifiers. A unique fusing technique is used for building the polarization maintaining fused coupler.

How does a fused fiber coupler work?

A fused coupler is consisting of two, parallel optical fibers which are close to each other due to twisting, fusing, and stretching. The length of coupling region determines the coupling ratio from one fiber to the other. Light is launched into the coupling ratio during the manufacturing process and the output power from each output port is carefully monitored. After the achievement of the desired coupling ratio, the fully automated process stops. The process is known as Fused Biconical Taper (FBT) process.

These are the features of Polarization maintaining fused coupler –

  1. It incorporates Low Insertion Loss
  2. It has high extinction ratio
  3. Available in compact In-Line Package
  4. It enables high stability and reliability
  5. It maintains good uniformity with high directivity
  6. Wide variety of wavelengths 780 nm-2005 nm
  7. It is used for fiber optic instruments and fiber sensors
  8. It is also used in research works and enables coherent detection

Polarization maintaining fiber coupler is capable of combining two or more inputs into a single output and also divides a single input into two or more outputs. Make sure that you have the fused coupler for your business or job at the best price and specifications. The coupler are developed using fusing technique and polarization maintaining fiber.