Category: PM Components

How Does Polarization Maintaining Fiber Work?

Polarization-maintaining fiber is a fundamental component in fiber optics. It is often abbreviated as PMF or PM fiber. In simple terms, it is a single-mode optical fiber that allows the linearly polarized light to preserve its polarization state while propagating across it, given that the linearly polarized light is properly launched into the fiber. Consequently, there is negligent or no cross-coupling of optical power between two polarization modes. This type of optical fiber is essential for applications where polarization preservation is important.

Now that you know what polarization-maintaining optical fiber is, let’s dive into how it works.

How Polarization-Maintaining Optical Fiber Works

To make polarization-maintaining optical fiber work, a systematic linear birefringence is intentionally introduced. It allows two well-defined polarization modes to travel across the fiber with very different phase velocities.

PM fiber is often characterized by its beat length for a particular wavelength, represented as Lb. The beat length is the distance over which the wave in one mode experiences an additional delay of one wavelength when compared to the other polarization mode. Hence, PM optical fiber of the length Lb /2 is considered equivalent to the half-wave plate.

Now consider the fact that random coupling might occur between two polarization states over a significant length of PM fiber. In such a scenario, at the very initial point 0 along with the fiber, the wave in polarization mode 1 induces amplitude into mode 2 at some phase.

However, at point ½ Lb along with the fiber, the same coupling coefficient between the two polarization modes induces an amplitude into mode 2 which now becomes 180 degrees out of phase with the wave coupled at point 0 and hence results in cancellation.

Now, at point Lb along with the fiber, the coupling is again in its original phase but then, at 3/2 Lb it will get again out of phase. This phenomenon will keep occurring so on.

Hence, the chances of coherent addition of wave amplitudes through cross-coupling over distances that are larger than Lb get eliminated. Most of the power of the wave remains in its original polarization mode and therefore, exits the fiber in the same mode as well.

Thus, optical fiber connectors that are used for PM fibers are specifically used in a way so that the two polarization modes remain aligned with each other and exit in a specific orientation.

Remember that polarization-maintaining fiber doesn’t function like a polarizer as it doesn’t polarize the light. It simply maintains the linear polarization of the launched linearly polarized light that aligns with one of the fiber’s polarization modes. If a linearly polarized light is launched into the fiber at a different angle, it will excite both polarization modes and will allow the light wave to propagate at slightly different phase velocities.

DK Photonics is a top-notch China-based manufacturer of polarization-maintaining fiber in a variety of specifications. If you don’t see PM fiber with the specifications that you need, don’t worry. We also offer customized orders. So, please feel free to contact us to discuss your custom specifications for PM fibers.   

What are the dynamic characteristics of Polarization Maintaining Fused Coupler?

Polarization maintaining fused coupler is covering a wide range of optical devices that may have been used or not, includes optical splitters, optical combiners, and couplers. The couplers are operating in different applications that require other than specific connections. The fused coupler is used to split optical signals between two fibers into one and they are constructed by fusing & tapering the fibers together. This method is used for creating a simple and rugged method of splitting. Polarization maintaining fused coupler is built using unique fusing technique and polarization maintains fiber.

What is the main use of PM fused couplers?

The PM fused coupler is the type of component that is allowing the redistribution of optical signals. The device is able to distribute the other optical signals from one fiber among two or more fibers. The coupler is having the ability to combine the optical signals from two or more fibers into a single fiber.  The input signal is not directly transmitted from one fiber to another, but divided among the output ports.

The operating wavelength of fused PM Splitter is up to ±20 nm for 1550 nm region devices. If you are looking for a fused coupler for operations within the standard bandwidth or splitter, it is best to order a standard center wavelength. There are companies manufacturing the polarization maintaining fused coupler. The manufactures uses unique fusing techniques and PM fiber to build couplers. They have the features of excess loss, small size and high polarization extinction ratio.

The PM fused coupler is split into high power linearly polarized light into multiple paths without perturbing the line. It is also used as the power tap to monitor signal power in a PM fiber system without disturbing the linear SOP of light propagating in the PM fiber.

Listed below are the features of PM fused coupler –

  • Available for slow or fast axis operation
  • Compact in-line package
  • High extinction ratio
  • Low insertion loss
  • High stability and reliability

The fused coupler is used in applications like fiber optic instruments, fiber amplifiers, fiber sensors, coherent detecting, and research. Optical couplers are important devices in optical communication and there are various types of optical couplers with different transmission characteristics. Fused PM splitters have a wide variety of options with the standard configuration of 1×2, 2×2, 1×3 (monolithic) and 1×4 (compact cascaded). The couplers are configured and built in-line with the industry requirement.

Significance of Using the Right Polarization Maintaining Fiber

Fused Coupler is a type of optical fiber that is used to split high power single line polarized light into multiple directions without disturbing the line at the state of polarization. This fiber is also used as a power tap to monitor signal power in a PM fiber system. A fused coupler is widely used in PM fiber interferometers, power sharing in polarization sensitive systems, and signal monitoring in PM fiber systems.

Couplers are generally divided into two categories- passive couplers and active couplers. The passive couplers are able to redistribute the optical signal without making optical to electrical conversion while active couplers electric devices used to split or combine signals electrically using a device called fiber optic detector and sources for input and output.

Based on applications, the couple has different types. So to make sure you choose the right coupler, it is crucial to know about them.  Here, we will shed light on some of the most important ones that are widely used today.

T coupler

Also, called Y coupler, it is a three port device and mainly used for power monitoring. It is also used for splitting the power input into two equal outputs.

Tree coupler

Its main work is to split the single input into multiple outputs. It is used as a combiner to combine multiple output signals.

Star coupler

It is pretty well different from the first two. Unlike them, this coupler has multiple inputs and multiple outputs. The fibers radiate from the central point likes a star. And this is why it is called star coupler.

Wavelength selection coupler

Also known as WDM (wavelength division multiplexer, wavelength selection coupler splits the signal based, not on power.

Having a look at the types of couplers and their applications, it is quite clear that each of them has a different application. And so they perform well in a particular situation and meet a particular need. If you are looking a coupler, it is very important to choose the one that best meets your needs.

 And the best way to know which one will work best for you are looking at your needs. Yes, first of all, you should figure out your requirements. This will make it easy for you to come out with the right option without wasting your time.

Features of top couplers for polarization-maintaining

 In addition to the types of a coupler, the features of coupler also play a vital role in selecting. Here are some of the top features that you must consider when looking for the one for you. A quality fused coupler has:

Low insertion loss
• High extinction ratio
• Compact In-Line Package
• Available for Slow or Fast Axis Operation
• High Stability and Reliability

Whether you are looking for couplers for the use of Fiber Optic Instruments, Fiber Amplifiers, Fiber Sensors, or Coherent Detecting devices, choose the one, keeping in mind the above features. Also, make sure to buy only from top suppliers of Polarization Maintaining Fused Couplers in China.

Enhance the quality of your fiber optics with polarization beam combiner

A whole new level of communication was achieved with fiber optic cables for communication coming into use in our daily routine. The implementation is done at full throttle of a single fiber optic to send out and bring in a great number of signals, immensely cut down the costs that are invited by the telecom companies, and hence it has achieved enormous recognition.

Each and every day various business houses are moving forward in seeking various substitutes that can help in augmentation of their individual communication experiences. It is a new level of marvel in technology that has highly advanced the quality of fiber optics with the due help of Polarization Beam Combiner. To clearly come to an understanding of this technology, it would take quite a while, but to comprehend the upper layer of it get hold of the basics is not a task. These are majorly divided into two subcategories that are, the incoherent polarization combining and coherent polarization combining.

Polarization Beam Combiner: This device is a robust one that holds the capacity to strongly bring together two phases’ modulated input fibers into a single output fiber or segregating the polarization components of an input fiber connecting two output signals.

  • The handling becomes far easier with these tough devices that are specifically designed with bulkhead connectors.
  • It also holds the capacity to lessen the damage to the environment, given the length of the fiber is really small.
  • The performance they give against the loss of insertion, extinction ratio, and back reflection is amazing.
  • The bandwidth of the operation is really wide on this one and holds the capacity to easily handle signals of a variety of wavelengths.
  • The capacity of handling the power in this device is very high.
  • They very easily have the operational value of working between the ranges of -5 to +70°C.

The application of Polarization Beam: The polarization beam application is wide; it is used in a variety of devices like amplifiers, fiber laser systems, fiber sensor systems, research development, polarization division multiplexer and demultiplexer etc. and the performance it provides is exceptionally well. It has far above the ground permanence and dependability and more to the point features mentioned above. The polarizing beam combiners characteristically have 0° or 45° angle of incidence and a 90° division connecting the beams; this, by and large, is dependent on the arrangement.

A polarization beam combiner is more often than not used in photonics instrumentation, optics, and semiconductors to broadcast p-polarized light and at the same time as reflecting-polarized light. These grasp a world of value when it boils to optics, telecommunication, and fiber applications, and while in the process also makes the functioning effectual as well as unproblematic.

PM Fiber Coupler will add value to the multiplexers and de-multiplexers

A fiber coupler or fiber optic coupler is a device used in optical fiber system with one or multiple input fibers and one or several output fibers. The power distribution is dependent on the wavelength and polarization as the light is entering an input fiber. These couplers can be fabricated in different ways like thermally fusing fibers. There are also couplers that can combine two inputs at different wavelengths into one output without any loss. It is mainly used in wavelength-division multiplexing (WDM) telecom systems to combine the several input channels.

Polarization Maintaining Fiber Coupler
Polarization Maintaining Fiber Coupler

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. The fused coupler is developed using fusing technique and polarization maintaining fiber. Certain applications for PM couplers include optical sensors, optical amplifiers, and fiber gyroscopes. They are more useful in optical communication & transmission and is available in different configuration of 1×2, 2×2, 1×3 (monolithic) and 1×4 (compact cascaded).

Features and characteristics of PM fiber 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

They provide an improved PER (≥20 dB including connectors) and a wide -40 °C to 85 °C operating range. The couplers undergo extensive testing and verification of the PER and they are available with 2.0 mm narrow key FC/PC and FC/PC connectors. The IL will be 0.3dB higher and RL will be 5 dB for devices with connectors. The extinction ratio is also specified in the same way and they are aligned to the slow axis of the fiber. They are available in compact packaging options and it is advisable to contact the companies who specialize in the manufacturing of PM Fiber Coupler.

10-Year Forecast – Fiber Optic Sensors

According to ElectroniCast, the combined use of Distributed and Point fiber optics sensors are forecast to reach $5.98 Billion in 2026…

 ElectroniCast Consultants, a leading market/technology forecast consultancy, today announced the release of their market forecast and analysis of the global consumption of Fiber Optic Sensors.

According to the study, the combined use of Distributed and Point (local) fiber optics sensors reached $3.38 Billion last year (2016), and the worldwide value is forecast to reach $5.98 Billion in 10-years (2026). Market forecast data in this study report refers to consumption (use) for a particular calendar year; therefore, this data is not cumulative data.

Both the American region and the EMEA region held similar market share in the overall (distributed- and point-types) fiber optic sensor value last year. The Europe, Middle East, Africa region (EMEA) held a very slight lead in relative market (value) share last year; however, the Asia Pacific region (APAC) is projected to take-over the leadership position during the forecast period.

The EMEA region is forecast to have a strong role in the use of distributed fiber optic systems, driven by the region’s use of systems in aviation, as well as in the

Petrochemical, Natural Resources, Energy/Utility application categories.

In terms of fiber optic point sensors, the American region is forecast to maintain the market share lead throughout the 1st-half of the forecast period (2016-2021), mostly led by the use of Fiber Optic Gyros (FOGs) in the Military/Aerospace application category. The consumption values are based on the end-user application and the end-user region.

FOGs held a 65 percent market share of the worldwide Point fiber optic sensor consumption value in 2016. “All regions, thanks mainly to increases in the use in aviation and military critical mission applications (Unmanned Aerial Vehicle/UAV and missile guidance, navigation, north finding/tracking, robotics, aviation and aeronautics and other) are forecast to show impressive increase consumption quantity (volumes) and values for the FOG systems,” said Stephen Montgomery, Director of the Fiber Optics Components group at ElectroniCast Consultants.

The market forecast of the Distributed Sensors is segmented by the following applications:

  • Manufacturing Process/Factory
  • Civil Engineering/Construction (buildings, bridges, tunnels, etc)
  • Military/Aerospace/Security
  • Petrochemical/Energy/Utilities/Natural Resources
  • Biomedical/Science

The Fiber Optic Point Sensor Forecast further segmented by the following sensing/measuring quantity (measurand) types:

  • Mechanical Strain
  • Temperature
  • Pressure
  • Chemical, Gas, Liquid
  • Vibration, Acoustic, Seismic
  • Displacement, Acceleration, Proximity
  • Electric, Current and Magnetic Field – Fiber Optic Sensors
  • Rotation (such as Fiber Optic Gyroscopes: FOGs)

“ElectroniCast counts each Point fiber optic sensor as one unit; however, the volume/quantity (number of units) of Distributed fiber optic sensors is based on a complete optical fiber line/link, which we classify as a system. Since a distributed optical fiber line (system) may have 100s of sensing elements in a continuous-line, it is important to note that we count all of those sensing elements in a distributed system as one (system) unit – only. Distributed fiber optic sensor systems involve the optic fiber with the sensors embedded with the fiber; also included is the optoelectronic transmitter/receiver, connectors, optical fiber, cable (fiber jacket) the sensor elements, and other related components,” Montgomery added.

According to ElectroniCast, the combined use of Distributed and Point fiber optics sensors reached $3.38 Billion in 2016…

 

Continuous Distributed and Point Fiber Optic Sensor

Global Consumption ($3.38 Billion in 2016)

Source: ElectroniCast Consultants


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DK Photonics – www.dkphotonics.com  specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as 1064nm High Power Isolator,1064nm Components, PM Components, (2+1)x1 Pump Combiner,Pump Laser Protector,Mini-size CWDM,100GHz DWDM,Optical Circulator,PM Circulator,PM Isolator,Fused Coupler,Mini Size Fused WDM.