Category Archives: Bulk Fiber Cables

What Is Polarization Maintaining Fiber Patch Cable?

The inherent advantages of light are doomed to play an important role in human history. With the booming of human technology, the development of optical fiber communication has made new progress. In the field of optical fiber communication, the most familiar thing for us should be fiber optic cable and patch cable. However, in addition to conventional fiber patch cable, there are some special kinds of fiber patch cable that we have never known. Today, let’s talk about a kind of special optical fiber patch cable: polarization maintaining fiber patch cable (PM Fiber).

Polarization Maintaining Fiber Patch Cable

Polarization Maintaining Fiber Patch Cable

What Are Polarization and Polarization Maintaining Fiber Cable?

If we want to understand PM fiber, we must first understand what polarized light is. Light is a kind of electromagnetic wave. It consists of an oscillating electrical field and a magnetic field. Its properties can be described by studying its electrical field, although we can also describe light and its effects in terms of magnetic field. Light waves can vibrate in many directions. When light vibrate in one direction, such as up and down in a single plane, they are called polarized light. When light vibrate in multiple directions, such as up/down and left/right, on more than one plane, they are called unpolarized light.

What Is Polarization Maintaining Fiber Patch Cable?

The polarization of light propagating in the fiber varies gradually in an uncontrolled (wavelength-dependent) manner, depending on its temperature and any bending of the fiber. Special optical fiber is needed to achieve optical performance, which is affected by the polarization of light passing through the optical fiber. Many systems such as fiber interferometers and sensors, fiber lasers and electro-optic modulators also suffer from polarization-dependent losses (PDL) that may affect system performance. In order to solve this problem, polarization maintaining fiber patch cable was developed. It is a special type of single mode optical fiber. Ordinary single mode optical fiber can carry random polarized light. However, the polarization maintaining fiber patch cable is designed to propagate only one polarization of the input light.

Types of Polarization Maintaining Fiber Patch Cable?

There are many kinds of polarization maintaining fiber patch cable, which support different data rates and are suitable for various connector types. According to different classification standards, polarization maintaining fiber patch cable can be classified into various types.

  • Classified according to connector type – The ends of polarization maintaining fiber patch cable are sealed by optical fiber connectors. The connectors commonly used at both ends of PM fiber are FC, SC, LC and ST. Therefore, according to the connectors at both ends, there are many different types of PM fiber, such as LC-FC, SC-FC or FC-FC polarization maintaining fiber patch cables.
  • Classified according to fiber type – PM fiber is made up of polarization maintaining fiber. To ensure the polarization of the input and output light in PM fiber, we use several different shapes of rods, and the resulting fibers are sold under trademarks such as “Panda” and “Bow-tie”.

Applications of Polarization Maintaining Fiber Patch Cable

Polarization maintaining fiber patch cable is also commonly used in telecommunications for the connection between source lasers and modulators. Because modulators require polarized light as input. Furthermore, it is used for special applications, such as quantum key distribution, interferometry and optical fiber sensing. But, they are rarely used for long haul transmission because Polarization Maintaining Fiber Patch Cable are more expensive and more attenuated than single-mode fibers.


In today’s optical fiber communication systems and applications, it’s necessary to understand polarization. And, it’s important to understand how to characterize and process polarization effects in order to maximize the performance of systems involving polarization sensitive devices. Polarization maintaining fiber patch cable is based on high-precision butt joint technology to maintain polarization. You can contact FS.COM, if you want to know more information.

Flat vs Round Ethernet Cables: How They Differ from Each Other?

As everyone knows, if you want to set up a home or office network, some particular devices will be needed, such as routers, switches, hub, connectors, modems, Ethernet cable, etc. Among them, we are very familiar with Ethernet cable. As many people know, there are some common types of Ethernet cables, such as Cat5 cable, Cat5e cable, Cat6 cable and Cat7 cable. But many people don’t know that there are actually two different types of Ethernet cables accessible on the market: flat Ethernet cables and round Ethernet cables. Then what’s their differences? Should we use flat Ethernet cable or round Ethernet cable? Here will cover these topics on flat vs round Ethernet cables: how they differ from each other?

Flat vs Round Ethernet Cables: What Are They?

To be honest, the Ethernet cables are always mentioned when people set up a wired internet network. However, just as mentioned above, many people do not know that there is another way of classifying Ethernet cables. That is, it can be classified into flat Ethernet cables and round Ethernet cables. So what exactly is flat Ethernet cables and what is round Ethernet cables?

What Is Flat Ethernet Cables?

After World War II, the flat Ethernet cable was made and became popular. Since then, they’ve been used in many fields, such as military, aerospace, robotics, etc. The flat Ethernet cables have many advantages, just like they are flexible in usage, efficient in packaging, and resistant to electronic noise. Besides, with their stability during working, flat Ethernet cables can be an ideal choice for current wired Internet networks.

flat vs round Ethernet cables: Flat Ethernet Cable

Figure 1: Flat Ethernet Cable

What Is Round Ethernet Cables?

As a form of insulated wire, the round Ethernet cable contains some layers of filler material, all these make the shape of the Ethernet cable round. The round Ethernet cables also have many advantages, such as it is capable of minimizing the cable heating that caused by friction and preventing it from external environment.

flat vs round Ethernet cables: Round Ethernet Cable

Figure 2: Round Ethernet Cable

Flat vs Round Ethernet Cables: How They Differ from Each Other?

In some specific industries, the two types of Ethernet cables are used. While, both have their own edges over each other. Now, let’s look at the difference between flat Ethernet cable and round Ethernet cable.

  • 1. The round Ethernet cable has a bunch of insulated wires surrounded by several layers of other filler materials. These layers are used to maintain the circular profile and minimize friction heating when the cable moves. The wires and fillers are surrounded by an outer sheath that holds them all together and provides a degree of protection against external components. While, the flat Ethernet cable doesn’t have this edge.
  • 2. However, also because the round Ethernet cable contains these multiple layers conductors, insulators and fillers, the heat dissipation of the conductors in a circular cable may be problematic. Despite the measures taken to reduce it, friction heat still occurs within the cable during repeated motion cycles. Similarly, this problem won’t occur in flat Ethernet cables, either.
  • 3. Within a flat Ethernet cable, each conductor is kept parallel to the adjacent conductor, forming a flat profile. So conductors in flat cables do not move within the package, and their electrical properties can remain unchanged. Furthermore, all the conductors in the flat cables have the same physical and electrical length. Therefore, the signal skewing and differential time delays between the signals in the cable are at the minimum.
  • 4. Lastly, because the flat Ethernet cable doesn’t contains the multiple layers conductors, insulators or fillers, it has the edge of volume and weight reduction. But, this also makes flat Ethernet cable needs more maintenance. On the contrary, The round Ethernet cable are more durable.

Flat vs Round Ethernet Cables:Which Will You Choose?

There is no doubt that both the flat Ethernet cable and the round Ethernet cable have their own advantages. The modern Ethernet cables has been designed to overcome many difficulties. You can choose the right one that meet your requirement. You can find good Ethernet cables that meet your requirements at FS.COM. Please contact us if you have questions or needs about Ethernet cables.