Category: Fiber Transceivers

The requirements for testing fiber optic networks will vary depending on the specific type of network as well as the network designer’s overall test requirements. Regardless of type, there are two basic or generic pieces of Optical Test Equipment that will be used; an Optical Time Domain Reflectomer or OTDR, and a pair of optical test equipment pieces that are referred to as a Power Meter & Light Source. These tests are typically measured in “dB”. The term dB is the expression of attenuation or power loss over an optical fiber as it travels from a termination end to a point along the fiber’s path. Once an optical fiber is connected to a piece of active equipment then all tests are in dBm. The active equipment will be transmitting an actual or real optical power at a specific wavelength and referenced at 1mW.

A PON power meter is essential for field technicians installing or maintaining any type of PON network. PON Power Meters are able to simultaneously test upstream and downstream through optical fibers, at 1490nm, 1550nm, and 1310nm wavelengths, as well as estimate signals of the voice, data, and video streams.

The term PON stands for “passive optical network”. A PON is a fiber optic telecommunications network that delivers broadband to transmit data over fiber optic cables to the customer premises. Its architecture implements a point-to-point or a point-to-multipoint arrangement of nodes in a communications network. A Point-to-Multipoint network uses a single fiber to serve multiple endpoints by using unpowered or passive fiber optic splitters. A splitter is used to divide the fiber bandwidth among multiple access points. Passive optical networks are often referred to as the “last mile” between an internet service provider (ISP) and its customers.

Point-To-Point or P-T-P type optical network

A P-T-P network is a network that has two termination points and nothing in-between. As with all fiber optic networks, when it is being constructed the fibers must be terminated to allow for any tests to be performed. So one end of the network is terminated and an OTDR test is performed on each fiber to ensure that the termination and length of fiber beyond does not have any issues. That test result will be stored for future needs and noted in “dB”. If the network requires splicing then after the fibers are spliced, the OTDR again is used to ensure that the splice and added fiber length again meets requirements. The testing with the OTDR continues and is completed after the end of each fiber is terminated. At this point, another set of tests is required which is commonly referred to as an End-To-End test. This test requires the use of a light source and a power meter and again all test results are stored. The optical power meter will be set to “dB” and referenced to a light source which is typically called “Zeroing”. The units are then moved to opposing ends and the field technicians will send and receive wavelengths specified by the designer. Again this is a measurement that will be used against the designer’s overall Link Loss Budget. The P-T-P network will have its termination ends referred to as “A” and “B” and at least two unique wavelengths will be sent and received over each fiber. This is typically required to ensure that any wavelength used by a transmitter can be used between the two that are specified. The network designer will define these wavelengths as well as provide a label for these ends. The technician that is performing the tests will reference these labels in any reporting back to the designer.

Point-To-Multipoint PON type network

Now when a Point-To-Multipoint network is constructed such as a Passive Optical Network or PON many of the tests and test equipment remain the same but will require a few special features. The OTDR testing during construction remains the same, with tests performed each time a fiber is terminated or spliced. Again, this continues to the far ends of the fibers after they are terminated. Once all fibers are terminated, again they will be tested using a power meter and light source. The need for special equipment is required for the activation phase of a PON network and that’s where the similarity between a P-T-P and a P-T-Multipoint ends.

The PON network activation phase begins by connecting a power meter up to an active piece of equipment called an Optical Line Terminal or OLT and set to the appropriate wavelength and the unit is set to “dBm” and this becomes the referenced power.

NOTE: There are several generations of PON network OLTs which use different wavelengths so the optical power meter must have the capability to be set to those wavelengths. GPON is 1490nm, XGPON is 1577nm and NGPON has multiple wavelengths ranging from 1596nm to 1602nm.

As the links are connected out to the far end, the technician repeats the test and ensures that there are no issues. This testing continues out to the far end, which in a PON network there is a piece of active equipment called an Optical Network Terminal or ONT or at times called an Optical Network Unit or ONU. Regardless, that piece of equipment receives light from the OLT transmitter and communicates back to the OLT with its own transmitter. The ONT cannot communicate back to an OLT without first receiving the OLT’s transmitter’s wavelength. At this time, there is an absolute need to use a specialized optical power meter which can measure the OLT’s power and allow that power to pass through and provide the signal to the ONT/ONU so it can send back a signal.

The PON meter has two test ports; one is named DROP and the other ONT or ONU. The technician connects the drop, which is connected via a fiber all the way back to the OLT into the port named DROP and then connects the ONT/ONU connectorized fiber pigtail into the ONT/ONU port. Now the PON meter is in-line between the OLT and ONT/ONU and allows for the OLT to communicate with the ONT/ONU. The technician again will be observing the incoming OLT power level, as well as the outgoing ONT/ONU power level. If all is well, the drop is connected to the ONT/ONU and service activation tasks can continue.

If the polarization of the input light is not aligned with the stress direction in the fiber, the output light will vary between linear and circular polarization (and generally will be elliptically polarized). And the exact polarization will also be sensitive to variations in temperature and stress in the fiber. The light shall be coupled at the fiber entrance parallel to the slow axis or to the fast axis, then the maintaining of the polarization is therefore possible. It is important to make sure that the polarization of the input light is maintained. PM fiber patch cords maintain the existing polarization of linearly-polarized light that is launched into the fiber with the correct orientation. PM fiber patch cords also feature low insertion loss, high extinction ratio, high return loss, excellent changeability over a wide wavelength range and excellent environmental stability and reliability.

Types of PM Fiber Patch Cords

There are a wide variety of PM fiber patch cords available that support different data rates and suit various connector types. According to different criteria, PM fiber patch cords can be categorized into various types. The following is some detailed information about types of PM fiber patch cords based on 4 different criteria:

Classification by connector type―PM fiber patch cords are capped at both ends with fiber connectors. FC, SC, LC and ST are the commonly used connector types for PM fiber termination. According to the connectors on the both ends, there are many different kinds of PM fiber patch cords, such as LC-FC, SC-FC, or FC-FC PM fiber patch cords.

Classification by fiber type―PM fiber patch cords are built with polarization maintaining fiber. To ensure the polarization of both the input and output light in a PM fiber, several different shapes of rod are used, and the resulting fiber is sold under brand names such as “Panda” and “Bow-tie”. With different PM fiber, there are corresponding PM fiber patch cords, such as Panda PM fiber patch cords and Bow-tie PM fiber patch cords.

Classification by cable type―PM fiber patch cords can also be categorized according to the cable types. There are mainly three kinds of cable types, 250um bare fiber, 900um loose tube jacket and 3mm loose tube jacket. So based on the cable types, there are 3 kinds of PM fiber patch cords.

Classification by fiber length―The standard length is 1 meter. It can vary for special requirements. The length of PM fiber patch cords can be custom made.

Applications of PM Fiber Patch Cords

PM fiber patch cords are often used in polarization sensitive fiber optical systems for transmission of light that requires the PM state to be maintained. PM optical patch cord is a special optical component using the properties of optical fibers specially manufactured so that its transmission parameters can support a particular application. They have a large number of uses, including high-data-rate communications systems, polarization sensitive components, and interferometric sensors. They are also widely used in PM fiber amplifiers, fiber lasers, high speed communication systems, testing equipment and instrumentation applications. Area of use of PM fiber patch cords is very broad and includes equipment such as instrumentation, spectroscopy, aerospace, medical diagnostics and many other industrial applications.

Polarization maintaining (PM) fiber optic patch cord is a kind of special fiber patch cord. It can be used in many areas. Here’s what you need to know about PM fiber patch cords if your designs require them.

What is a PM Fiber Patch Cord?

A PM optical fiber is a single mode optical fiber in which linearly polarized light, if properly launched into the fiber, maintains a linear polarization during propagation, exiting the fiber in a specific linear polarization state. PM fiber patch cord is a fiber optic cable made with PM fiber and terminated on both ends with high-quality ceramic fiber connectors. PM fiber patch cord is a base device of optical passive component.

Characteristics of PM Fiber Patch Cords

If the polarization of the input light is not aligned with the stress direction in the fiber, the output light will vary between linear and circular polarization (and generally will be elliptically polarized). And the exact polarization will also be sensitive to variations in temperature and stress in the fiber. The light shall be coupled at the fiber entrance parallel to the slow axis or to the fast axis, then the maintaining of the polarization is therefore possible. It is important to make sure that the polarization of the input light is maintained. PM fiber patch cords maintain the existing polarization of linearly-polarized light that is launched into the fiber with the correct orientation. PM fiber patch cords also feature low insertion loss, high extinction ratio, high return loss, excellent changeability over a wide wavelength range and excellent environmental stability and reliability.

Types of PM Fiber Patch Cords

There are a wide variety of PM fiber patch cords available that support different data rates and suit various connector types. According to different criteria, PM fiber patch cords can be categorized into various types. The following is some detailed information about types of PM fiber patch cords based on 4 different criteria:

Classification by connector type―PM fiber patch cords are capped at both ends with fiber connectors. FC, SC, LC and ST are the commonly used connector types for PM fiber termination. According to the connectors on the both ends, there are many different kinds of PM fiber patch cords, such as LC-FC, SC-FC, or FC-FC PM fiber patch cords.

Classification by fiber type―PM fiber patch cords are built with polarization maintaining fiber. To ensure the polarization of both the input and output light in a PM fiber, several different shapes of rod are used, and the resulting fiber is sold under brand names such as “Panda” and “Bow-tie”. With different PM fiber, there are corresponding PM fiber patch cords, such as Panda PM fiber patch cords and Bow-tie PM fiber patch cords.

Classification by cable type―PM fiber patch cords can also be categorized according to the cable types. There are mainly three kinds of cable types, 250um bare fiber, 900um loose tube jacket and 3mm loose tube jacket. So based on the cable types, there are 3 kinds of PM fiber patch cords.

Classification by fiber length―The standard length is 1 meter. It can vary for special requirements. The length of PM fiber patch cords can be custom made.

Applications of PM Fiber Patch Cords

PM fiber patch cords are often used in polarization sensitive fiber optical systems for transmission of light that requires the PM state to be maintained. PM optical patch cord is a special optical component using the properties of optical fibers specially manufactured so that its transmission parameters can support a particular application. They have a large number of uses, including high-data-rate communications systems, polarization sensitive components, and interferometric sensors. They are also widely used in PM fiber amplifiers, fiber lasers, high speed communication systems, testing equipment and instrumentation applications. Area of use of PM fiber patch cords is very broad and includes equipment such as instrumentation, spectroscopy, aerospace, medical diagnostics and many other industrial applications.

In fiber optic cable installation, how cables are attached to the system is vital to the success of network. If done properly, optical signals would pass through the link with low attenuation and little return loss. Fiber optic pigtail offers an optimal way to joint optical fiber, which is used in 99% of single-mode applications. This post contains some basic knowledge of fiber optic pigtail, including pigtail connector types, fiber pigtail classifications, and fiber pigtail splicing methods.

Fiber Pigtail Specification

Fiber optic pigtail is a fiber optic cable terminated with a factory-installed connector on one end, leaving the other end terminated. Hence the connector side can be linked to equipment and the other side melted with optical fiber cables. Fiber optic pigtail are utilized to terminate fiber optic cables via fusion or mechanical splicing. High-quality pigtail cables, coupled with correct fusion splicing practices offer the best performance possible for fiber optic cable terminations. Fiber optic pigtails are usually found in fiber optic management equipment like ODF, fiber terminal box and distribution box.

Fiber Pigtail vs Fiber Patch Cord: What Is the Difference?

Fiber optic pigtail has fiber connector installed at only one end, and the other end is left empty. While both ends of a fiber patch cord are terminated with fiber optic connectors. Patch cord fibers are usually jacketed, whereas fiber pigtail cables are usually unjacketed for they are usually spliced and protected in a fiber splice tray. Moreover, patch cord fiber can be cut into two pieces to make two pigtails. Some installers prefer to do this to avoid the problem of testing a pigtail cables in the field—just test the performance of a fiber patch cord, then cutting it into halves as two fiber pigtails.

Fiber Optic Pigtail Types

Fiber optic pigtails are available in various types: Grouped by pigtail connector type, there are LC fiber optic pigtails, SC fiber pigtails and ST fiber pigtails, etc. By fiber type, there are single-mode fiber optic pigtail and multimode fiber optic pigtail. And by fiber count, 6 fibers, 12 fibers optic pigtails can be found in the market.

By Fiber Type

Fiber optic pigtails can be divided into single-mode (colored yellow) and multimode (colored orange) fiber. Multimode fiber optic pigtails use 62.5/125 micron or 50/125 micron bulk multimode fiber cables and terminated them with multimode fiber optic connectors at one end. 10G multimode fiber cables (OM3 or OM4) are also available in fiber optic pigtails. The jacket color of 10G OM3 and OM4 fiber optic pigtail is usually aqua. Single-mode fiber pigtail cables use 9/125 micron single-mode fiber cable and terminated with single-mode fiber connectors at one end.

By Connector Type

According to different types of pigtail cable connector terminated at the end, there are LC fiber pigtail, SC fiber pigtail, ST fiber pigtail, FC fiber pigtail, MT-RJ fiber pigtail, E2000 fiber pigtail and so on. With different structures and appearance, each of them has their own advantages in different applications and systems. Let’s go through some widely used ones.

SC Fiber Optic Pigtail: SC pigtail cable connector is a non-optical disconnect connector with a 2.5mm pre-radiused zirconia or stainless alloy ferrule. SC fiber pigtail is economical for use in applications such as CATV, LAN, WAN, test and measurement.

FC Fiber Optic Pigtail: FC fiber pigtail takes the advantage of the metallic body of FC optical connectors, featuring the screw type structure and high precision ceramic ferrules. FC fiber optic pigtails and its related products are widely applied for the general applications.

ST Fiber Optic Pigtail: ST pigtail connector is the most popular connector for multimode fiber optic LAN applications. It has a long 2.5mm diameter ferrule made of ceramic (zirconia), stainless alloy or plastic. Hence SC fiber pigtails are commonly seen in telecommunications, industry, medical and sensor fields.

Like fiber optic patch cords, fiber optic pigtails can be divided into UPC and APC versions. Most commonly used types are SC/APC pigtail, FC/APC pigtail and MU/UPC pigtail.

By Application Environment

Some pigtail cables are specially installed to withstand the harsh or extreme environments, so here comes armored fiber pigtail and waterproof fiber pigtail.

Armored Pigtail: enclosed with stainless steel tube or other strong steel inside the outer jacket, armored fiber optic pigtails provide extra protection for the fiber inside and added reliability for the network, while reduce the unnecessary damage caused by rodents, construction work, weight of other cables.

Waterproof Pigtail: designed with a stainless steel strengthened waterproof unit and armored outdoor PE (Poly Ethylene) jacket, waterproof fiber pigtail is a great fit in harsh environments, like communication towers, CATV and military. Waterproof pigtail cable boosts good toughness, tensile and reliable performance, facilitating the use in outdoor connections.

By Fiber Count

Fiber optic pigtails could have 1, 2, 4, 6, 8, 12, 24 and 48 strand fiber counts. Simplex fiber optic pigtail has one fiber and a connector on one end. Duplex fiber optic pigtail has two fibers and two connectors on one end. Each fiber is marked “A” or “B” or different colored connector boots are used to mark polarity. Similarly, 4, 6, 8, 12, 24, 48 and more than 48 fibers fiber optic pigtails have their corresponding feature.

Fiber Optic Pigtail Splicing: Easy and Fast Fiber Termination

The quality of fiber pigtail is typically high because the connectorized end is attached in the factory, making it more accurately than a field-terminated cables. It can be attached to optical fibers by fusion or mechanical splicing. Given the access to a fusion splicer, you can splice the pigtail right onto the cable in a minute or less, which greatly speeds the splicing and saves significant time and cost spent on field termination. While for mechanical fiber optic pigtail splicing, it precisely holds a fiber optic pigtail and fiber patch cord together, the joint could be temporary or permanent, enabling light to pass from one fiber to the other. Always ordering fiber pigtail assembly a few feet more than you’ll need. The extra slack allows for splicing errors to be corrected. Besides, selecting fiber pigtail assembly with reliable quality would made the splicing process way easier.

Network cables are maximum absolutely wanted in conversation. They are used to hold indicators from one point to some other. However, many humans have show extra than just any everyday pleasure with the use fiber optic community cable. However, you have to know which you are about to get excited too once you may understand that these fiber optics to your network cable are not simply your common cable that deliver the sign to facilitate verbal exchange.

This fiber optics can do greater in your network cabling efforts. They are so not like your common network cable that contains confined velocity and also have obvious flaws that make more room for development. You should realize more of the things that you will reap from these cables. For one, fiber optics already use light waves as the alerts on your community cable. Thus, you could do away with faltering signal. You can handiest assume outstanding sign with speedy velocity, as rapid as light. There are many blessings in using fiber optic community cable.

Clear sign with outside interference

Fiber Optic Curing Ovens can bring more than one alerts in a single channel, in contrast to regular cable that cannot appear to be confused with extra alerts due to the lack of bandwidth. Moreover, fiber optics can nonetheless defend its signals from any outside interference from different indicators. Optical cable can come up with clear excellent sign because of its balance in opposition to different indicators.

Tight protection in carrying message packets

This is feasible due to the fact breaking light alerts in optical cables is simply difficult. Thus, the message carried thru fiber optics could not be hacked. Ordinary co-axial cables can effortlessly be intercepted with the message in the indicators at once received. If you want a secure communication over the Internet and a stable reference to your TV network, this new fiber optic network cabling can without a doubt help you.

Speedy connection because of light-based totally signals

In fiber optics, the cables would deliver mild rays as alerts. Thus, you can assume that your message will tour as speedy as light. Thus, messages can help maintain up with actual time updates and exchanges. This sort of cable might assist you hook up with the Internet and cable with top speed. When you chat with your different pals over the Internet, you could get hold of their messages fast too.

Stable message regardless of climate

The sign of your cable will not be determined by using the climate situation in your place if you’ll transfer to using fiber optics. By the usage of mild indicators, fiber optics network cables can protect the speed and overall performance of the sign from any modifications in the temperature and different climate changes. Thus, you’ll still get your rapid Internet connection regardless of what’s happening exterior.

Fiber patch cables are common assemblies seen in optical communications to link devices and network components. To ensure normal optical transmission and fiber durability, it is necessary to get familiar with the user instructions and precautions. This post will introduce the precaution for taking care of fiber patch cables from the perspectives of connecting, disconnecting, and routine maintaining, which is recommended for you to prevent a series of possible harmful consequences.

Connecting and Disconnecting Fiber Patch Cables

Fiber patch cables can be used with many network devices, such as optical transceiver modules, fiber adapter panels, fiber cassettes, media converters, and other products having fiber optic interfaces. The following part will introduce the general steps for connecting and disconnecting fiber patch cords, taking connecting a fiber patch cable to a transceiver installed in a network switch as an example.

Connecting Fiber Patch Cables

Remove the rubber safety caps covered on the fiber optic connectors at both ends of fiber patch cables and remember to keep these caps well.

Remove the cap from the optical transceiver.

Insert the cable connector into the optical transceiver.

Fix and fasten the fiber patch cables by placing fixing elements on a loop to help cables maintain their shape.

Disconnecting Fiber Patch Cables

Disable the interface in which the optical transceiver is installed by running a command.

Carefully unplug the cable connector from the transceiver.

Cover the transceiver with a rubber safety cap.

Cover the cable connector with a rubber safety cap.

There are some points that should be noted during the connecting and disconnecting process:

The installation personnel needs to be skilled enough with an understanding of the network layout so as to ensure the quality and safety of the installation.

Always wear safety glasses and protective glasses to avoid electric shock or touching fiber shards. Anti static wrist strap band is necessary to reduce static electricity when operating with active devices.

Pay attention to the bending radius of the fiber patch cords. Excessive pulling or squeezing will possibly cause damage to fiber jumpers.

Do not let the jumpers hang free from optical transceivers or run free on the floor randomly. It is very likely to stress the cables at the fastening point or break the cables once pulling the cables accidentally

Never look directly into the end of fiber cables when there is a laser coupled to it for the safety of your eyes.

Avoid frequently inserting or removing fiber patch cables from devices or the fiber end face will produce wear.

Thoroughly clean the working area after the completion of installation.

Maintaining Fiber Patch Cables

The daily maintenance for fiber patch cables matters a lot in the fiber optic system. There are two main aspects to which you should pay attention during routine maintenance.

Keep Fiber Patch Cables Clean

It is often heard that special attention should be given to the fiber optic patch cable cleaning, but are you clear why it is so important? In brief, for reliable and robust fiber optic networks. According to an industry survey by a major telecom company, contamination is the number-one reason for troubleshooting optical networks. Fibers are so fragile that once they are covered by dust or other contaminations, the optical signal can be degraded. What’s more, the metallic particles worn by the bodies and fiber housings of the fiber optic connectors will block a fiber, which will cause signal loss, thus eventually reducing the network performance and causing a great loss for businesses that rely on fiber-optic networks.

Generally, fiber optic cleaning refers to cleaning fiber connectors. How to ensure you clean fiber connectors using correct ways? There are two main cleaning methods: dry cleaning and wet cleaning, each performing different functions. Reel-type fiber cleaners, pen cleaners, fiber cleaning wipes, and foam swabs are the common fiber connector cleaning solutions. More information about these solutions and cleaning steps is available in How Much Do You Know About Fiber Connector Cleaning?

Store Fiber Patch Cables Properly

No matter a fiber cable is in use or out of use, there is one significant point to be considered: Do not bend or stretch your fiber cable too much. It is often the case when working with fiber optic cables, people stretch or bend them. For this reason, the worst case is the fiber may get damaged. Some breakage caused by bending can be visible, but some loss may not, such as microscopic fiber deformations caused by very low temperature, displacement of a few millimeters caused by buffer or jacket imperfections, poor installation practice or other factors. Since such loss can not be seen by the human eyes directly, it will be overlooked and things can get even worse over time. In case of a huge loss when the fiber patch cords must be replaced, the following essential elements need attention:

Design your fiber cable pathway using proper tools or components to protect fibers, such as horizontal cable managers.

Do not bend fiber patch cables beyond their minimum bend radius, especially in those tight spaces of high-density fiber patching areas.

Make sure not to hit the fiber connector against anything! On the one hand, those ends may get abraded or broken. On the other side, broken glass at the fiber end can cut someone’s skin. It is suggested to use protective caps when storing or pulling fibers.

OTDR and optical fiber microscopes are recommended if you need equipment for measuring and identifying any faults such as breaks within the fiber cable or overall attenuation.