Category: Fiber Tester & Tools

Fiber optic testers, fiber optic tools, fiber splicing, fiber polishing, copper testers and tools.

Proper Care of Polishing Fixtures for Optical Fiber Polishing Machines

In fiber optic cable assembly, the polishing process is perhaps the most critical step to assure high-quality assemblies that meet specifications. That’s why it’s important to select the right optical fiber polishing machine – and polishing fixtures – that meet your needs. Depending on your cable assembly house product offerings, it’s likely that you have several polishing fixtures to produce different connector styles.

The quality of the polishing fixtures (also called polishing plates or jigs) is extremely important to your company. Considering the high cost of production equipment and components, your company will want to maintain these tools to produce a high volume of products with minimal quality issues over the long run.

Proper maintenance of polishing fixtures is absolutely essential

Polishing fixtures for optical fiber polishing machines are built with high-precision machining equipment. Fixtures made of steel and aluminum can flex and warp over time, which will negatively impact your polishing process and product quality. On the other hand, polishing fixtures made of hardened stainless steel avoid this wear effect. However, hardened stainless steel contains more iron in the alloy, so this does increase the risk of rusting. This is a key reason why proper maintenance is so critical.

In addition, the most common fiber optic connectors (SC, LC, and E2000) are locked onto the polishing fixture with a plastic latch or clamp, which can wear over time if not properly cleaned. Poor cleaning techniques can also prevent proper locking. This can significantly impact the polishing machine’s functionality and, therefore, product quality.

Polishing fixtures are expensive – this is a bottom-line reason why proper maintenance is so important. With daily maintenance, you can use your polishing fixtures for a long time with no variation in the quality level of your fiber optic cable assemblies.

Follow these 8 steps to clean and maintain your polishing fixtures

Whether your company is just starting to manufacture fiber optic cable assemblies – or you have years of experience – we recommend you rigorously follow these guidelines to properly clean and maintain your polishing fixtures.

It’s better to clean every day for 5 minutes rather than clean once a week for 30 minutes. In fact, we recommend you integrate a cleaning procedure throughout the daily polishing process. Cleaning the fixtures should be a regular task – and a priority – in your polishing process.

Use distilled water, because it doesn’t contain abrasive minerals. Do not use tap water – regular drinking water is different all over the world. Your company’s tap water may contain iron minerals that tend to adhere to the polishing fixture. Also, do not use alcohol. At Fiber Optic Center, we recommend the Air Cleanse Cleaning Wand. This hand-held cleaning wand has an integrated pressurized fluid and filter system for a debris-free cleaning operation. You can use the wand to clean any brand of polishing machine and fixture. Click to read the datasheet for the Air Cleanse Cleaning Wand from Domaille Engineering.

The ferrule holes (and for MT style fixtures the ferrule slots, surrounding surfaces, and top clamps) can be cleaned using dental brushes and particle‐free, distilled or deionized water. Again, do not use alcohol. We recommend using a 1.25mm nylon brush (purple-handled brush) for fixtures with 1.25mm diameter ferrule holes. Use a 2.5mm nylon brush (blue-handled brush) for fixtures with 2.5mm diameter ferrule holes. Either one will work fine for MT style fixtures.

Clean the fixture while it’s still wet from the polishing process. This makes it easy to remove the polishing debris.

To clean areas where a brush can’t reach, use an ultrasonic bath. When using an ultrasonic bath, you must change the deionized water every day. Otherwise, debris could contaminate the polishing fixture. (Again, here is the link for the Air Cleanse Cleaning Wand datasheet.)

If you have a fixture with a cam-lock interface, pay special attention to the spring slits. These are very narrow and debris can easily build up, causing the metal to flex less and interfere with the spring functionality.

After cleaning the polishing fixture, it’s important to dry it thoroughly to avoid rusting. This is especially true for polishing fixtures made of hardened stainless steel.

Over time, your polishing results may change, and the reason could be directly related to natural wear of key interfaces of the polishing machine and fixture. The EZ-Check Precision Wear Gage Kit provides precise measurements for the polishing machine mandrel, fixture mounting hole, and ferrule holes. We recommend incorporating this wear gage kit into your process control system. Call Fiber Optic Center to determine whether this tool works with your polishing machine and fixture.

Fiber Optic PC Connectors: Single-channel vs. Multi-channel

Over the past 30 years, fiber optic technology has spanned its commitment constantly with, even more, endeavors nowadays to meet the ever-increasing networking bandwidth for high-quality Internet applications. In these applications, fiber optic connectors, serving as mousetraps, are used to couple the source, receiver and other components to the fiber optic cable. Fiber optic connectors generally use either physical contact (PC) or expanded beam technology. This article mainly discusses PC connectors from single-channel and multi-channel aspects.

It’s necessary to figure out what PC connections are first.

What Are PC Connection?

A PC connection is accomplished by terminating the optical fiber into a precise ceramic ferrule. The tip of the ceramic ferrule is polished in a precise manner to ensure that light enters and exits at a known trajectory with little scattering or optical loss. In achieving PC connection, there are two requirements for a cleaved fiber end face for PC connection. One is that the fiber end face inclination is less than 0.6°, and the other is that there is no mist on the end face.

PC Connector Types

There are countless single-channel and multi-channel fiber optic PC connector types available for telecommunication and data communication industries.

Single-channel Connectors

PC connectors are characteristic of directly mating and polishing fibers by utilizing tight tolerance ferrules and alignment sleeves and/or mating pins. This ceramic-ferruled technology permits reliable optical performance, with several designs becoming widely used as industry standards. Typically, these connectors are single fiber solutions with plastic shells. FC and ST connectors are becoming less popular but are still used in instrumentation. LC and SC connectors are commonly used in the telecommunication industry.

As a push-pull connector, LC connector, licensed by Lucent Technologies, provides a pull-proof design and small size perfect for high-density applications. It’s available in simplex or duplex versions, widely used in 10Gigabit, 40Gigabit, and 100Gigabit applications. Like Cisco QSFP-40GE-LR4 transceiver, QSFP-40GE-LR4 listed on Fiber-mart.com establishes 40Gigabit Ethernet (GbE) links with this duplex LC connector for 10km maximum link length over single-mode fiber (SMF).

SC connector, developed by Nippon Telegraph and Telephone (NTT), is recommended in the TIA/EIA-568-A Standard for structured cabling. It’s also available in simplex or duplex versions, typically used in Analog CATV (Cable Television) and other telecoms applications including point to point and passive optical networking.

Multi-channel Connectors

Multi-channel connectors house multiple fiber optic termini in a precision insertion. The termini can be configured as a pin/socket combination or genderless. MTP/MPO connectors belong to PC multi-channel connector.

The US CONEC MTP is an MPO compatible connector that exhibits quick and reliable connections for up to 12 fibers in a very small form factor. Just like LC connector, 40G links are likely to deploy this kind of MPO-12 connector for high performance. Take Cisco QSFP-40G-CSR4 for example, this QSFP-40G-CSR4 transceiver sets up 40G links in 850nm multi-mode fiber (MMF), with MPO-12 as its connector.

Optical Performance

Both single-channel and multi-channel PC connectors have optical performance characterized by return loss. The return loss of the connector is a measurement of how much light is reflected back at the connector interface. It’s affected by alignment, contamination, and polishing. For example, if the mating faces of the two fibers are not parallel, some energy reflects back to the source. Additionally, contamination at the mating interface causes reflection and scattering of light. What’s more, a poor polish may create an end-gap separation or an end angle.

Featuring by the tightest tolerance ceramic ferrules and alignment sleeves, coupled with the highest quality termination and polishing procedures, PC connections are able to deliver unrivaled optical performance.

Conclusion

Fiber optic connectors make quick fiber connection and efficient light transmission possible, gaining more and more popularity among their users. Fiber-mart.com offers hundreds of fiber optic connectors, such as FC, D4, DIN, MU, the MTP/MPO ST, SC and LC, as well as their related optic modules (eg. QSFP-40GE-LR4 and QSFP-40G-CSR4 mentioned above). You can visit Fiber-mart.com for more information about fiber optic connectors.

What fiber Patch Cables should we use in a harsh environment?

With the rapid development of optical communication, more and more fiber optic cables are increasingly used in different environments. Under harsh conditions, the ruggedness and durability of common fiber optic cables cannot meet operators’ requirements, especially for exceptional demanding applications. This post mainly introduces IP67 waterproof fiber optic cable & armored Fiber Patch Cablesuitable in harsh environment. All the types of waterproof fiber optic cables are available in Fiber-Mart.

The two fiber patch cables are armored fiber patch cable and IP67 fiber patch cable. As most fiber cable failures are usually caused by fiber breaks and contaminants, the fiber cable and the termination points of the fiber links should all be well protected. And the two types of fiber cable can perfectly meet most requirements of harsh cabling environment.

IP67 Fiber Patch Cable

IP67 waterproof fiber optic patch cable can be used in harsh environment, providing more convenience and extra protection for network systems. Even if there are various patch cables available on the market, which can be used in different applications, in most cases, they can only be installed in relatively protected environment where stay away from liquid, chemicals and animal biting. What if I want to use it in military network or extremely harsh environment? The following text will introduce a saviour in hostile surroundings—IP67 waterproof fiber optic patch cable.

Overview of IP67 Waterproof Fiber Optic Patch Cable

Waterproof fiber optic patch cable is mainly used in outdoor connection. It is designed with a stainless steel strengthened waterproof unit and armored outdoor PU jacketed cables. It can resist high temperature, and is suitable for use in harsh environments. Similar to standard fiber optic patch cables, waterproof fiber cables also have various types, including simplex, duplex, 12 fibers, 24 fibers, and various kinds of connect interfaces are optional, such as LC, SC, FC, ST, MPO, etc.

IP67 waterproof fiber cable meets ODVA (Open DeviceNet Vendors Association) standards and the IP66/67 environmental sealing ratings. IP67 waterproof fiber jumper connectors are designed according to the IEC60603-7 interface standard, which allows mating to other similar mechanical locking systems. In all, IP67 waterproof fiber optic patch cable is a low-cost and ideal alternative for industry, FTTA, or other harsh environmental conditions.

Why & Where to Use IP67 Waterproof Fiber Optic Patch Cable?

Compared to common fiber optic cables, IP67 waterproof fiber cables are endowed with the following features:

Corrosion-resistant, waterproof, dust-proof

High temperature stability, low insertion loss

Easy operation, reliable and cost-effective installation

Thread locking mechanism to ensure long-term reliable connection

Long-lasting and durable

Rugged design for extreme environments

High sealing performances for vacuum & under water applications

All of the above features make waterproof fiber cables suitable for outdoor application, such as:

Emergency repair quick connection system

Radio and television industry

Military exercise communication devices

Power industry emergency communication system

Oilfield, mining communication connection

Remote wireless base station

Railway signal control application

Intelligent substation communication

Video monitoring system

2.Armored Fiber Patch Cable

Unlike traditional fiber patch cables which are fragile and usually need careful operation, armored fiber patch cables are usually much more durable and flexible. Armored fiber patch cable usually has two jackets, one inner jacket and one outer jacket, between which there is a build-in steel tube. Some vendors also provide armored fiber cables with aluminum tube. This robust metal tube can provide optical fibers inside armored fiber cable from the impact and bite from animals. The most commonly used designs of armor used in armored fiber cables are interlock and corrugated. For most outside plant applications, the corrugated armored fiber cables are suggested. Now a lot of armored fiber patch cable uses interlock armor. During operation in data center, armored fiber patch cable can provide a more flexible cabling environment, because it has bend restrictor which can provide optical fibers from over bending. The following picture shows the structure of an armored fiber patch cable.

With its durability and flexibility, armored fiber patch cables and armored fiber cable are widely deployed in today’s network. For data center applications, there is a wide selection of armored fiber patch cables, which are available from different connector type, fiber type, jacket type, fiber count, etc.

Conclusion

It is usually inevitable to deploy fiber cables in harsh environments for both indoor and outdoor applications. Rodents, like squirrels in outdoor and rats in data centers, are cable destroyers which like to bite or chew fiber optic cables. Except that, there are also many other challenges which can harm fiber optic cables and cause fiber failures, like dusts, water or other liquid, accidental impact, etc. Thus, enough protection should be provided for fiber optic network. Two types of fiber patch cables, which are specially designed for harsh cabling environments, can easily find in Fiber-Mart. Welcome to contact with us: product@fiber-mart.com.

Parameter setting of OTDR optical fiber test method

OTDR is the main instrument in the field of optical fiber testing technology. It is widely used in the maintenance and construction of optical cable lines. It can measure optical fiber length, optical fiber transmission attenuation, joint attenuation, and fault location. OTDR has the advantages of short test time, fast test speed, and high test accuracy.

Optical Time Domain Reflectometer (OTDR), using the method of optical time domain measurement, emits a certain pulse width of light into the tested fiber, and detects the Rayleigh scattering (Rayleigh scattering) and Fresnel reflection (Fresnel reflection) optical signal power along the time Axis distribution, draw OTDR curve, to measure various optical cable and joint parameters to locate optical fiber fault points, and understand the distribution of optical cable loss. The following takes fiber-mart.com OTDR tester as an example to analyze and explain.

1. Test wavelength selection

Since OTDR is for optical fiber communication, select the test wavelength before performing fiber test. Only 1310 nm or 1550 nm is selected for single-mode fiber. Since the 1550nm wavelength has a much more sensitive influence on the bending loss of the fiber than the 1310nm wavelength, it does not matter. Whether it is fiber optic cable line construction or fiber optic cable line maintenance or experimentation and teaching, use OTDR to test the entire fiber backscatter signal curve of a certain optical cable or a certain optical fiber transmission link. Generally, the wavelength of 1 550 nm is used.

The shape of the test curves at 1310nm and 1550nm wavelengths is the same, and the measured optical fiber connector loss values ​​are basically the same. If no problems are found in the 1550 nm wavelength test, then the 1310 nm wavelength test must be no problem.

Choosing the 1550 nm wavelength test, you can easily find whether there is excessive bending of the fiber throughout the entire process. If a large loss step is found somewhere on the curve, repeat the measurement with a wavelength of 1310 nm. If the loss step disappears at a wavelength of 1310 nm, it means that there is indeed an excessive bending situation, which needs to be further searched and eliminated. If the loss step is the same at the 1310 nm wavelength, there may be other problems in the fiber, which need to be found and eliminated. In the single-mode optical fiber line test, the 1550 nm wavelength should be selected as much as possible, so that the test effect will be better.

2. Test range selection

The range of the OTDR refers to the maximum distance that the abscissa of the OTDR can reach. The measurement range should be selected according to the length of the optical fiber under test. It is better for the measurement range to be 1.5 times the length of the optical fiber under test. When the range is selected too small, the display of the optical time domain reflectometer is not comprehensive; when the range is selected too large, the abscissa on the display of the optical time domain reflectometer is compressed and can not be seen clearly.

According to the actual experience of engineers and technicians, when the test range is selected so that the backscatter curve accounts for about 70% of the OTDR display screen, both the length test and the loss test can get a better direct-view effect and accurate test results.

In the optical fiber communication system test, the link length is several hundred to several thousand kilometers, the relay section length is 40-60 km, and the single-reel optical cable length is 2 to 4 km. A reasonable selection of the OTDR range can get good test results.

3. Test pulse width selection

Setting the light pulse width too large will produce strong Fresnel reflection, which will increase the blind area. Although the narrow test light pulse has a small blind area, the light power of the test light pulse is too narrow, and the corresponding backscatter signal is also weak. The backscatter signal curve will be undulating and the test error is large. The set optical pulse width must not only ensure that there is no excessive blind zone effect, but also ensure that the backscattered signal curve has sufficient resolution and can see every point along the optical fiber.

Generally, according to the length of the fiber under test, an appropriate test pulse width is selected first, and an optimal value is determined from the pre-test once or twice. When the distance of the tested fiber is short (less than 5 000 m), the blind area can be less than 10 m; when the distance of the tested fiber is longer (less than 50,000 m), the blind area can be less than 200 m; the distance of the tested fiber is very long (Less than 2 500 000 m), the blind area can be as high as more than 2 000 m.

In single-disk testing, proper selection of the optical pulse width (50 nm) can make the blind zone less than 10 m. By taking the average of two-way test or multiple tests, the impact of the blind zone will be smaller.

Generally speaking, the longer the averaging time, the higher the test accuracy. In order to increase the test speed and shorten the overall test time, the test time can be selected within 0.5 to 3 min.

In the optical fiber communication connection test, a satisfactory result can be obtained by choosing 1.5 min (90 s).

If Fiber-mart OTDR is used for testing, the recommended duration is 1min (60s).

Only by accurately setting the basic parameters of the test can conditions be created for accurate testing.

Safety instructions before fiber optic testing

Hello everyone, today we will discuss with you the safety instructions before fiber optic testing. Some people may not understand why the safety instructions of the optical fiber should be emphasized. This is because once the operation is improper, it will not only cause irreversible damage to the naked eye, but also affect the service life of the optical fiber inspection equipment, or even directly damage the equipment.

01.How to avoid damage to the eyes

• Under no circumstances should you look directly at the optical fiber.

• The wavelength used is invisible to the naked eye (the light that actually transmits data is invisible to the naked eye).

• If the power of the energized optical fiber is large enough, the light emitted by it will cause permanent damage to eyesight.

• If the equipment currently in use is occasionally exposed to its radiation, it will not cause damage to eyesight.

• If you are told that the optical fiber is not energized, please treat it as if it is energized.

• Never stand in front of an optical fiber patch panel unless all optical fiber connectors are equipped with protective caps.

• Comply with the safety requirements set by your organization.

02.

On the device level of fiber inspection

• The equipment test recommendations are all passive tests, that is, there should be no light in the optical fiber.

• Light on the optical fiber will cause inaccurate testing.

• If there is too much light, it will damage the optical power interface of the test instrument.

03.

Choose the most suitable test instrument

Why is it strictly forbidden for us to directly observe whether the light source has output during the test? Because the wavelengths used in optical communications are all invisible wavelengths, the wavelengths of multimode fiber transmission are 850nm and 1300nm, and the wavelengths of single-mode fiber transmission data are 1310nm and 1550nm, so even if we observe with the naked eye, there is no light output. , But in fact, this kind of light may cause permanent damage to human eyes, so be careful.

Of course, as long as we pay attention to the above two safety issues, it is still very safe to use the fiber tester itself. Of course, in the process of use, even if there is a strong light device at the opposite end, the power meter of Fluke Networks still has a large range. It will be easily damaged. At the same time, the OTDR type instrument will automatically give an alarm, prompting that the opposite end is detected and the test cannot be performed, which has a good protective effect, so there is no need to worry about the instrument being damaged.

Whether is worth to Use EDFA Amplifier in Long WDM System?

Introduction to EDFA Amplifier

EDFA amplifier, also referred to as erbium-doped fiber amplifier, is basically composed of a length of Erbium-doped fiber (EDF), a pump laser, and a WDM combiner. When it works, the pump laser with 980 nm or 1480 nm and the input signal around 1550 nm can be combined by the WDM combiner, then transmitted and multiplexed into the Erbium-doped fiber for signal amplification. The pump energy can be transmitted in the same direction as the signal (forward pumping), or the opposite direction to the signal (backward pumping), or both direction together. And the pump laser can also using 980 nm or 1480 nm, or both. Taking the cost, reliability and power consumption into account, the forward pumping configuration with 980nm pump laser EDFA amplifier is always the first choice to enhance the signals for a long WDM system.

Currently, utilizing WDM technology to deploy the optical network has received widespread attentions, which enables higher capacity for data transmission. However, the technology is also limited by the transmission distance. When deploying a long WDM system, the signal power would still become weak due to the fiber loss. In order to address the issue, using EDFA amplifier to directly enhance the WDM signals would be a good choice for current and future optical network needs. The optical network combining WDM technology and EDFA module together can transmit multiple signals over the same fiber, at lengths up to a few hundred kilometers or even transoceanic distances. To better know how does EDFA amplifier work in the long WDM system, let’s learn the EDFA amplifier knowledge and analyze the performance of WDM system bonding with the EDFA module.

Analysis of WDM Network Without EDFA Amplifier

Before analyzing WDM network deployed with EDFA amplifier, it is necessary to know the basic configuration of an original WDM network, as shown in the figure below. We can learn that four signals from different channels are combined by the optical combiner. And then, the integrated signals are transmitted through an optical fiber. Thirdly, the signals are split into two parts by the splitter. One part passes through the optical spectrum analyzer for analyzing signals, and the other one goes through the photo detector to be converted into electrical signal and then be observed by the electrical filter and scope. However, in the process, the signal power gets highly attenuated after being transmitting at long distance.

Analysis of WDM Network Using EDFA Amplifier

By using the EDFA amplifier, we can easily overcome the attenuation of long WDM network. From the following figure, we can learn that EDFA amplifiers act as booster amplifier and pre-amplifier to enhance the signal, so that system will no longer suffer from losses or attenuation. Therefore, if you need to deploy a long WDM system, it is highly recommended to deploy the EDFA amplifiers in the system that features flat gain over a large dynamic gain range, low noise, high saturation output power and stable operation with excellent transient suppression. It is an undoubtedly ideal solution with reliable performance and relatively low cost to extend the WDM network transmission distance.

Conclusion

It is well know that the signal power would be greatly attenuated when the transmission distance is long enough. Hence, when deploying a long WDM network, it is definitely necessary to use the EDFA amplifier to enhance the signal strength, allowing for the long transmission distance. As a preferable option, the EDFA amplifier with very low noise is relatively insensitive to signal polarization and easy to realize signal amplification.