Author: Fiber-MART.COM

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Mode Conditioning Patch Cable Testing

Mode Conditioning Patch Cable Basics

Mode conditioning patch cables, sometimes also called mode conditioning patch cord (MCP), are built in the form of a simple duplex patch cable. They are designed for Gigabit Ethernet multimode applications at the 1300nm wavelength. Generally, this patch cord consists of a duplex common connector on each end of a cable assembly with a single-mode to multimode of fiber-mart fiber connection in one of the two legs.

In summary, this type of patch cable has three distinctions when compared with common patch cables.

The first one is its structure that we have mentioned above. It features rugged construction with a permanent low profile of fiber-mart closure which helps light go through the fiber core precisely.

The second is the reason why they are needed. Common fiber cables are the medium of light signals. However, when transceiver modules used in Gigabit Ethernet (1000BASE-LX) launch only single-mode (1300 nm) long wave signals, problems arise if an existing network utilizes multimode cables. And then mode condition patch cord comes to aid, making the transmission between single-mode and multimode fibers go on wheel.

The last difference of mode conditioning patch cord is its deployment method. Unlike common fiber cables, mode conditioning patch cord usually needs to be used in pairs. So these cables are usually ordered in even numbers.

Testing Methods of Mode Conditioning Patch Cable

Testing a mode conditioning patch cord for insertion loss is similar to testing any standard fiber cable assembly. If the system in which a mode conditioning patch cord is correctly installed does not function properly, simple steps can be taken to rule out the mode conditioning patch cord as the root cause. Here are the steps.

Testing the Multimode/Multimode Leg of Mode Condition Patch Cord

1. Remove the MCP from the system.

2. Reference out a multimode (MM) test jumper using a 1300nm wavelength multimode source.

3. Verify whether the connector on the receiver (RX) end of the MM reference jumper is good. Connecting the MM reference jumper to the OTS TX, and connecting another same jumper to another OTS RX. Then link the two MM fiber jumpers and measure the insertion loss across the multimode connector pair (just like the following picture shows). This value should be < 0.5 dB.

4. Replace the second MM reference jumper connected to the OTS RX with a multimode/multimode leg of MCP (shown a picture below). Measure insertion loss across this multimode connector pair. This value should be < 0.5 dB too.

Testing the Single-Mode/Multimode Leg of the Mode Conditioning Patch Cord

1. Repeat the same three steps mentioned above to measure the insertion loss across the single-mode connector pair (the value < 0.5 dB). The difference is to do it with two single-mode fiber jumpers.

2. Remove the single-mode jumper from the OTS RX, and then connecting the OTS RX to a MCP cord. Make sure the single-mode fiber part of the MCP connecting with the single-mode reference jumper, like the following picture shows. Measure the insertion loss across the single-mode connector pair.

3. Remove the connector of MCP from the OTS RX, and link the multimode fiber part of the MCP with OTS Rx using a multimode jumper used in the in the previous section. Showing in the below picture.

4. Measure insertion loss. This loss is the insertion loss of the multimode connector pair. This value should be < 0.5 dB.

5. The total insertion loss of the MCP is the sum of the loss across the two connector pairs. If the insertion loss is < 1.0 dB, then the MCP cord is functioning properly.

If the MCP cord was mistakenly reversed in the system, then there will be a very high attenuation (on the magnitude of up to 45.0 dB), which would occur resulting in severely degraded signal strength.

Notes: In the whole testing process, if the insertion loss is not < 0.5 dB, then you should separate connector pair and clean them for the second measurement.

Conclusion

Mode conditioning patch cable provides a convenient and reliable method of connecting multimode fiber plants with 1000Base- LX based transmission equipment compliant with IEEE 802.3 standards. This article introduces a simple method to test mode conditioning patch cable in network system. Hope it may help you.

Attaching More Importance to Fiber Optic Adapter

Fiber optic adapter is a small but critical, part of hardware in the fiber optic cabling system. Available for more than a decade, the fiber optic adapter has been a relatively stable device with no really revolutionary breakthrough in its technology, and its importance is often overshadowed by connectors, but product manufacturers continue to stress the significant role that these devices play in overall interconnection performance.

Getting to Know the Concept of Fiber Optic Adapter

Fiber optic adapter is often used to join two terminated fiber optic cable or pigtails together, or to form a fiber optic jack on a wall plate or panel for patching. Like the copper cable adapter, it creates a permanent mating point somewhere for users to plug into as needed. Fiber optic adapter is also called as fiber coupler, it allows fiber optic patch cables to be attached to each other singly or in a large network, which permits many devices to communicate at once.

Note: fiber optic adapter and fiber optic coupler shape a little differently—if the two fiber assemblies to be connected have different style connectors, then we always call adapter; on the contrast, the two patch cables have the same style connectors, we call adapter. This can be clearly distinguished in the following image.

How Do Fiber Optic Adapter Work?

Unlike a copper connection that two copper conductors can be joined directly by a solder or by connectors that have been crimped or soldered to the wires, the key to a fiber connection is the precise alignment of each fiber core. This alignment is achieved by two precision components: the ferrule within each connector and the alignment sleeve within each adapter as shown below. The alignment sleeve is the critical component in an interconnection, which is aimed to bring together the ferrules of the two connectors being mated within the adapter’s sleeve and at its approximate midpoint. The performance of the adapter, defined as how well it aligns two connector ferrules, is determined by the amount of spring force in, and the tolerance of, the split sleeve.

Three Common Fiber Optic Adapter Types

According to different shapes and structures, fiber optic adapters can be classified in several types, such as bare fiber optic adapter, mating sleeves and hybrid fiber optic adapters. The following text will introduce them respectively.

Bare Fiber Optic Adapter—Bare fiber optic adapter is structured with optical fibers on one side and the adapter on the other side, which is used to link the bare optical fiber cable to fiber optic equipment. The adapter side is a connector that can plug into the devices and enables a quick and easy termination for the optical fiber, making it widely used for emergency situation for fast and temporary fiber optic or urgent connection. According to the connector style on the fiber patch cable, there are LC, SC, FC bare fiber adapters available on the market as shown below.

Mating Sleeve—Mating sleeve means the fiber optic adapter is used to connect the same type of fiber optic connectors as shown in the image below. Bare fiber type and plug-in type are available for the mating sleeve. The LC, SC, FC fiber optic adapter are the common mating sleeve types that we often see in networking applications. LC adapter greatly increases the density of fiber optic connector, SC adapter enables a high precision alignment with a low insertion, return loss and back reflection, and FC adapter is easy to operate but sensitive to dust.

Hybrid Fiber Optic Adapter—Unlike mating sleeve, hybrid fiber optic adapter provides interconnections between two different fiber connector types as shown below. It includes male-female and female-female hybrid fiber adapter. Female-to-female hybrid adapter is with two different ends, which is bulk type hybrid fiber adapter, such as FC female at one end and ST female at the other end. Male-to-female hybrid adapter is built out type with a connector plug end and an adapter socket end. Hybrid fiber adapter is often with compact size and widely used for network environments, integrating different configurations and networks.

Conclusion

Don’t look down upon any components in telecommunication applications, since any small devices play an important role in connection, and improving work efficiency, like fiber optic adapter that we have mentioned above. Choosing the right fiber adapter type, you have to check the fiber optic patch cable you need to connect.

Two Suggestions for Deploying SFP+ Twinax Cable

Have you ever used the Cisco SFP+ twinax copper cable for connecting Cisco switches, as a cost-effective alternative to Cisco SFP+ transceivers for short-distance, high-speed connection? Or choosing other branded SFP+ twinax cables to connect their corresponding devices? In fact, SFP+ twinax cable becomes much more popular than ever before for its lower cost and easier installation than the SFP+ transceiver. You only need to incorporate the SFP+ twinax cables into the physical infrastructure directly, then the connection can be finished without any additional signal processing or conversion. However, although the SFP+ twinax cable is very easy to install, there are still two suggestions you should pay attention to if you choose it to deploy 10G short-distance connection.

Design the Length of the SFP+ Twinax Cables Your Network Needs

Before deploying your 10G short-distance connection, it is very important to design and calculate the length of the SFP+ twinax cables your network needs, avoiding many cables waste or lack of cables when deploying. How to calculate it? Just taking the single 84 in. 45 RU cabinet shown in the following figure as an example. As the cabinet is fitted with 2 top of rack switches and 20 2U servers with dual SFP+ NICs (Network Interface Cards), totally 40 SFP+ twinax cables are required. If you prepare to deploy SFP+ twinax cables in the cabinet, you should firstly calculate the longest connection from the top to the bottom of the cabinet, which is about 7 ft. or 2.1 m, and secondly the connection to any port on either end, approximately 1.5 ft. or 0.45 m. Then you can conclude that the longest cable required to reach the farthest port is 2.1+2×0.45≈3 m. Hence, the 3m SFP+ twinax cable should be long enough to connect any two ports within the cabinet.

Use Cable Management Tools to Support the SFP+ Twinax Cable

Since the bundled cable would be very heavy and tend to sag over time, the cable management tools like cable managers, strain relief bars and cable ties are the vital components to support the SFP+ twinax cables. Firstly, there is no doubt that the cable manager is designed for better cable management, as a very commonly used solution. And secondly, how about the strain relief bar? From its name, it is easy to learn that it is to support the cable by providing strain relief, which also facilitates the correct alignment of cable and connector into the port. Meanwhile, the strain relief bar also has the ability to keep the cables away from the spaces directly behind the server and switch equipment, reducing the thermal resistance through the equipment and promoting the effective cooling and airflow. Thirdly, cable ties should be used to hold the SFP+ twinax cables together and tie them to the strain relief bar and cable manager, although they looks so small and unimportant. What’s more, the cable tie installation should be done carefully to firmly place the cables, so that the cables will not move, and also not so tight as to deform or stress the cable jacket.

Conclusion

We all can’t deny that the SFP+ twinax cable provides an ideal low cost, low power and low latency solution for 10G short-distance connection deployment. In details, the cost of SFP+ twinax cable solution is up to three times less than that of fiber optical solution, the power it consumes is up to 50% less than that of current copper twisted-pair solution, and the latency is also lower than that of current copper twisted-pair solution. Furthermore, it features the smallest 10G form factor, as well as the overall cable diameter, designed for higher density and optimized rack space in 10G uplinks and 10G Fiber Channel SAN and NAS input/output connections. In short, the SFP+ twinax cable is an ideal solution to deploy 10G short-distance connection. If you are decide to deploy it, you are suggested to design and calculate the length of the SFP+ twinax cables your network needs and prepare the cable management tools to support the SFP+ twinax cables.

Why Choose HP Compatible SFP+ Transceivers?

In optical communication networks, optical transceivers are some of the most fundamental pieces of hardware for a smooth network. Nowadays, as telecommunication market is surrounded by a sea of fiber optic transceivers of different brands, originals or third-party ones, users are met with many choices. But since many name-brand networking companies charge too much for their transceivers, in most cases, users often buy smart, plug-and-play, and hot-swappable compatible transceiver modules to save money. For instance, if you’re in need of 10GBASE-LR SFP+ for your HP networking, you can turn to Fiber-mart.com for 100% HP compatible SFP+ transceivers (JD094B) which deliver the same value and costs you only a few, US$ 48.00.

Most people often hear such a question: Will I be able to use the existing equipment with the new wiring? The answer is certainly yes. Actually, a third-party fiber optic transceiver is fully compatible with name-brand hardware. There’s simply no difference between good quality third-party ones and the original ones. In this article, I will list several reasons why you should choose HP compatible transceivers, including the compatibility, cost, and support.

100% Compatibility

One thing that a lot of people don’t really realize about optical networking equipment is that there are only a host of factories in the world which are certified to produce it. As a matter of fact, anyone who supplies top-grade optical transceivers is getting them from the same few vendors. And Fiber-mart.com uses them too.

HP compatible SFP+ transceivers are fully MSA-compliant, so they adhere to all relevant standards for optical equipment. Take JD094B for example, this HP compatible 10GBASE-LR SFP+ works at a wavelength of 1550nm over single-mode fibers (SMfiber-mart), with a maximum link length at 40km. All these performances are just the same as what can be expected from the original HP SFP+ transceiver. Neither your HP networking will detect the difference, nor you can tell the difference, since the only difference lies in the name on the package.

Carrier-Grade Quality

Some companies use the exact same ODMs (original design manufacturers) that the major switch OEMs (original equipment manufacturers) use. However, since optical transceivers are the primary business for some third-party transceiver companies, they may understand which ODMs provide the highest quality part for a given data rate or transport protocol. It is not inconceivable for some third-party optics companies to provide more reliable components than those offered by the major switch OEM companies.

Low Cost

The lower costs of third-party optics really cannot be overstated. Typically third-party transceivers cost substantially less than name brands. Why you pay hundreds of dollars for a device that only cost much less, say dozens dollars from third-party? In many cases, a full loadout of third-party transceivers can shave so much money off of an upgrade budget to fund entirely new pieces of hardware. Or they can put a piece of equipment within range, which wouldn’t have been if name-brand ports had to be purchased. There’s no compelling reason to over-pay for the name brand optics.

Reduced Inventory Cost Due To Interoperability

By definition third-party providers of optical transceivers are not tied to a specific switch or router platform. Therefore, their optics will typically interoperate across multiple platforms. This means one specific inventoried part number can be used in both a HP switch and a Cisco switch, as an example. Thus, this approach effectively reduces sparing inventory as well as the operational headaches associated with maintaining inventories for each switch platform.

Instant Shipment & In-stock

Since selling transceivers is the primary business for most third-party transceiver companies, most strive for immediate availability of product. Fiber-mart.com keeps a full stock of our transceivers in-house and ready to ship. There is no complicated ordering process, and once you’ve made an order, you don’t have to wait days or weeks for the items to be delivered. Usually, the products are shipped the same day when you place an order.

Conclusion

HP compatible SFP+ transceivers are cheaper, 100% compatible and in large stock. Whether you need 10GBASE-LR，10GBASE-ER ports, or 10BASE-SR, Fiber-mart.com can meet your needs rapidly for lower prices, no waiting. Certainly, HP compatible SFP optics are also available here, like HP J4858C. For more information about HP compatible transceivers, you can visit Fiber-mart.com directly.

Is the Quality of Chinese Fiber Optic Products Low?

We frequently hear bad things about fiber optic products from China. It has become a trend to abuse Chinese quality. Here I am not going to justify the low-quality fiber optic products coming out of China. Of course, I know there are low-quality Chinese products. Are all the products coming out of China low in quality? Why there is a huge cry against Chinese quality?

It may be partially true in the case of commodity products, but is it possible to deliver low quality fiber optic products to the customers and survive in the market? I think it is almost impossible for a supplier to deliver low quality fiber optic products to dispatch to the customer and force him to use in the network. Fiber optic networks are tested to meet transmission requirements as per international standards. The products used in the fiber optic network need to possess certain minimum characteristics in order to carry optical signals. If a network component fails to carry optical signals, that can not be used in the network.

Characteristics of both active and passive components are well defined and documented in international specifications such as ITU-T and IEEE. Network builders refer these specifications and build their networks based on these standards. A network except for some local area networks, can not stand alone. It somehow becomes part of a bigger network and must communicate with the outside network, which we can call the global network. And as we know, networks must follow certain protocols. If a network component can do the job well as per the defined standards and protocols, we say it is compatible. This compatibility is the minimum quality that is required for the component.

Now, I don’t think that any of the network operators, system integrators or contractors will choose a component that is not compatible with their network. When choosing compatible components one of his/her primary concern will be to reduce the cost of purchase. That is the duty of a good procurement team. Supplier’s intention would be to get more price to his product while the buyer’s intention would be to get a low-cost product. Buyer’s technical team should find a balance between quality and product cost. Considering technical requirements, compatibility, and cost, they decide the vendors. In this process, how a low-quality fiber optic network product supplier can win the supply contract?

Presence of plenty of manufacturers especially from China is one of the reasons for the availability of low-cost products. ‘Low Cost’ does not necessarily mean ‘Low Cost’. Low cost is the result of competition in the market and product manufacturing cost, which includes manpower costs. Low waged labor does not mean low quality and highly paid workers does not guarantee high-quality products. Mass production facilities and low wages are some of the major reasons for low-cost Chinese fiber optic products.

We need to understand the reason behind the cry against Chinese quality. There must be a vested interest group to stamp Chinese fiber optic products with the label of ‘Low quality’. They will be the beneficiaries if customers stop buying Chinese fiber optic products.

What to do (and what NOT to do) in your fiber optic cable assembly polishing process

As you probably know, the polishing process is an extremely important step in the manufacture of fiber optic cable assemblies. Your polishing process ensures your fiber optic connectors meet certain geometric parameters, industry specifications, and/or customer requirements.

When I visit fiber optic cable assembly houses, I help our customers set up their polishing process and, together, we determine the exact requirements for every step in the polishing process to support their unique application. While training customers, I often address common questions revolving around the polishing process: how to prevent film from moving, how much water to use, and how to establish good cleaning techniques to extend the life of the lapping (polishing) film.

Q.  “HOW DO WE KEEP THE POLISHING FILM FROM MOVING?”

A.  When fiber optic cable assembly houses set up a new polishing machine and establish their polishing process, they often find that film slipping or coming off the pad is an issue. To provide uniform polishing, film should never move on the polishing pad. If the film moves with the revolutions of the polishing machine’s platen (the turntable), then you’re not accomplishing anything.

Everything may be spinning, but you’re not actually polishing the connectors. It’s extremely important to overcome this issue! In fact, this is the first thing I show people when I teach them how to polish connectors. The following tips offer pointers.

Helpful tips:

The rubber polishing pad has two surfaces that can be used: a highly polished side and a dull, unpolished side. Place the lapping film on the polished side of the rubber pad – without any liquids. This process relies on “stiction” (adhesion of the film to the pad). First, though, you need to ensure the shiny surface of the polishing pad is absolutely clean. Use a lint-free wipe and isopropyl alcohol (IPA) as a solvent to remove dirt and oils. As long as the pad’s surface area is clean – and the polishing film is clean – you will have successful stiction. After you lay the film on the rubber pad, remove air bubbles by using a circular motion with the lint-free wipe.

If you’re using a glass plate, that’s a different animal! If your process requires the use of a glass plate with a non-PSA-backed film, you can apply a thin film of liquid – a combination of IPA and distilled water – to create stiction. Unfortunately, the IPA-distilled water combination doesn’t provide a lot of strength to adhere the film to the glass plate. Take time to remove air bubbles when laying the film on the plate. This will give you adequate stiction to polish on a mechanized polishing machine. Alternatively, you can use a spray-on adhesive, which can be quite messy.

You don’t want the film to slip AND you don’t want the rubber (or glass) pad to slip. During the cleaning process, liquid may seep between the pad and the platen of the polishing machine. When turned on, the spinning and downward pressure can make the pad slip, which can cause poor results. To prevent this, make sure the pad and platen are completely dry prior to the polishing step.

Q.  “HOW MUCH WATER SHOULD WE USE?”

A.  When polishing fiber optic connectors on a fixed platen, water is used as a lubricant on the lapping film. How you apply the water – and how much to apply – needs to be determined when establishing your process.

The following tips address these points. Next, it’s important to train your operators, so they apply water consistently.

Helpful tips:

The majority of the fiber optic industry uses a distilled/deionized-water mix and a few companies use a combination of isopropyl alcohol and pure distilled water as the primary lubricant. Another school of thought is to use soap (liquid detergent) and water, because soap is slippery and creates very low friction. It’s a matter of choice, plus the type of connectors you’re polishing can dictate which type of lubricant you use. In rare applications, certain optical fibers cannot touch water and require the use of exotic lubricants. (Contact Fiber Optic Center at sales@focenter.com if you encounter such a situation.)

How much water should you apply to the film? Some people use a squirt bottle to spray the film. However, squirt bottles tend to flood portions of the film, and do not provide uniform coverage. I prefer using a SPRITZ bottle, which sprays a fine mist uniformly around the film. Using a spritz bottle, moisture is dispersed in a light and even manner and doesn’t pool. How much water to spritz on your film is very much dependent on your application. There’s no tried-and-true formula. I actually define this when I’m with a customer. (Fiber Optic Center sells 16-ounce and 8-ounce ÅngströmSpray Spritzer Bottles.)

What if you use too much water? If too much water is applied, you’ll risk overflow and flooding the platen. Liquid can seep underneath the rubber (or glass) pad and start slipping, and that’s a risk you want to avoid at all costs. Thankfully, today’s quality polishing machines have plates that lock to prevent the pads from spinning, regardless of how much water seeps underneath the pad. In that case, excessive water use won’t hurt your process – if you lock the plate – but it is messier and takes more time to clean between polishing steps. (Click here to view the polishing machines that Fiber Optic Center sells.)

Can you polish successful dry – with no lubricant? Some fiber optic cable assembly houses do, but I do not recommend this.

Certain fiber optic applications require continuous flow of water: one or two drops a second. The polishing machines we sell at Fiber Optic Center have the ability to provide a constant water drip – from one drop to a continuous flow. However, we strongly recommend you do not use running water in your polishing process.