Choose the Right Interconnect Solutions for FTTH Drop Cable Installations

Transcription

1 Choose the Right Interconnect Solutions for FTTH Drop Cable Installations Business White Paper The Network of Networks Jerry D. Jackson Marketing Manager 3M Communication Markets Division

2 Introduction When designing fiber-to-the-home (FTTH) networks, much thought goes into choosing the right architecture for the job. But the hardware that implements the design is equally important. Choosing the right drop cable interconnect solution, for example, directly affects network reliability, operational flexibility and the economics of FTTH deployment. In determining the best solution for a particular FTTH deployment, providers must first decide between splices and connectors. Then, they must choose the best splice or connector for the particular circumstances of a deployment. This paper explores the available interconnect solutions for FTTH drop cables and discusses their advantages and disadvantages in the context of varying deployment circumstances. Splice or Connector? Before deploying a FTTH network, providers must first decide whether to use a splice, which is a permanent joint, or a connector, which can be easily mated and un-mated by hand. This is for both ends of the drop cable the distribution point and at the home s optical network terminal (ONT) or network interface device (NID). Both splices and connectors are widely used at the distribution point. At the ONT/NID, either a fieldterminated connector or a spliced-on factory-terminated connector can be used. Splices Pros: Splices can provide excellent optical performance. Their reliability has been proven by many years of successful deployment in optical networks. Splicing also eliminates the possibility of the interconnection point becoming damaged or dirty, potentially compromising signal integrity, as may happen to a connector end face when it is being handled while unmated. Contaminants can cause high optical loss or even permanently damage the connector end face. Another advantage of the splice is that it enables a transition from 250 µm drop cable fiber to jacketed cable. Cons: The splice s lack of operational flexibility comprises its major drawback. To reconfigure a drop at the distribution point (in the case of one subscriber dropping FTTH service and another one adding it) one splice must be removed, fibers rearranged, and two new fibers spliced. This requires the technician to carry special splicing equipment for simple subscriber changes. In addition, the fiber-handling process may disrupt other customers service. At the distribution point, most cables utilize 250 µm fiber, and it is easy to bend the fiber and cause high optical loss or even break the fiber. Also, if a splice is used at an ONT, there must be space for a tray to hold and protect the splice. This increases the ONT size and potentially the cost. 2 3M Communication Markets Division

3 Best for: Splices are most appropriate for drops dedicated to a particular living unit and when no future fiber rearrangement is necessary. This is typically seen in a greenfield, new construction application where the service provider can easily install all of the drop cables during the living unit construction. Connectors Pros: Connectors provide greater network flexibility because they can be mated and unmated repeatedly, allowing them to be reused over and over again. A technician can easily connect or disconnect subscribers without any tools. The connector also provides an access point for network testing. Cons: Material cost is the connector s most obvious downside. They cost more than splices, although network rearrangement is much cheaper. Therefore, providers must weigh the material cost of connectors along with the potential for contamination and damage against their greater flexibility and lower network management expense. Best for: Due to the connector s ability to be plugged and unplugged multiple times, it can be used to connect different subscribers as needed for distribution points. Because ONTs have a connector interface, a connector must be installed at this location. Therefore, connectors offer flexibility both at the curb and at the home. The spliceless, gel-free 3M Crimplok + Connector combines the performance of fusion splice-on connectors with the speed of mechanical splice connectors. 3 3M Communication Markets Division

4 Choosing the Right Splice Once the decision has been made to go with a splice, providers must decide upon the type of splice. Splicing technology for FTTH deployment falls into two major categories: fusion and mechanical. Fusion splicing Fusion splicing has been the de facto standard for fiber feeder and distribution construction networks. Fusion splicers have been considered to be a solution for FTTH drop splicing, especially considering they provide a high quality splice with low insertion loss and reflection. However, the initial capital expenditures, maintenance costs and slow installation speed of fusion splicing hinder its status as the preferred solution. Chief among its drawbacks is the need to equip technicians with fusion splicing machines. Fusion splicers present a number of drawbacks: Fusion splicers sell for thousands of dollars each, requiring a heavy investment to equip each technician in the field. Specially trained technicians are required to operate them. They require electrical power, such as a battery, which can deplete of charge in the field, adding time and cost to the process. They take time to set up and break down before and after the installation, adding to labor cost. This can significantly impact installation time because at many locations, including at the ONT, only one splice is installed per location. Additional time is needed for the machine to warm up and heat the sleeves that protect the splice, further slowing installation. From an installation time standpoint, fusion splicing can make sense at the distribution point, where many splices are being performed at one time and installation equipment is only unpacked and repacked once. Fusion splicing is best suited, of course, for companies that have already invested in fusion splicing equipment and do not need to purchase additional splicing machines. Mechanical splices and connectors are successfully deployed around the world in FTTH installations. 4 3M Communication Markets Division

5 Mechanical splicing Mechanical splices and connectors are successfully deployed around the world in FTTH installations. According to FTTH Council statistics, 70 percent of global FTTH subscribers live in China, Japan and Korea. Those countries primarily use mechanical connectivity solutions. However, mechanical splicing has not been popular in the United States historically because many providers share a concern that the index matching gel inside the splices can yellow or dry out, resulting in service failures. Over the last 20 years, great strides have been made across the industry in improving gel performance and longevity. A typical mechanical fiber optic splice, such as the 3M Fibrlok Splice, includes a small plastic housing with an aluminum alloy element to precisely align and clamp fibers. An index matching gel, pre-installed at the fiber connection point, maintains a low-loss optical interface, which results in an average insertion loss of less than 0.1 db. Testing shows that the improved gel used in the 3M Fibrlok Splice can perform well in temperature extremes from -40 to 167 degrees F. Global deployments with millions installed in indoor and outdoor locations have shown that mechanical splices can perform well in many environments. The 3M Fibrlok Splice is designed to be installed in the field using simple hand tools. Global deployments with millions installed in indoor and outdoor locations have shown that mechanical splices can perform well in many environments. 5 3M Communication Markets Division

6 Choosing the Right Connector After choosing to use a connector, the provider must decide between a factory-terminated or field-terminated product. Factory-terminated Factory-terminated drop cables can provide high-performing, reliable connections. The controlled manufacturing process provides consistent fiber end-face geometry, resulting in low optical loss. Factory termination also keeps labor costs low by reducing installation time. An excellent application is a patch cord that connects a desktop ONT to a wall outlet box inside the living unit. A key failure point in the network is when the end user accidentally breaks the fiber in the cable that connects the desktop ONT. If this occurs, the patch cord can be easily replaced. However, factory-terminated cables can be expensive compared to field-terminated alternatives. By nature, they are only available in pre-determined lengths. Technicians must carry many different cable lengths in order to be sure they ll have the right length for the job. That can mean a hefty investment in inventory, especially for outdoor cables with special hardened fiber optic connectors. Factory-terminated cables also require a cable management system to store slack cable at the curb or in home. If a connection goes bad, the entire patch cord must be replaced, as opposed to just a connector. This may be acceptable for indoor patch cords, but outdoor drop cable replacement can be expensive considering the cost of aerial or buried installation. Field-terminated The high costs associated with factory-terminated cable inventory expense, the need for slack storage and the preterminated cables themselves have many providers opting for field-terminated connectors where the installation can be customized by using a reel of cable and connectors. Fuse-on connector: Fuse-on connectors use the same technology as fusion splicing to provide the highest level of optical performance in a field-terminated connector. By incorporating the fusion splice inside the connector, the need for a separate splice tray has been eliminated. However, fuse-on connectors share many of the same drawbacks as fusion splicing. They require expensive equipment, highly trained technicians, and packing and unpacking time, and a power source, ratcheting up installation costs. 6 3M Communication Markets Division

7 Mechanical connector: Mechanical connectors provide alternatives to fuse-on connectors for field installation of drop cables. Here are two different configurations: 3M No Polish Connector (NPC) with a mechanical splice and the 3M Crimplok + Connector without a splice, gel or adhesive. The NPC is installed with a simple handheld tool that does not require an electrical power source. Terminating fiber cable using the connectors is fast, easy and requires little training. A single-fiber termination can be completed in less than three minutes, greatly decreasing installation time compared to fusion splicing. The Crimplok+ Connector is a splice-less, gel-free connector. It combines the performance of fusion splice-on connectors with the speed of mechanical splice connectors. The installation process for the Crimplok+ Connectors is faster and less craft-sensitive than the common field-installation method of fusion splicing. Technicians can quickly and easily install Crimplok+ Connectors at the distribution point or the NID/ONT in five minutes or less, using only simple hand tools. Hybrid solution: Depending upon service provider requirements and living unit configuration, a hybrid solution of factory-terminated connector on one end of the drop cable and a field-terminated connector on the other end may be the optimal solution. In this case, the factory-terminated end is plugged into the distribution terminal, and the other end would be trimmed to length with a field connector installed. This enables custom installations where slack cable storage can be avoided while only needing to install one connector in the field, thus reducing labor relative to field installing both ends. However, it does entail extra cost due to the scrap of the cable that was cut off. Terminating fiber cable using the 3M No Polish Jacketed Connector is fast, easy and requires little training. Technicians can quickly and easily install Crimplok+ Connectors at the distribution point or the NID/ONT in five minutes or less, using only simple hand tools. 7 3M Communication Markets Division

8 Summary The drop cable interconnect solution comprises a key component of an FTTH network. Reliable broadband service depends upon robust connections at the distribution point and the NID/ONT. Choosing the right connectivity product can result in cost savings and efficient deployment while providing reliable service to customers. Globally, most FTTH drop cable installations have been and continue to be field terminated on both ends of the cable with mechanical connectivity solutions. The Network of Networks The 3M Network of Networks is a world leader in communication technology, connecting products, people and companies by harnessing the power of more than 45 technology platforms to create customer-centric innovations. From FTTX to xdsl to Wireless. The Network of Networks connects smart grids to smart phones, wind farms to server farms, greenfield to brownfield, wireline to wireless and customers to their goals. To get the Network of Networks working for you, visit 3M.com/Telecom. 3M, Fibrlok and Crimplok are trademarks of 3M Company. All other trademarks listed herein are owned by their respective companies. Important Notice All statements, technical information, and recommendations related to 3M s products are based on information believed to be reliable, but the accuracy or completeness is not guaranteed. Before using this product, you must evaluate it and determine if it is suitable for your intended application. You assume all risks and liability associated with such use. Any statements related to the product which are not contained in 3M s current publications, or any contrary statements contained on your purchase order shall have no force or effect unless expressly agreed upon, in writing, by an authorized officer of 3M. Warranty; Limited Remedy; Limited Liability. This product will be free from defects in material and manufacture for a period of 12 months from the time of purchase. 3M MAKES NO OTHER WARRANTIES INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. If this product is defective within the warranty period stated above, your exclusive remedy shall be, at 3M s option, to replace or repair the 3M product or refund the purchase price of the 3M product. Except where prohibited by law, 3M will not be liable for any loss or damage arising from this 3M product, whether indirect, special, incidental or consequential regardless of the legal theory asserted. 3 Communication Markets Division 6801 River Place Blvd. Austin, TX / Fax 800/ Please recycle. Printed in USA 3M All rights reserved.