HP SFP Transceiver vs Third-Party SFP Transceiver

In order to cut down the costs on the expensive SFP transceiver modules, many users are seeking for a compatible SFP to use. For example, if your network contains HP routers, firewalls, and switches, you might think that only HP SFP branded transceivers will ensure your equipment functions optimally. However, that seemingly reasonable assumption could cost your company thousands of dollars. Compared to the compatible SFP transceiver produced by third-party companies, HP SFP transceiver comes with dramatically inflated price tags while a third-party compatible one is roughly 80 percent less expensive than HP branded SFP transceiver. Although price isn't everything, it's important to know that you're getting your money's worth. That calls for a comparison of what HP SFP transceiver has to offer next to a third-party compatible one.

Performance

Many people worry that the performance of a third-party compatible SFP is not as good as HP SFP. In fact, HP's own branded SFP transceivers aren't the only ones that work well with their other devices. Compatible third-party SFP transceivers are designed with the specifications of HP technology and function smoothly but have no problem with HP devices such as switches, firewalls, and routers. For example, the following JD092B compatible SFP transceiver provided by Fiberstore offers the same function with HP JD092B and it is fully compatible with HP devices. So you needn’t necessarily buy HP branded SFP transceiver to run your system without glitches or snags.  

Failure Rates

Price implies reliability, is it always true? When you pay more for a product, you must expect that higher cost has some added benefits attached. But it is not always the case. Sometimes you're just paying for the brand name. Third-party compatible SFP transceivers often have lower rates of failure than branded HP SFP transceivers, which makes them more reliable but with less money.

Warranty

HP offers a one-year warranty on their branded optical products, plus whatever coverage may be offered under your service contract, for which you must pay separately and these service contracts don't come cheap. But if you have a lot of experience in shopping around, you'll find that many third-party manufacturers of compatible SFP transceivers and resellers even offer significantly better guarantees. It's not hard to find a lifetime warranty for your compatible optical products.

Availability

Time is money. Everyone prefers to get products earlier rather than later. The last thing you concern when trying to construct or upgrade your network is to find out that the SFP transceivers you have paid are on backorder. That kind of situation often happens when you rely on a single brand for the products you need. Expanding your search to a third-party compatible one can make it easier to get your network up and running faster without having to wait for the parts to be restocked.

If you're still hesitant about trying a third-party compatible SFP transceiver, the best way to ensure that you're getting a reliable product at a good deal is to choose a vendor you trust, one with a proven track record of quality products and great customer service. HP compatible SFP transceivers offered by Fiberstore are fully compatible with HP switches & routers. These SFP modules can be mixed and deployed with genuine HP SFP transceivers for seamless network performance and interoperability. We provide a series of HP compatible SFP transceivers as equivalent to J9151A, JD092B, J8177C, J4859B, etc.

Introduction to OTDR

As the use of fiber in premise networks continues to grow, so do the requirements for testing and certifying it. An optical time-domain reflectometer (OTDR) is an electronic-optical instrument used to characterize optical fibers. It locates defects and faults, and determines the amount of signal loss at any point in an optical fiber. This article describes how an OTDR works and the key specifications that should be considered when choosing an OTDR.

How Does an OTDR Work?

An OTDR uses the effects of Rayleigh scattering and Fresnel reflection to measure the characteristics of an optical fiber. By sending a pulse of light into a fiber and measuring the travel time ("time domain") and strength of its reflections ("reflectometer") from points inside the fiber, it produces a characteristic trace, or profile, of the length vs. returned signal level on a display screen. The working principle of OTDR is based on Rayleigh scattering, a small fraction of light spreading in all direction, which is caused when a light pulse encounters the faults and heterogeneity in optical fiber. (as shown in the following picture.)

OTDR Selection Guide

When choosing an OTDR, it is important to select the specific OTDR performance and features according to the required specifications listed below.

• Dynamic Range

The dynamic range of an OTDR determines how long of a fiber can be measured. The total optical loss that an OTDR can analyze is mainly determined by the dynamic range. The dynamic range affects the accuracy of the link loss, attenuation and far-end connector losses. Thus, having sufficient dynamic range is really important. The manufacturers specify dynamic range in different way. The higher the dynamic range, the longer the distance an OTDR can analyze.

• Dead Zones

Dead zone refers to the space on a fiber trace following a Fresnel reflection in which the high return level of the reflection covers up the lower level of backscatter. To specify an OTDR's performance, it is important to analyze the dead zone and ensure the whole link is measured. Dead zones are characterized as an event dead zone and an attenuation dead zone. Event dead zone refers to the minimum distance required for consecutive reflective events to be "resolved" (for example, to be differentiated from each other). Attenuation dead zone refers to the minimum distance required, after a reflective event, for the OTDR to measure a reflective or non-reflective event loss.

• Resolution

There are two resolution specifications: loss (level), and spatial (distance). Loss resolution is the ability of the sensor to distinguish between levels of power it receives. When the laser pulse gets farther out in the fiber, the corresponding backscatter signal gets weaker and the difference between backscatter levels from two adjacent measurement points becomes larger. Spatial resolution is how close the individual data points that make up a trace are spaced in time (and corresponding distance). The OTDR controller samples the sensor at regular time intervals to get the data points. If it takes readings from the sensor very frequently, then the data points will be spaced close together and the OTDR can detect events in the fiber that are closely spaced.

• Pass/Fail Thresholds

This is an important feature because a great deal of time can be saved in the analysis of OTDR traces if the user is able to set pass/fail thresholds for parameters of interest (such as splice loss or connector reflection). These thresholds highlight parameters that have exceeded a warning or fail limit set by the user and, when used in conjunction with reporting software, it can rapidly provide re-work sheets for installation/commissioning engineers.

• Post-Processing and Reporting

Report generation could be another major time saver. For example, some OTDRs with specialized post-processing software allow fast and easy report generation, which might reduce the post-processing time up to 90 percent. These reports also include bidirectional analyses of OTDR traces and summary reports for high-fiber-count cables.

• Your Applications and Users

Some OTDRs are designed to test long distance optical fibers and some others to test short distance optical fibers. For example, if you are to test premises fiber networks where short distance optical fibers are installed, OTDRs designed for testing long distance optical fibers are not suitable. Besides, knowing your users and the time it will cost is also necessary. Because some types of OTDRs are easy to use and some others are complicated to set up.

When selecting an OTDR, you're supposed to take all the above factors into consideration. Fiberstore supplies a wide range of OTDRs available with various fiber types and wavelengths (including single-mode fiber, multi-mode fiber, 1310nm, 1550 nm, 1625 nm, etc). They also supply OTDRs of famous brands, such as JDSU MTS series, EXFO FTB series, YOKOGAWA AQ series and so on. OEM portable and handheld OTDRs are available as well.

Originally published at www.fiber-optic-equipment.com/introduction-to-otdr.html

Link Budget Evaluation Over SMF and MMF

Evaluating a link budget is equivalent to calculating the total loss suffered by a transmitted signal along fiber channels with the minimum receiver power to maintain normal operation. Calculating the link budget helps network architects to identify the feasibility of a physical-layer deployment.

Optical fibers come in several different configurations, each ideally suited to a different use or application. Early fiber designs that are still used today include single-mode fiber (SMF) and multimode fiber (MMF). And the most common optical communication data links include point-to-point transmission, WDM and amplified transmission. This article depicts the rules to be applied in order to evaluate link budget of these optical transmissions over SMF and MMF.

Link Budget for Point-to-Point Transmissions over Multimode Fibers

In this first case, the rule is fairly simple. A few parameters need to be taken into account:
● The minimum transmit power guaranteed (minTx), expressed in dB/m
● The minimum receive power required (minRx), expressed in dB/m
● The loss of optical connectors and adapters (L), expressed in dB
● The number of connectors and adapters (n)
● The normalized fiber loss (FL), expressed in dB/km
● The reach or distance to be achieved (d), expressed in km
With these parameters, the link budget (LB) expressed in dB is given as follows:
● (LB) = (minTx) – (minRx)
This value needs to be compared to the total loss (TL) suffered by the transmitted signal along the given link, and expressed in dB:
● (TL) = n*(L) + d*(FL)
If LB is greater than TL, then the physical deployment is theoretically possible.
In these calculations n is at least equal to 2 since there are a minimum of 2 connectors at each end, L is typically around 0.5 to 1 dB, and FL is of about 1 to 1.5 dB per km.

Link Budget for Point-to-Point Transmissions over Single-mode Fibers

At first, you need to know that the lasers deployed in optical communications typically operate at or around 850 nm (first window), 1310 nm (second window), and 1550 nm (third and fourth windows). In this second case, the calculations are exactly similar to the previous case. Only the numerical values will differ. For single-mode point-to-point transmissions, n is at least equal to 2, L is typically around 0.3 to 0.5 dB, and FL is of about 0.4 dB per km in the second window and about 0.25 dB per km in the third window.

The following drawings show the power budget of a 2km hybrid multimode/singlemode link with 5 connections (2 connectors at each end and 3 connections at patch panels in the link) and one splice in the middle.

Link Budget for WDM and Amplified Transmissions over Single-mode Fibers

In the case of WDM transmissions, passive modules are used to multiplex and demultiplex various wavelengths respectively before and after the signal propagates along the fiber channel. These passive modules introduce additional insertion losses suffered by the signal transmitted.

Additionally, the signal may be amplified and compensated for dispersion, and in this case, the amplifier gain and the dispersion compensation unit's loss need to be taken into account. Dispersion and OSNR (optical signal over noise ratio) penalties suffered by the receiver shall be considered as well.

Therefore all the parameters needed for a proper link budget evaluation are:
● The minimum transmit power guaranteed (minTx), expressed in dB/m
● The minimum receive power required (minRx), expressed in dB/m
● The loss of optical connectors and adapters (L), expressed in dB
● The number of connectors and adapters (n)
● The normalized fiber loss (FL), expressed in dB/km
● The reach or distance to be achieved (d), expressed in km
● The loss of passive add/drop modules (A and D), expressed in dB
● The gain of the amplifier (G), expressed in dB
● The penalty suffered by the receiver (P), expressed in dB
● The loss of a dispersion compensation unit (DCU), expressed in dB With these parameters, (LB) is given as for previous cases:
● (LB) = (minTx) – (minRx)
And the total loss is expressed as follows:
● (TL) = n*(L) + d*(FL) + (A) + (D) – (G) + (DCU) + (P)
Here again, if LB is greater than TL, then the physical deployment is feasible. Please note that for simplicity, only one amplifier, one dispersion compensation unit, and one set of add/drop modules are considered in this example. If more devices are planned to be deployed, their loss or gain should be added or subtracted accordingly in order to calculate TL.

Link budget is a way of quantifying the link performance. And the performance of any communication link depends on the quality of the equipment being used. Thus, when evaluating a link budget, you are supposed to consider the types of applications, the reach to be achieved, as well as the types of optical fibers deployed. For more information about fiber optical link products, please visit FS.COM.

Originally published at www.fiber-optic-equipment.com/link-budget-evaluation-over-smf-and-mmf.html

Available Interconnect Solutions for FTTH Drop Cables

FTTH, short for fiber to the home, is the installation and use of optical fiber from a central point directly to individual buildings such as residences, apartment buildings and businesses to provide unprecedented high-speed Internet access. 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 article explores the available interconnect solutions for FTTH drop cables and discusses their advantages and disadvantages in various deployment circumstances.

Splice vs 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. Both splices and connectors are widely used at the distribution point. At the home's optical network terminal (ONT) or network interface device (NID), either a field-terminated connector or a spliced-on factory-terminated connector can be used.

Splices enable a transition from 250micron drop cable fiber to jacketed cable with high reliability and eliminates the possibility of the interconnection point becoming damaged or dirty. Splices are most appropriate for drop cables dedicated to a particular living unit where no future fiber rearrangement is necessary, such as in a greenfield or new construction application where the service provider can easily install all of the drop cables during the living unit construction.

Connectors are easier to operate and provide greater network flexibility than splices, because they can be mated and unmated repeatedly, allowing them to be reused over and over again. Connectors also provide an access point for network testing. However, connectors 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.

Choosing the Right Splice

Splicing technology for FTTH deployment falls into two major categories: fusion and mechanical.

Fusion splicing is considered to be a solution for FTTH drop splicing, especially considering it provides a high quality splice with low insertion loss and reflection. However, fusion splicing is expensive and requires trained technicians to operate. It is time-consuming and the slow installation speed hinders its status as the preferred solution. Fusion splicing is best suited for companies that have already invested in fusion splicing equipment and do not need to purchase additional splicing machines.

Mechanical splices can perform well in many environments and have been successfully deployed around the world in FTTH installations. A typical mechanical fiber optic splice includes a small plastic housing with an aluminum alloy element to precisely align and clamp fibers. An index matching gel inside the splices maintains a low-loss optical interface, which results in an average insertion loss of less than 0.1 dB.

Choosing the Right Connector

According to the drop cables used, connectors can be divided into two types: factory-terminated and field-terminated.

Factory-terminated
Factory-terminated drop cables can provide high-performing, reliable connections with 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.

Field-terminated
Many providers prefer field-terminated connectors where the installation can be customized by using a reel of cable and connectors, such as fuse-on connectors and mechanical connectors. For example, 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. However, mechanical connectors can provide alternatives to fuse-on connectors for field installation of drop cables.

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.

Why Plug-and-Play Transceivers Are So Popular

Plug-and-play is a technology that allows the operating system to detect and configure internal and external peripherals as well as most adapters. It has the ability to find and configure hardware components without having to reset DIP (dual in-line package) switches and jumpers. Plug-and-play transceivers refer to hot-swappable or hot-pluggable optical transceivers, such as SFP transceivers or XFP transceivers, which can be quickly plugged into an interface of fiber optical devices. Here are the reasons why plug-and-play transceivers play such an important role in data center communications.

Designed to Handle Mission Critical Applications

Plug-and-play transceivers are the basics of linking and transmitting data in mission critical applications which are the foundation of a company's business, like telecommunications company or networking technical company which depend heavily on data center. Therefore it is essential that these applications run efficiently or the entire company will be stuck in trouble. The faster data can reach, the faster decisions can be made. That's why it's so important to ensure that the applications are up and running 99.99 percent of the time. Even if plug-and-play transceivers fail to work well, there is relatively little downtime because the devices can be replaced without powering down the entire system.

Time-saving and Cost-effective

There's nothing worse than a malfunctioning transceiver that needs repair or replacement. Imagine that if you have to redesign an application every time one component malfunctions. Redesigns are not favorable because they are expensive and time consuming. Using plug-and-play transceivers can avoid redesign, because they are highly compatible and can be easily replaced. This is an important factor why plug-and-play transceivers are more popular than standard transceivers, because you can save time and money with plug-and-play transceivers and avoid redesigns that could ruin the efficiency of your work.

Upgrade When Needed

This will allow you to keep your capital liquid and invest in other aspects of your business. When new devices are introduced on the market, it will be easy to drop them into your existing design. Many of the transceivers are 100% compatible and are backed by a warranty. Thus, designers have nothing to fear by waiting to upgrade. If the upgrade doesn't work, they'll be refunded for the cost of the device.

Increase Productivity and Efficiency

As mentioned above, plug-and-play transceivers allow people to replace transceivers easily without completely shutting down their entire system or redesigning the application. When it's not required to power down the device for replacement or repair, productivity and efficiency improves. This is why so many telecommunications company and networking technical company are choosing plug-and-play devices over standard devices, especially the plug-and-play transceivers. Currently, fiber plug-and-play solutions for data center applications are very necessary to transmit data with a high degree of integrity, reliability and efficiency.

All in all, there are so many reasons that plug-and-play transceivers are preferred over standard transceivers. Using plug-and-play transceivers can expand your options. With your options open, there are more opportunities of saving money, upgrading and increasing productivity. And the fact that plug-and-play transceivers are hot-swappable and do not require designers to power down the device is appealing to most people. That's also why so many designers are considering plug-and-play transceivers to increase their functionality.

Originally published at http://www.sfp-transceiver-modules.com/wiki_list

SFP+ Direct Attach Cable

Nowadays, there is an increasing demand for cables which can provide a lower-power means for operation on short fiber optic links or short copper connections such as the SFP+ direct attach cable that will be described in this article.

What Is SFP+ Direct Attach Cable

SFP+ direct attach cable is a fixed assembly that is purchased at a given length, with the SFP+ connector modules permanently attached to each end of the cable. SFP+ direct attach cable provides high performance in 10 Gigabit Ethernet network applications, using an enhanced SFP+ connector to send 10 Gbps data through one paired transmitters and receivers over a thin twinax cable or fiber optic cable. The 10G SFP+ direct attach cable is designed to use the same port as an optical transceiver, but compared with optical transceivers, the connector modules attached to the cable leave out the expensive optical lasers and other electronic components, thus achieving significant cost savings and power savings in short reach applications.

Characteristics of SFP+ Direct Attach Cable

SFP+ direct attach cable is a low cost alternative to traditional fiber and twisted-pair copper cabling in data center deployments. SFP+ direct attached cable provides better cable management for high-density deployments and enhanced electrical characteristics for the most reliable signal transmission. The outstanding advantages are listed as follows:
High speed—support 10 Gbps data rates with backwards compatibility to 1 Gbps
MSA compliant—direct attached compliant and fully conform to the SFP+ MSA specifications
Reliability—RoHS compliant with excellent EMI performance and high reliability
Space saving—offer the smallest 10 gigabit form factor and a small overall cable diameter for higher density and optimized rack space in 10G Ethernet uplinks and Fibre Channel
Cost saving—cost up to three times less than fiber optic solutions, while offering lower latency and consuming up to 50% less power per port than current copper twisted-pair cabling systems
Scalability and flexibility—provide enhanced scalability and flexibility as well as higher density for today's data centers and storage area networks

Types of SFP+ Direct Attach Cable

Generally speaking, SFP+ direct attach cable can be divided into active and passive versions. Active SFP+ direct attached cable is used in active optical system which includes electrically powered switching equipment, such as a router or a switch aggregator, to manage signal distribution and direct signals to specific customers. While passive SFP+ direct attached cable is used in passive optical network which does not include electrically powered switching equipment, but uses optical splitters instead, to separate and collect optical signals as they move through the network. Powered equipment is required only at the source and receiving ends of the signal. Passive cables are cheaper than active cables but have shorter range than active cables, which means that the subscribers must be geographically closer to the central source of the data.

Fiberstore SFP+ DAC Solution

Nowadays, SFP+ direct attach cable is tremendously popular in the market. Fiberstore provides three types of 10G SFP+ cable assemblies: 10G SFP+ passive copper twinax cable (PCC), 10G SFP+ active copper twinax cable (ACC), and 10G SFP+ active optical cable (AOC). Various lengths can be customized according to customers' requirements.

Originally published at http://www.sfp-transceiver-modules.com/wiki_list

XENPAK Transceiver Overview

On March 12, 2001, the module multi-source agreement (MSA) association announced that the XENPAK specification is available for first public review. XENPAK is the first MSA for 10 Gigabit Ethernet. The XENPAK MSA defines a fiber optic or wired transceiver module which conforms to the 10 Gigabit Ethernet standard of the IEEE 802.3 working group. XENPAK transceiver module is a hot-swappable, highly integrated and serial optical transceiver module for 10Gbit/s data transmission applications. It is designed to transmit and receive optical data of link length of 300m, 10km, 20km, 40km and up to 80km. 10G XENPAK solution includes dual fiber XENPAK, CWDM XENPAK and DWDM XENPAK transceivers which enable high port densities for 10 Gigabit Ethernet systems. A 70 pin electrical connector and a duplex SC connector optical interface assure that connectivity is compliant to the XENPAK MSA. CWDM XENPAK transceiver and DWDM XENPAK transceiver are two commonly used XENPAK transceivers in the market.

CWDM XENPAK Transceiver

CWDM XENPAK transceivers are SC duplex receptacle modules and are designed for 10Gb/s Ethernet transmission systems. Wavelengths are selectable from ITU-T standards covering CWDM grid wavelengths: 1470nm, 1490nm, 1510nm, 1530nm, 1550nm, 1570nm, 1590nm and 1610nm. All CWDM XENPAK transceiver modules are MAS compliant, RoHS6 compliant and lead free. Transmitting distance of CWDM XENPAK achieves 40km (ER) and 80km (ZR) with digital diagnostic monitoring. Fiberstore's 10G CWDM XENPAK transceivers are designed for single mode fiber and applied in 10 Gigabit Ethernet and Fibre Channel.

DWDM XENPAK Transceiver

DWDM XENPAK transceivers are SC duplex receptacle modules and are designed for backbone Ethernet transmission systems. For 10G DWDM XENPAK transceivers, wavelengths are selectable from ITU-T channel C-band standards covering 45 DWDM grid wavelengths: 1528.77 nm to 1563.86 nm as specified by the ITU-T. All DWDM XENPAK transceivers are MAS compliant, RoHS6 compliant and lead free. Transmitting distance of DWDM XENPAK achieves 40km (ER) and 80km (ZR) with digital diagnostic monitoring. Fiberstore's DWDM XENPAK transceivers are designed to deploy in the DWDM networking equipment in metropolitan access and core networks.

Installing XENPAK Transceiver

To install XENPAK transceiver, you are supposed to follow these steps:
Step1: Remove the XENPAK transceiver module from its protective packing. (Do not remove the optical bore dust plug until you are directed to do so later in the procedure)
Step2: Check the label on the XENPAK transceiver module body to verify that you have the correct model for the network. (Make sure that the product number matches the desired band and channel)
Step3: Verify that the bale clasp on the front of the XENPAK transceiver module is closed before inserting the XENPAK transceiver module.
Step4: Align the XENPAK transceiver with the opening in the module faceplate, and slide the XENPAK transceiver into the opening until the XENPAK transceiver faceplate is in contact with the module faceplate. (This step ensures that the XENPAK transceiver is fully seated in the module socket)
Step5: Tighten the two captive installation screws to secure the XENPAK transceiver in the socket. Avoid cross-threading or over-tightening the captive screws.
Step6: Remove the dust plugs from the network interface and save the dust plugs for future use. Then remove the dust plugs from the XENPAK transceiver optical bores and save the dust plugs for future use.
Step7: Immediately attach the network interface to the XENPAK transceiver.

Fiberstore manufactures and supplies a complete range of XENPAK transceiver modules which can be customized. In addition, Fiberstore also provides compatible XENPAK transceivers as alternatives to those branded by Cisco, HP, Juniper Networks. The aim is to offer customers high-performance and cost-effective products to fulfill their requirements, contributing this way to the customer's success and satisfaction.

Originally published at www.sfp-transceiver-modules.com/wiki_list