Optical Fiber Fusion Splicing and Its Applications

Author : Colin Yao

What is optical fiber fusion splicing?

Optical fiber fusion splicing is a welded joint formed between two optical fibers. Fusion splicing is a permanent, low-loss, high-strength joint compared with other temporary joint such as a mechanical splice. Optical fiber fusion splices play a crucial role in the optical network.

The Ideal Fusion Splicing Process

The goal of fiber fusion splicing is to create a joint with minimum insertion loss yet with mechanical strength and long-term reliability that matches the fiber itself.

The ideal process of fusion splicing should be fast, inexpensive and should not require expensive equipment. But in reality the fusion splicing process needs trade-offs among different applications and requirements. For example, for undersea telecommunications, long-term reliability is the most important goal for a fusion splicing.

The Advantages of Optical Fiber Fusion Splicing

There are other approaches for interconnecting fibers such as fiber optic connectors and mechanical splicings. Compared to these two, fusion splicing has many advantages as explained below.
1. Fusion splicing is very compact
2. Fusion splicing has the lowest insertion loss
3. Fusion splicing has the lowest back reflection (optical return loss ORL)
4. Fusion splicing has the highest mechanical strength
5. Fusion splicing is permanent
6. Fusion splicing can withstand extreme high temperature changes
7. Fusion splicing prevents dust and other contaminants from entering the optical path

Types of Fusion Splicing

Fusion splicing environment and applications can be roughly divided into three types: 1. Field splicing 2. Factory splicing and 3. Laboratory splicing.

An important example of field splicing is the assembly of undersea fiber cables aboard fiber deployment ships. The example of factory splicing could be the assembly of fiber optic passive devices such as a WDM. An example of laboratory splicing is done by researchers fusion splicing the newest developed fibers to test their compatibility with existing industry standard fibers.

Fiber fusion splicing involves concepts from many subjects including optical waveguide theory, heat transfer, material science, mechanical engineering, fluid mechanics and more.

Introduction to the Fusion Splicing Process

The major steps involved in optical fiber fusion splicing can be summarized as the following.

1. Optical fiber stripping
The fiber cable jacket is removed and then the fiber polymer coating is stripped with fiber optic strippers.

2. Fiber cleaving
The fiber is cleaved with specialized tool called fiber cleaver. Two types of fiber cleaver exist: high precision fiber cleaver for single mode applications and field cleaver for multimode applications. A mirror like almost perfect end face is achieved by this cleaving process.

3. Fiber alignment
The fibers are laterally aligned to each other by step motor in a fusion splicer. This may involve rotating the fibers in polarization maintaining fiber splicings.

4. Fiber welding
The fibers are then heated with electric arc or other methods to the fiber glass's softening point and then both fibers are pressed together to form a solid joint.

5. Insertion loss estimation
The insertion loss is estimated based on the fusion quality and dimensions.

6. Pull tension strength testing
The fusion is pull proof tested when opening the fusion splicer cover.

7. Splice protection with fusion splice sleeve
The fusion splice joint is then protected with a heat shrink tube with a steel strength member inside to form a solid and reliable fiber joint.

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The Secret Of A Successful Underground Fiber Optic Cable Installation

Author: Colin Yao

The two most common outdoor fiber optic cable installations are pole line aerial installation and underground cable installation. Underground cable installation can be buried directly underground or placed into a buried duct.

Direct burial installation:

Direct burial installations are most common for long cross-country installations. The cables are plowed in or buried in a trench; the installation process can be very quick. The most common cables used for direct burial are steel armored outdoor fiber cables.

Underground duct installation:

Fiber optic cables can also be pulled through underground ducts, which protect the cables from harsh environment. Underground duct installation also provides opportunity for future expansion without the need to dig. This is the most common practice in urban areas. Another benefit is that fiber cables without armor can be used which makes the installation even easier.

Preparation before underground cable installation:

1. Obtain proper right-of-way permits
2. Identify existing underground utilities such as buried cables, pipes
3. Investigate the soil condition in order to determine the installation depth, whether duct should be used, the type of fiber cable should be used and plowing equipment needed

Cable Burial techniques:

1. Plowed under

Plowing in a fiber cable is faster than trenched. But this process has to be carefully monitored to prevent from damaging the cable.

2. Trenched

The fiber cable can also be trenched. This process is slower than plowing in; however, it allows a much more controlled cable installation. Trenches can be dug by hand or by machine.

3. Directional boring

Directional boring technique is used where the surface cannot be worked on such as high, railway crossings, etc. Instead, a boring machine is used to bore a several inches diameter hole underneath the surface, a duct is pulling through the hole and then fiber cables pulled into the duct.

Important factors:

1. Cable installation depth: up to 40 inches

The depth that fiber cables should be buried is determined by the soil conditions and surface usage. In colder areas, fiber cables are typically buried below the frost line to prevent the cables from being damaged by ground frost heaves.

2. Keep the trenches as straight as possible

Fiber cable trenches should be straight, and the trench bottom should be flat and level. Backfill can also be used to distribute the cable load evenly and protect the cables.

3. Fiber cable warning labels should be buried directly above the cable

Fiber optic warning cables are typically buried directly above the cables to warn future digging operations. Or concrete slabs can be buried below the warning label but above the cables to provide even more protection.

4. Whenever conducting armored fiber cables are used, they should be properly grounded

In direct burial installations, steel armored fiber cables are often chosen for their strength and protection from rodent bites. A very important thing to keep in mind is to properly ground the cables. They should be grounded at all termination points, splices and building entrances. The cable steel armor should be connected to a ground wire using a compression-type clamp. The cable ground wire is then bolted to a nearby ground terminal strip.

5. Fiber optic cable minimum bending radius should always be observed during installation.

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Everything You Need To Know About Computer LAN (Local Area Network) Backbone Wiring

Author: Colin Yao
:: The Definition of Backbone Cabling

Backbone cabling may be within one building or between buildings on a campus. All wiring between telecommunication rooms is called as backbone cabling.

In many cases, backbone cabling is actually between wiring closets on the same floor of a building, but the more typical case is the floor to floor wiring in a multi-floor building. Many call it vertical cabling in contrast to horizontal cabling.

:: How are backbone wiring implemented?

Typically all hubs, concentrators and switches are placed in the telecom rooms which serve all workstations on that same floor. Backbone wiring then connects the hubs, on to another on different floors.

• Daisy Chain wiring. In a daisy chain wiring, the back bone wiring connects from hub to hub to hub. Daisy chain is a good choice for Token-Ring topology, since it provides convenient ring-in and ring-out connections.

• Star wiring: In a star wiring, the back bone wiring connects all hubs from different floors to a center hub. Star wiring is a good choice for Ethernet which must limits repeater jumps.

For large buildings, telecom rooms are often placed in services shaft, one above the other, distances between telecom rooms are minimal. Thus the backbone wiring from each floor may be concentrated in a single master telecom room and the number of repeater jumps minimized.

:: How is backbone wiring capacity implemented?

Backbone wiring should be terminated in the same manner as horizontal cabling. The backbone cabling should be of same or higher category and type that meets your performance requirements and the safety and fire protection requirements for your installation.

For example, for Cat 5e horizontal wiring, you should use Cat 5e cable or even higher category such as Cat 6 and Cat 7. If you anticipate using your wiring system for multiple applications, double or even triple each backbone wiring run. This will give you ample room for growth and the ability to rapidly respond to new requirements.

:: Fire Safety

Most standard require that all riser cable (cable that goes vertically between floors) be riser rated for its fire and smoking rating. Some even require plenum rated cables.

But one most important thing is - you must properly install fire-stop material on all openings you make between floors, no matter those are cable ports or direct openings.

If you backbone wiring actually involves floor-to-floor cabling in vertical shafts or cable ports, you may need to use special riser cable that has a fire-retardant sheath, certified to meet NEC low-flame requirements. The NEC requires that riser cable meet UL flammability tests to be used in high-rise buildings.

:: Grounding requirement

When pulling cables between far flung telecom rooms or between floors, electrical grounding and bonding requirements must be observed. You can refer to EIA/TIA standards for the proper practices.

:: Advantages of fiber optic cable

Fiber optic cable provides significant advantages over copper cable. Fiber optic cable is not subject to electrical or magnetic interference, and thus may be run in locations, such as elevator shafts or alongside power lines.

In addition, a cabling system may be electrically isolated between buildings or between floors of the same building by using fiber optic cable.

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Creating a Backup Strategy to Avoid Disaster

Author: Sandra Prior

You want all your data files (e.g. Word documents, Excel documents, email, etc.) to be in folders that are all inside a single folder on your hard disk. Windows provides you with a folder named "My Documents" designed for this purpose. In Windows 95/98/ME there is a single My Documents folder shared by all users while Windows NT/2000/XP creates a separate My Documents folder for each login account. Backing up the "WinNTProfiles" folder in NT 4.0 or the "Documents and Settings" folder in Windows 2000/XP will back up the My Documents folders for all users if you are logged in as an administrator.

Many programs default to saving files in the My Documents folder and programs that can’t can usually be set to do so. You will probably want to create new folders under the My Documents folder to keep data from different applications or projects separate. You may need to read the documentation to learn how, but you should set each program to open documents from and save documents to the appropriate folders you have created under the My Documents folder. If you do this consistently you will know where all your data is on your hard disk and won't accidentally miss backing up important data.

Choose what device you will use to back up your data.

The most common devices to back up data have been tape drives, zip drives and flash drives. More recently, CDRW drives (CD read/write drives) are being used for backups. Your decision will be based on how much data you need to back up, what devices you already have that could be used for backups, and whether or not you can purchase a new backup device.

The least expensive devices are Iomega zip drives and disks. Zip disks come in 250MB and 100MB sizes. You must buy a zip drive designed for 250MB disks to use 250MB disks. All zip drives can work with 100MB zip disks. Zip drives come with software for backing up data to zip disks or you can copy the folder that all your data is under ("My Documents" or "Documents and Settings" to a zip disk if it will all fit.

Jaz drives come in 1GB and 2GB sizes and are similar to zip drives but are bigger and cost more. They use the same Iomega backup software as zip drives. You can also use DVD disks which are 4.7gig in size.

CDRW drives can be used like a 650MB floppy disk when using CDRW disks and packet writing software that comes with the drive. The disks you create will be readable only on other CDRW drives or CDR/DVD drives that support the multi-thread standard. All drives capable of reading CDRW disks require software to be installed that supports reading CDRW disks. You should use software that supports the UDF standard (most current CDRW packet writing software does) when writing files on your CDRW drive and install UDF reader software on computers with multithread CD or DVD drives that you want to read CDRW disks. Drives with early implementations of multithread may not be able to read CDRW disks even with UDF reader software installed. Free UDF readers are available from Ahead Software and Roxio. CDRW drives may come with backup or disaster recovery software but you should look carefully at the software bundled with a CDRW drive before purchasing it.

Unlike the previous devices, tape drives are designed specifically for backing up data. They hold more data, 4GB to more than 40GB, and require running a backup program both to backup or restore files. A tape drive cannot be used like a large floppy disk. Windows 95/98/ME does not come with backup software so you must use the software, if any, that comes with the tape drive, or purchase backup software. Windows NT has a backup program that works with most SCSI tape drives. Windows 2000/XP has a backup program that works with any removable media that can be written to from within Windows (e.g. zip, jaz, CDRW) and most tape drives. Tape is the least expensive media for very large amounts of data.

Develop a backup strategy.

You can just copy the files you need backed up onto removable media. This cannot be done with tape, but works with zip, jaz, and CDWR disks. It only works well if all your data fits on a single disk. Using a backup program allows using tape and can span more than one disk or tape if necessary. Backup programs also allow special backup series starting with a complete backup followed by backing up only files that have changed. Initially, assume doing complete backups. Ideally, you should back up your data on a daily basis. This guarantees that you won't lose more than one day's work if your hard disk crashes. In the strategies below, it also means you aren't completely dependent on any one disk or tape for your backups. Removable disks and tapes also go bad.

Strategy One: Gives you one work week of daily backups.

Label five media (disks or tapes) Monday, Tuesday, ..., Friday.
On a Monday, put Monday's media into its drive then copy/backup your "My Documents" folder or "Documents and Settings" folder to the media. Remove the media when all the files have been saved to it.
Repeat step 2 daily using the appropriately labelled media for each day. Erase the data on the backup media from the previous week either manually or through the backup program you are using before performing a new backup to it.
Strategy Two: This is an extension of Strategy One. It gives you one work week of daily backups plus one month of weekly backups.

Label four media Tuesday, Wednesday, Thursday, Friday.
Label five media 1st Monday, 2nd Monday, ..., 5th Monday.
On the first Monday of the month, delete any data already on your 1st Monday media then backup your data to it.
Backups on Tuesday through Friday will be the same as in Strategy One.
On the second, third, fourth, and fifth (if there is one) Monday of the month you would delete previous data then perform a current back up to the media labelled for that Monday.
Strategy Three: This is an extension of Strategy Two. It adds a year of monthly backups.

Replace the 1st Monday media in Strategy Two with 12 media labelled January, February, ..., December. On the first Monday of each month use the media labelled for that month erasing the data from the previous backup to that media. All other days of the month are as in Strategy Two.
Strategy Four: This is the minimalist backup strategy and is a cut down version of Strategy One. Use two media rather than five and label them A and B. Back up your data files daily alternating between the two media. This protects you against hard disk failure but not against viruses. Destructive viruses often go undetected for relatively long periods of time and you may need a backup that goes back days or weeks to recover data damaged by a virus. You should never use only one disk or tape for backups. All media can fail so you should have at least two backups in addition to working copies of your data.

Strategy Five: This is the easiest strategy if it's available to you. If you are faculty or staff at a university and your computer is on a LAN (local area network), you may be able to keep your files on a LAN file server where files are backed up to tape every night. Check with your local computer support group to see if this is the case and what restrictions or costs might be in place.

Which strategy to use depends on how far back in time you want to be able to restore data from and how much effort you are willing to devote to backups. Strategy Three is no more work than Strategy One, but requires more media and slightly more organization. If you use backup software you may be able to use partial backups that are called incremental and differential backups. Both start by doing a full backup followed by:

Incremental backups: They copy only files that have changed since the last backup into a new backup set. This is the most space efficient backup type but is the most difficult to do restores from. You might be able to do a full backup plus four incremental backups on a single media. If so, you would only need one disk or tape per week but might need to look in five different backup sets to find the right one to restore a file from. A complete restore requires restoring all five backup sets. Using incremental backups this way would lose a week's worth of backups if the media goes bad.

Differential backups: They copy all files that have changed since the last full backup into a new backup set. This means you only need to look in the full backup set and the most recent differential backup set to find the most recent version of a file. You only need to restore the full backup set and the most recent differential backup set to know you have the most recent version of all your data. Like the incremental backups, you might be able to put a full week of backups onto a single disk or tape and risk losing a full week of backup files if the media goes bad.

Complete backups on a daily basis are easiest to restore from. You use your most recent backup to recover the most recent version of a data file or go back to the previous backup that is appropriate if you want an earlier version of the file.

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Free Spyware Protection: What Is It And Why Does It Exist?

By: Grigory Kononenko

Free spyware protection is something you should consider if you have computer problems that just don't go away. What is the best thing to? What is the best software to download? What is the answer?

Hackers, viruses and other nasty things are abundant these days. The only defense you have against it, are spyware removers. Even if you have the most expensive computer on the market, you can still easily become a victim of a hacker attack. Your computer can be cracked open before you blink your eye.

The least that can happen when you get spyware on your computer, is the performance issues and loss of data. In this case, you are lucky! There are a lot of other, more dangerous things that can potentially happen, such as identity theft.

Ever paid for something you haven't bought? Better check your credit card statements thoroughly! A very common occurrence is where a credit card number gets spied out of a computer and is used for days, weeks, and sometimes months before the owner finds out.

Here are just a few examples how spyware can destroy your computer. If you want to do something about it, you should consider some options, such as free spyware protection.

How do you choose a free spyware protection program?

The first thing you should do is find a suitable free spyware protection program. The best way to get them is online. A lot of sites are offering different versions of these programs.

Before you pick one, it's a good idea to compare some alternatives and pick one that you think is best. Think about features, the capabilities. Think about what you want to achieve. Do you just want something simple? Is something more advanced, with complex advanced removal options?

Why are free spyware protection programs available?

These programs are made available on the internet for free, because the makers of the programs want to let the users see the functionality of the programs.

These programs will clear some, most or even all of your spyware. But generally, they will also have premium features, such as real-time protection, which are only available to premium users. So for a small fee you can later upgrade the program should you wish.

It generally is recommended that you use more than one free spyware protection program at the same time, as there is no single program that can remove and protect you from all known spyware. Even though it may cost you more upfront, that investment will be well worth it once you realise how much spyware you really have on your computer.

The most important thing to remember is to download your free spyware protection programs from a trustable, reliable source. Be careful, because there are fake spyware protection programs out there, and they are sure to do harm than good. You may end up having more problems than what you started with.

Be sure to check sites like Free Spyware Buster on comparisons of various Free Spyware Protection programs. Sites like this will be able to point you in the right direction, and let you choose the correct free spyware protection program. Organize your data so it is easy to back up.

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Passive Income Secrets - 5 Elements You Need To Create A Repeatable AdSense Income!

AdSense is one proven way to generate a passive income online. By studying how successful AdSense marketers build their online income, you can literally almost 'copy' their business model and rake in huge profits.

Here are 5 elements you need to create a repeatable AdSense income:

1. Content

You absolutely must have content that readers will want to read. One way to get content easily is to grab reprint rights articles from an article directory or two and publish them on your blog or website.

2. A Blog

A blog sure is effective for search engine optimization purposes. Blog platforms such as Wordpress and Blogger are recognized by Google and you can easily get your blog to rank well for popularly searched terms.

3. Ad Banners That Stand Out

Although some AdSense 'gurus' advice you to make your ads blend in to the rest of your website, that just makes them disappear into the background even more! Contrary to this, you'd want to make your ads conspicuous so that they will be clicked upon more often.

4. Profitable Niches

You'd want to enter AdSense niches that are profitable so you get the maximum amounts for your clicks. One way to find out these profitable niche keywords is to go to Top Paying Keywords dot com.

5. Massive Traffic

The final and most crucial element of AdSense success is to have massive traffic coming to your blogs or websites. You'd want to use a variety of automated and 'hands-on' methods like search engine optimization and article marketing. Without traffic, nothing happens!

Fabian Tan is a well-known Internet Marketing expert and the author of the popular 51-page Report:

"Murder Your Job: How To Build Cash Sucking Autopilot Businesses In 30 Days Or Less!"

Head over to http://www.MurderYourJob.com to get your FREE copy now before it's gone!

Article Source: http://EzineArticles.com/?expert=Fabian_Tan

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